intrvw

r# 3 if the error is reduced by increasing or decreasing the duration then it is known as integral controller and if the error is redued with respect to the rate then it is known as derivative controller.

=TEMP RANGE OF PT100 IS -250 TO 850 DEGREE C=NAME ANY TWO PHOTO CONDUTIVE MATERIALS?-LEAD SULPHIDE,LEAD SELENIDE

=an analog input/output is jsut the variable signal which come and go to the field instruments linearly in the form of 4-20 ma.while the digital input/output is the signal which comes in the form of 0 or 1 that is for the motor/pumps start stop and their feedbacks.

=In case of 4 wire transmitter, 2 wire is used to give power and other 2 wire to transmit the signal. In case of 2 wire transmitter, the 2 wire carries the power as well as the signal. Example- 4to 20 mA is flowing through the 2 wire and according to level the current is changing.

=Process hook up means process connections or primary connections.Means sensing lines,fittings, elbow, nipples et

=SCADA stands for supervisory control and data acquisition.It generally refers to industrial control systems: computersystems that monitor and control industrial, infrastructure,or facility-based processes

A SCADA System usually consists of the following subsystems:hmi plcrtucommunication interfaceHMI is the apparatus which presents process data to a humanoperator, and through this, the human operator monitors andcontrols the process.so basically we can say hmi is a part of scada but scada isnot the subsystem of hmi

=Re: A pressure Tx accuracy is 0.2%. Signal o/p is 4-20ma.span is 16 Ma.how many deviate the o/p then

calibration needed Ans-2/100*16=.32ma

=Re: Why we used cage in control valve? Answer# 2

The walls of the cage contain openings that usuallydetermine the flow characteristic of the control valvein flashing, upstream pressure decreases to vana contractapoint.at this point,pressure is called as vena contractapressure.after this point , pressure recovery starts but itsnot that enough to take down stream pressure above thevapour pressure. means downstream press< vapour press.as aresult bubbles are formed and they remain there ,notcollapas.this is flashing,combination og liquid and vapourflow at downstram.in CAVITATION also, same situation arises.only difference is downstream pressure is > vapour pressure,therefore bubbles formed are burst.

=mps converts ac to fixed dc voltage

the desired vtg can be obtained by choosing ic's , resistors , capacitors of the desired value ( 5 - 20 voltage range )

=LCN: Local Control Network is the Network Were number of UCN(Universal Control Network)are Connected

UCN: Universal Control Network Were the Single DCS,PLC,FSC etc..are Connected These number of UCN's with DCS,PLC,FSC etc.are then Connected to LCN and through LCN to all Server.by waqas niazi to faran ashraf

=e: Name four general (not technical) criteria that would you consider important, when deciding upon a particular control valve? Answer# 1

the fluid medium to be used the fluid physical properties ( viscosity , density , temperature etc )

the frequency of application of valve i.e the no of times opened or closed in a hour

the flow rate , pressure desired c time , volume to be transferred in specific time for flowing media etc

the operation to control valve manual , automatic , pneumatic , hydraulic etc

=What is an instrumentation amplifier? How is it better than a differential amplifier when handling outputs from a wheatstone's bridge? Answer# 1

The instrumentation amplifier has high CMRR, high stability of gain with respect to temperature and high linearity of

gain. It also has very input resistance ensuring that source resistance unbalances will have negligible effect on performance. In addition, passive filters can easiy be incorporated at input to reduce common mode and differential mode noise. In a sinple differential amplifier, the gain linearity is poorer, the input resistance is much lesser (so errors due to source resistance unbalances can be high), CMRR depends on proper ratio matching of resistors and can deteriorate with temperature to temperature effects on resistors.

=Re: How does one detrmine the direction of movement of core in an LVDT? Answer# 2

By measuring the primary and secondary voltages and compare this with the null position.the movement can be identified easily

=Re: What is cold junction compensation in thermocouples? How is it achieved? Answer# 1

A thermocouple measurement involves two thermocouples, one at hot junction and another, a cold junction, at 0degC. Maintaining this cold junction at 0 degC is cumbersome, and it is easier if it can be at room temperature. The indicated temperature will be lesser by "room temperature value", and if room temperature varies, then the indicated temperature also varies. Measures to counteract these errors is called cold junction compensation. When cold junction temperature increases, the voltage from thermocouple decreases. If an equivalent voltage is added to this, then cold junction errors can be removed.One can monitor this cold junction (near the terminals where the thermocouples get connected to copper wires of indicator)

using another sensor, and add an equivalent voltage to thermocouple voltage to compensate for changes in cold junction. Alternatively, the ambient temperature measured can be added to temperature computed from thermocouple voltage to get CJC.

=: How can one improve linearity of an RTD based temperature measurement system?

=What is sensitivity of K type thermocouple? Is polarity important in thermocouple connections? Answer# 1

About 40uV/degC.Polarity is ver important in thermocouple connections. Otherwise, when temperature is increased, displayed value of temperature will decrease!

=e: WHAT PRINCIPLE OF GAS ANALYSER( CO,CO2,N2) Answer# 1

Zarkonia principle

=e: what is the difference between single and double compression cable gland Answer# 1

Normal Cable Gland is also called Single Compression Cable Gland. As the name suggests, while you tighten the gland, the grip or compression is effected only at one p[lace (i.e.) at the cable armour only. There is scope for moisture and corrosive vapour to enter the gland and thus into the cable.

Whereas in Double-Compression Glnad, the compression happens both at the cable armour as well as at the inner sheath. This is sort of two sealings. Hence, chances of moisture or vapour entry are minimised. Hence these glands are also known as Weather-proof cable glands or Flame-proof cable glands.

=how can you set a zero and span of transmitter?

=IS THEIR ANY AGEING EFFECT ON FLOW NOZZLE, ORIFICE, MANIFOLD, OR TRANSMITTER ?

= Re: what do you mean by smart instruments?explain with example Answer# 1

which uses microprocessor

= Re: How to Calibrate Transducers? Can you give me a step by ste procedure? Answer# 1

The transducers are calibrated against reference standardswhich are atleast 10 times more accurate then the transducerto be calibrated.

Let me elaborate by giving an example.

Orifice plate infers flow rate by measuring differentialpressure.so to calibrate orifice plate, reference standardsay magnetic flowmeter is used which measures flow rate.sayflow range is 0-100 lpm and at every 10 lpm, differentialpressure across orifice is measured and constant is evolvedbetween flow rate and differential pressure. This constantis also known as discharge coefficient or calibrationconstant and one dimensional bernolli's equation is used tocompute this constant.Now once you know the constant the orifice flow element isready to be used in any line size without using anyreference standard.What is linearity of RTD over 0 to 200 degC? Answer# 1

=0.4% of FS. The Pt 100 has 100 ohms at 0 degC, 175.8 ohms

at 200 degC. However at 100 degC, resistance is not 137.9 ohms but 138.5 ohms, which is 0.6 ohms higher. [Now 0.6/(175.8- 100)]*100% is 0.8%. However with respect to a best fit straight line, the deviation from straight line is +/- 0.4% of FS.

=define feed forward control loop with example and drawing? Honeywell 0 73 how to calibrate mass flow meter (Coriolis)? Example calibration range: 0 to 2500 kg/hr line size 3" fluid:

Etheline glycol (MEG) Honeywell 0 62

=What is Hysteresis mean in Instrument? Answer# 1

The delay between the action and reaction of a measuringinstrument.

=Why we use negetive (-)voltage in vibration system

= Re: what is cascade loop and how it work and why it used instead of PID single loop? In cascade, Which loop is faster and slower? Please explain with loop drawing and example... Answer# 1

in cascade loop

=a flow transmitter [range-0-400mbar] connected in process line. please explain me how to calibrate the flow transmitter , & how to do static error

= Re: modbus and profibus communication difference? Answer# 1

The philosophy for modbus and profibus is same.....thedifference is1.modbus you can go up to 1200m only in the case of profibusyou can go up to 2-5 km.2.In modbus the speed will be 125kbs where profibus it willbe 1.5 mbs to 12mbs.3.In modbus you can connect maximum 32 devices for RS485

where in Profibus you can go upto 127devies without repeate

=Re: Can anybody tell me application of PLC,DCS,SCADA. Answer# 1

PLC is programmable logic controller. It has got wide application like controlling a drive, motor or any other batch process. PLC's have got capacity to handle less number of input.DCS is distributed control system. It has got application where there are large number of inputs/outputs. Used for large process handling.SCADAA is supervisory control and data acqusition. SCADA System usually consists of the following subsystems:PLC, HMI,RTU.

=why generation of syncronized generator increases when frequency of grid is less then 50Hz & generation decreases when grid frequency goes up from 50 Hz, as comparision with set value entered in govering panel?

=How to get Cv of control valve having following parameter ,i.e inlet pressure 4.5kg/cm2 outlet pressure 1 kg/cm2 specific gravity 0.808

=How do bending tubing provide better measurement than using tubing fittings such as elbows? 0 44

How can corrosion alter the accuracy and precision of a C- Bourdon tube pressure gauge?

=Re: How does a strain gauge measure pressure?

=Question

why we set -10 volt in vibration sensor output,why not +10

=TEMPERATURE VARIATION FOR FREQUENTLY. TVS 0 38 ALL INSTRUMENTS WORKING PRINCIPLE

=Question

Condensation within a sight glass?Would you expect there to be more problems when using a sight glass if there is condensation on the inside or the outside of the glass, and why?

= Re: What is the difference between rich gas and lean gas? Answer# 1

Rich gas has c1.c2.c3Lean gas has only c1.c2

=Re: In separator VFD frequently trip with OVER VOLTAGE Fault What is the reason? Answer# 2

over load

=Re: please suggest me, how can i change the display setting in term of unit in place of % of Honeywell pressure transmitter ST3000S100? Answer# 1

connect hart communicator,go to displa settings and then change the unit.

=Is wet leg type system nessesary to measure water level of steam DRUM? How the transmitter is calibrated to measure this level?

=how to solve temperature error in compressor? 1 198 Is wet leg type system nessesary to measure water level of steam DRUM? How the transmitter is calibrated to measure this level? 0 53

what is the approximate cost of U tube manometer having range 1000mmwc to 1000mmwc? 1

77 How is PH sensor works ? 0 46 How will you calibrate PID controller? explain

with example. 0 87 for commissioning the DPT and Flow Transmitter , what kind of necessary

activities we have to check and do? specially that orifice flange valve[ isolation valve} L&T 0 75

Please tell me details about Sox,Nox,SWAS analyser????

=in any transimitter (flow/level) there are three terminals for supply& test (+,-,+)in two wire,24VDC given to Tx.,but how 4-20 ma signal travels thru same wire (as it is for 24VDC input supply)?

= Re: Can a Differential Pressure Transmitter be used as a normal pressure transmitter?? Answer# 1

yes..you can use DPT as PT by keeping LP line open to atmosphere.connect the supply in HP line.

=where proximity sensor installed on tank in loading arm application

=Re: which gas or which liquid is filled in capillary of dial type temperature indicators on power transformers

=Re: relation between level and differential pressure. Answer# 1

can measure level by using Differential Pressure. It infersliquid level by measuring the pressure generated by the liquid.

Pressure = Specific gravity x Height of the liquid column.

=An engineering term STALL used in compressor operation what it means? 1 217 could

someone explain for me what is 32-bit Floating Point ? Thanks 0 41 I have a steam flow DP transmitter that has output swinging. Steam valve is in manual.I have good steam pressure. The impulse lines have steam tracing on them. The steam tracing has a hole in it that is blowing raw steam on the high side impulse line only. Could this be causing the swinging?

=how to calibrate corollaries (Mass flow meter)? Honeywell 0 62 can we create an interrupt in plc through scada?

=Re: what type of cables are used for f&G systems and detectors, what is the standard colour? Answer# 1

standard colour used for FGS is orange.

= Re: What is governor of turbine? Answer# 1

Governer is used to increase or decrease fuel supply so asto maintain a constant speed in a generator or turbine.Any change in speed will affect the frequency which is verycritical in power generators.In a vehicle, you will manually control the fuel supplyusing accelerator pedal but it can not be done in powergenerators as you have to maintain constant speedirrespective of load.

=Re: how to control motor load with rpm or vfd Answer# 1

The Motor speed can be controlled through a closed loop system (i.e. PID loop) with either process value of its speed.

=

Re: why the derivative in PID is always set to zero? Answer# 1

Derivative gain is used to take the preventive action in control. i.e. it gives the corrective action for future based on the nature of present error. And Derivative action is used to fast the porcess. Due to this property of Derivative gain, the process may become fast and unstable. To avoid this, generally Derivative gain is kept as minimum as possible i.e. zero

=what is reason behind boiler drum level transmitter range put -450 to 0 mmh2o.

= Re: how to calibrate absolute pressure transmitter Answer# 1

You connect it to a vacuum pump with a calibrated absolutepressure gauge (electronic or mechanical). compare the tworeadings. adjust as needed. Normal output is 4-20. 4 being aperfect vacuum . 20 ma being the upper end of your range

= Re: What means zero and span in transmitter callibration.

=Re: Why even multiple power supplu r used in instrumentation system? Answer# 1

Redundancy concepts.For server we have two power supplies.one is master and other standy.Same for Automation processors,OSM also.For I/O cabinets also

the main thing the system should not get disturbed itself and the process

== Re: Can all intrinsic safe transmitters are provided with inbuilt zener barriers? why Answer# 1

YES ALL INTYRENSIC SAFE TRANSMITTERS R BOUNDED WITH ZENSER BARRIERS BECAUSE THESE R HAZARDOUS SIGNALS COMMING FROM THE FIELD, SO TO AVOID ANY DANGEROUS EFFECT TOWARDS THE PANNEL SIDE BARRIERS R USED THESE R SO THAT IF MORE CURRENT IS COMMING FROM YHE FIELD THEN THE BARRIER BECOMES OPENE TO B SAFE FOR PANEL SIDE.

=Re: what is the characteristics of control valve?

==Re: what is the path to communicate from profi to ofc.what is the means of communication.what is multi cire cable in ofc. Answer# 1

1. Communication is the data sharing technic between any two or more nodes/devices .2. Profi bus is one type of communciation protocol it sends data from one node to another.It can integrates with Optic fiber cable(OFC) by Protocol converter such as gateways.3.OFC has two types of communiction techniques 1.Single mode - Upto 2Km above 2.Multi mode - Upto 500m-2Km

==Re: how to calibrate the interface leveltrol Answer# 1

interface LT use in that application where two liquid mixedin a tank. For calibration interface type LT theseinstructions to be follows -

1. set upper & lower range.2. set upper & lower density.3. after then put weight according calibration data sheet & note readings at every sample weights. 4. If the output have some error then give lower trim & upper trim command to LT with weight at 0% & 100%.5. recheck all value at different weights.

this LT work upon bouncy principal. which liquid will havehigh density that will be make reference to LT.

==Re: what do u mean by 2/3 soleniod valves?

==how many types of spped sensors n vibration sensors?their basic principle n connection?

==Re: can a control valve works without positioner?why need tunning of c/v? Answer# 2

first of all we cant say any valve as a control valve without positioner... because we know that control valve is afinal control element.. we only say any valve as a controlvalve when its acted as percentage operation as per processrequirement. with out positioner this is acted as a simpleon off valve... because percentage opening not possible without positioner... & we need to calibration the positionerbecause cv alwys maintain the process in aspect of its final

contron ability.... i.e if process need to open the cv 25%if the positioner not calibrated then it may be open 30 or10 % for example... thats why we need to calibrate thepositioner.....

==Noramaly room temp. is msrd by thermometers. yes,from RTD we can also measures room temp. if all other perameters are neglected but not by thermocouple because of two juctions. Diff:- 1)rtd is low range temp.sensorbut thermocouple is for high range temp.2)rtd measures temp.with change in resistance, thermocouple measures temp.with reference of cold junction, its output in mV.3)rtd have large bulb size than thermocouple.4)rtd have single metal while themocouple have two dissimiler metal wires....etc.

==Question

what do u mean by compensation n pid tunning?in pid tunning what you tunned?is it possible 2 tune p i d

==Re: What is Fieldbus?

==Question

what is working principle of presure and temperature guage

== Re: in i/o panel for digital ouput(do) how much power(in volts) we must give? Answer# 1

first thing we have to pick up the internal relay in i/o panel for that we can use 24v dc,ac.it is a potential free contact what ever the supply we r giving to he relay we

will get the same after the do is generate

==Question

Functions of electropneumatic valve positioner:

= Re: Reasons for using current as signal Answer# 1

1.No signal loss in current transmission.2.AS per ANSI std. (4 to 20mA) signal used which is intrinsically safe signal in hazardous area.3.inherent insensitivity to electrical noise.4.All the components in the loop drop voltage due to the signaling current flowing through them. The signaling current is not affected by these voltage drops as long as the power supply voltage is greater than the sum of the voltage drops around the loop at maximum signaling current of 20mA.

=wht is snap action switch?where it is used?is there any diff between snap action switch and normal pressure switch?

==how to overhaul control valves.what are the proper procedures. QAFCO 1 256 How to

find out turn down ratio of Pressure transmitter? 0 168 What is the working principle of

Bentley Nevada 3300 0 78 Can anyone send most commonly asked interview question in Oil

& Gas industry 0 31 Hello friends i need check lists of different instruments during the Erection and commissioning in thermal power plant.Please help me.My Mail id is

[email protected]/[email protected] Thanks Nabakishore Biswal 0 36 What is

an SCR? GAIL 3 462 What are the different types of temperature sensors and the principle they work on?

==Re: how to overhaul control valves.what are the proper procedures. Answer# 1

It is a very lengthy topic. I will try to explain some major point.

1. Mark the parts orientation before dismantling, such as mark at body, bonnet, yoke, pressure chambers casing.2. Note down the threads upper side and lower side of coupling.3. Suppose, valve is air to open, open it with direct feeding signal to diaphragm upto 5%.4. remove the coupling.5. release load pressure6. Loose yoke nut and remove yoke from bonnet7. Remove gland packing nuts,remove gland pusher8. Dismantle bonnet nuts9. Remove bonnet from body10. Remove trim material

=What is DCS? GAIL 2 550 What do you know about gail? GAIL 0 32 How will

you measure surface temperature of SUN? GAIL 2 79 What does a fire detector detects? GAIL

1 307 Introduce yourself which is not present in your biodata? GAIL 0 40 WHAT IS TSI? HOW ITS WORK

==Re: How will you measure surface temperature of SUN? Answer# 2

by using optical pyrometer

==Re: how does we do bench calibration of a differential transmitter. Answer# 1

dp trasmitter is having range of few w/c. take example of you want to calibrate 0-50 in h2o dp transmitter. connect power supply and multimeter to connection point. connect small hand pump to high side of dp transmitter. keep low side of dp open to atmosphere. first check 4ma when both connection are open to atmosphere. then connect hand pump to high side and give 12.5, 25.0,37.5 & 50 in h20 and check 8,12,16,&20 ma o/p.

==Re: what is difference between two wire &three wire pt 100 ? Answer# 1

two wire RTD use for short distance,three wire RTD use for long distance because of resistance compensation.

==e: what is the basic principal of vertax flow meter Answer# 1

vortex is natural phenomena occurring when liquid flowaround a bluff object.For e.g when we throw the stone in water it generates vortexin round circle.same happens when a object is placed in between running liquid.In vortex flow meter same is used and the frequency ofvortex generated is directly proportional to velocity ofliquid flowin.

==what is the zero elevation and zero supresstion in level measurement, how can use it?

== Re: why we use by pas on a positioner? When can a by pass be not used on a positioner ?

== Re: What is a flow meter? Answer# 1

A flowmeter is an instrument used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas.

==Q- voltage source of 12v is driving the circuit.if circut draw the current of 0.5A them source voltage

will became 11.8v.what is the power dilevered by source when circuit draw 5A current ? Ecil 0 68

Q- Control problem are mainly classified in _____ types. a-)4 b-)3 c-)6 d-)nono of these Few of them i know is 1- regulator type problem (eg- Air conditioner) 2- tracking problem (eg missile trcking problem) 3- sybernatics 4- optimal control problem

==Question

what is span adjusment of transmitter?what is the function of positioner/

== Re: what is the difference b/w magnetic flow meter&mass flow meter? which one is best? Answer# 1

Electromagnetic flowmeters:Used to measure all electrically conductive liquids (> 5 µS/cm) with or without solids, e.g. water, wastewater, sludge, slurries, pastes, acids, alkalis, juices, fruit pulp, etc.

Used in water/wastewater, chemicals, pharmaceuticals, pulp and paper, foodstuffs, etc. Electromagnetic flowmeters are even robust enough to be used in mining.

Mass flow meters:

Virtually all fluids can be measured: cleaning agents and solvents, fuels, vegetable oils, animal fats, latex, silicon oils, alcohol, fruit solutions, toothpaste, vinegar, ketchup, mayonnaise, gases, liquefied gases, etc.

Mass flow, density and temperature (the primary measured variables) can be used to derive other variables such as volume flow, solid contents, concentrations, and complex density functions. i.e. One for all - multivariable metering.

==What is meant by Fail Safe Condition in PLC? 3 795 What is the difference between dry

contact and wet contact? 2 650 Why Current(Ampere) is chosen as Fundamental Quanties not Charge(coulomb)

==Q- Ordinary Water Tap is which kind of controller ? P , PI or PID i chose the option of ON - OFF type

controller but ambiguity is that for different positioning of tap we get different flow 0 86 Q- What are the application in which PNP transistor is preferred over NPN ?

==Re: Q- Which of the following is Close loop system - a-)respiratory System b-)traffic light system c-)washing machine d-)Room heater my option is A, what is our take on option B & C Answer# 2

D - room heater

=In VVVF DRIVES VOLTAGE IS ALSO VARY WITH THE FREQUENCY. HOW? WHAT IS THE DIRECT FORMULA RELATING THESE TWO

=Re: Q- Why Phase tester is only used for checking AC not DC ? Answer# 1

A mains tester works because the potential difference between the live and Earth makes a very small (imperceptible) current flow through the tester and our body to Earth. This current is just enough to light the lamp / Neon. When you stick it in the Neutral socket, the potential difference (just a volt or two, usually) is not enough to give sufficient current to light the neon.When the tester light glows, it mean electrons flow like,from live terminal > tester > body > floor & walls of building > inside the earth>goes back to the generator, via earth or neutral conductor (Please note that somewhere, Neutral and Earth are connected together so we have, in effect, a huge loop of circuit.)

Above description is for AC supply only ( path complete thorough earth or nutral to generator neutral), however please note the fhilosophy is not applicable for DC supply where - V is in floting condition (not grounded or earthed) so due to un completation of that circuit tester light will not glow.

==whats the problem will arrise if we rotate the hosing screw of the differential pressure transmitter? 0

59 in valve is constructed as per SME B 16.34, then which standard is used for fire testing of

valve?. 0 42 in control valve is constructed as per API 6D or API 6A, then which standard is

used for fire testing of valve?. 0 50 what are the different types of communication cables used in automation and what are the difference in the cables

==Re: how to rectify the problem ,if we erected the DPT instrument wrongly of hp on lp side and lp on hp side? Answer# 1

1)Remove and re install correctly2)Change calibration range if presently set as 0 to 1000 mmH2O to 1000 to 0 mmH20 and make required changes in control system to see it correct.

==Re: what the differant between Wet Leg /Dry Leg Answer# 1

They are diffrential pressure transmitter "installationtechnique" used in "level measurement"

When installing diffrential pressure transmitter we attach 2impulse lines with high & low transmitter sides, the 1attached to low side is empty impulse line so it is "dryleg" or it's filled with a sealing liquid with densitygreater than the process liquid so it is "wet leg".

We use "dry leg" for closed pressurized tank.

We use "wet leg" for closed pressurized tank also but if wehave the probability of process liquid condensable vaporwhich will give a faulty measurement.

If we have an open tank, the Tx low side is atmospheri

==Re: wt kind of business we can do by usig PLC? Answer# 1

Normmally PLC is Programmable logic controller used to automate the process / machines to reduce manual interactions and to increase the productivity and quality.

==Re: why we use casced loop Answer# 1

We use CASECAD loop to inhance the capability of the process.normally we use this loop at BFW(boiler feed water) tanks and at the BMS(burner managment system)to inhance the burning ratio of fuel that become more relaiable for our firing.because we are using here two controller(two setpoints)these both controller makes process much more flexible and accurate.

==Re: DC motor and DC Drives working funda?

==Re: what is the way of measuring air flow in air duct?explaim instruments used and DP creation in line?

====What is instrumentation engineering? 

What are the duties of an instrumentation engineer? 

How to make a calibration for differential pressure? 

What does an instrumentation engineer do? 

What is instrumentation engineering? 

What is virtual instrumentation? 

What is the operation philosophy of proximity velocity sensor? 

What is DDC-MIS? 

What is see back effect? 

What is the difference between PLC & DCS? 

What is the difference between SCADA and DCS? 

What is pressure transmitter? 

What is the working principle of vortex flow meter? 

What is solenoid valve? 

What is fault tolerant system? 

How to calibrate ph meter? 

Which instrument is used to calibrate the pressure switch? 

What is the maximum operative of Drive? 

What is instrumentation amplifier? 

What is cascade controller? 

What are the levels of automation? 

What is instrumentation? 

What is meant by speed control in turbine? 

What is electronics? 

What is the difference between venture and orifice meters? 

What is up sampling and down sampling? 

Explain about the synchronization panel? 

What is meaning of software redundancy and hardware redundancy? 

What is difference between OP AMP and differential amplifier? 

What is the electronic transmitter frequency? 

What is the difference between digital signal processing and discrete signal processing? 

What is the advantage by using PID controller than P& PID? 

What is the difference between DELTA-V & FOUNDATION FIELD BUS? 

What is the difference between servo valve & proportional valve? 

What is the difference between instruments and instrumentation? 

What is BMS (Building Management System)? 

What is mean by loop checking? 

Which standard is used for calibration of Control Valves? 

What is an ambient temperature? 

===The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air

==what is the safety integrity levels (SIL) Answer# 1

Safety Integrity Level (SIL) is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a Safety Instrumented Function (SIF)

==WHY IT IS USED ON ESD ON OFF VALVES? Answer# 2

Esd valves are required by gov. safety standards to be checked periodically to be able to stroke i.e. (move to a determined position, usually 90 % and back to original position.) If the valve does as required, it passes function test and can remain in service. In some applications valves tend to stay in one position for long periods of time. This often has an effect on the bearings "freezing" up, and in an emergency situation the valve may not close when required.

==he Pirani gauge is a robust thermal conductivity gauge used for the measurement of the pressures in vacuum systems.

==een accelerometer vibration sensor and proximity vibration sensor Answer# 2

Accelerometers are a piezo-electronic (crystal) device. A pre- loaded crystal is charged with current and as the crystal is compressed or de-compressed by vibration an output proportional to g's (gravity) is provided. A "g" is equal to 9.80 meters/second2 or one (1) standard earth gravity. Accelerometers are normally used for high-frequency bearing cap vibration readings (Case/Bearing Cap Absolute on machines using rolling element bearings. Usually the output is integrated electronically to velocity (in/sec or mm/sec). Other applications include monitoring Gears and High Frequency Applications.

Eddy or Proximity Probes are a displacement device that measure the relative motion between the probe mounting location and the target (shaft). Output is directly proportional to displacement and is usually measured in mils (.001") or millimeters (mm).Eddy Probes are used on machines with Journal (Sleeve) type bearings. Where the measurement of motion between the Bearing and Shaft is critical.

==: radial & axial vibration sensor output voltage is ac or dc volt? Answer# 1

dc

=Would you expect an ultrasonic level device to work better in a pressure vessel with a high pressure or a strong vacuum, and why?

Answer-f you are trying to measure the level of a liquid in a vessel, think what happens to that liquid if subjected to a strong vacuum - it will tend to boil.Now consider, which is easier to measure the level of - a liquid with a calm surface, or one where the surface is boiling

=how can we tune a PID. If it is by zeiger nichols method..please explain briefly with help of an example. =Consider a level troll. i am getting a correct value in 4mA and 20mA. the value in the middle(30 to 60%)is disturbed and i am not getting the appropriate value. what is the solution to normalize the level and to get the correct value.. Answer# 2

a) calc the hyteresis and reset the 4-20 to it, accepting the deviation in the middle

b) test the amount of deviation @ 4ma,8ma,12ma, 16ma,&20ma and see if slope is repeatable, write program correction for slope

c) Your instrument has a hardware issue, do the right thing

and replace it.

=why we use negative 24vdc to a proximeter Answer

In -ve voltage the rate of distabance is lesser than +ve voltege.So we using -10vdc(some time-9.7 to -9.8vdc is acceptable )

==You need one water manometer,one T fitting and one flexiblerubber hose. Connect the hose,the manometer and the pressuregauge to the T fitting without any leakage. Blow air (by mouth)through hose till span (cross check atwater manometer) and fold the rubber hose. Adjust span setting.Then drop the pressure by unfolding the hose and adjust forzero.Repeat process two or three times.Now check for mid-range, if it is ok, then calibration is over

==what is the use of glycol filling in seal pot (or) condensate pot in instrument impluse line? Answer# 1

it serve as protection to the instrument.it contain glycerinor water vapor.with the principles of pascals law.externalpressure will be undiminished

==what is pressure control IBM    0   55 what is plc communication?

=What is cable size for intrenal wiring in DCS or PLC ,from any card to Terminal amd Why==How is a capacitor bank is designed ?==-what is the analog input , analog output , digital output, digital input geven to the MSSV , CBD, IBD , START UP VENT , BOILER FEED PUMP , AOP, CEP , ETC

==When cryogenic control valve will be applied? Answer

At Lowest temperature area applications.(Below 0 Deg Cent

==please tel me the calibration of pneumatic controler.

==suggest a sensor to measure rapidly varying temperature? Answer

What is your temperature range? if it is 0 to 500 deg. C and no vibration in area then you can easly go for RTD with transmitter and indicator.How high temp. you can use J type thermocouple with transmitter and indicator.above 1000 dg c use K type for R type. While using Thermocouple be carefull about Cold Junction Compensation

==why can't we use 5-20mA standard or some other instead of 4- 20mA? Answer# 2

4 - 20 ma is used because one resion is that control system like DCS AND PLC will accept (1 - 5vdc)only for that resion by connection 250 ohm resistand accross with ( 4 - 20 ma) we can get ( 1 to 5 vdc) (1vdc=4ma and 5vdc=20ma) this is as per ohms law ,V=IRIF V=4ma*250ohm=1vdc 20ma*250ohm=5vdc(4 - 20)ma is linear with(0 -100%) and the output will get linear from 4ma,

==what is mean by hot loop and cold loop testing, whts different between both Answer# 1

Cold Loop checking: Checking of wires continuity of respective field instrument-Junction box-DCS/PLC marshalling panel terminal.

Hot loop checking: Once you powerup your field instrument through DCS/PLC system, by stimulating process input from respective field instrument and cross check its responce at DCS/PLC sytsem

==Why some transmitter shows flow in MMWC and some in TPH?

==ORIFICE- USED IN WATER FLOW MEASUREMENTS.FLOW NOZZLE-USED IN STEAM & GAS FLOW MEASUREMENTS AT HIGH PRESSURE.AIR FOILS-USED IN DRAUGHTS FANS FOR AIR FLOW MEASUREMENTS.VENTURY-USED IN STEAM & GAS FLOW MEASUREMENTS AT LOW PRESSURE. ==

Re: what is isolation Transformer???...

Answer# 2

An isolation transformer is used to isolate the primary andsecondary circuits.To protect the source equipment from anyvoltage or earth fault in the load circuit.this transformermostly used in induction loads

==

e: 3element

Answer# 2

3 Element means,in that application is mostly used at Boiler feed water control for maintaing the drum level in steam drum,it consists 3 mesure devices,one is feed flow trx,second is steam flow trx,and third one is drum level(compensated)trx

==To measure the ground level tank (sump level), the RADAR level transmitter is the best.

The ULTRASONIC level transmitters also can be used.

At low cost the PURGE TYPE LEVEL MEASUREMENT can be done for the liquid/slurry level measure

==

what is the full form of psig.

Answer# 2 pound per square inch

==

: What is negative range in transmeter?

Answer# 1

Negative range of a transmitter is nothing but the range required to measure the vacuum of any equipment.If the pressure inside a tank or equipment drops below zero and goes to negative side then it is measured by the transmitter.Maximum of 14.7 psi vacuum can be measured at ideal conditions.For example a transmitter range is calibrated as -600 to +600 mm of water means the transmitter will measure negative pressure inside a pipe or column or tank and give output as 4 mA and at pressure of 600mm(positive )it give 20 mA output

==

Re: how to use one 4-20mA signal for two indicater or controller & give necessary precaution.

Answer# 2

Use Isolatrer/Mux 1 I/P & 2 output....... 1 230 v source to energise the mux and 2 outputs can be got...

==

diff between dead wt calibrator n pressue comparator?

Answer# 1

ok, deadweight calibrator is an intrument with hydraulic

pressure having lifting piston with plat round platform use to carry plate with round plat massess with standard value use as a standard reference to clibrate pressure gauge or any other pressurize instrsument. while the pressure comparator is having standard calibrated pressure/vacuum gauge use as a reference to check pressure/vacuum gauge. pneumatic transmitter, etc.not

==

what is written on orifice plate?

Answer# 2

mainly direction of flow and Size of bore in mm

==

Re: whey we conect ammeter in series and voltmeter in parallel in circuit

Answer# 1

Generally ammeter has internal resistance lower than the load resistance so if we connect the ammeter in series with load so maximum current flows through the ammeter so we can get current value. on the other hand voltmeter's internal resistance is very much higher than load resistance, so if we connect voltmeter in parallel with load then a minimum but constant current can flow through the voltmeter by calculating the voltage we can calculate the actual drop.

==

Re: what are the problem's will accure in dcs or plc hadware and what are the solution for it?

Answer# 1

The Main problem occurs in DCS/PLC hardware are

1) Channel failure2) I/O cord failur

==: Is there is a device to convert mechanical energy to electrical energy

==In PID, offset is thr due to proportional gain. In proportional gain, process value never achieve set point. It is more or less than set point bt near about set point. This difference is called offset. Integral is used to remove this offset

==

Re: how can be connected thermocouple in series?what is the need?

Answer# 1

thermocouple can connected in series with polarities reversed to measure difference between two temperatures.steps:1.take 2 themocouples2.connect in series and give it to mesuring device.3.display shows the temperature difference between two thermocouples.

==

Re: what is diff b/w neutron and ground?

Answer# 1

neutral ia used to complete a

circuit through itss return path,while earth is used for its prevantation of leakage /surge current.

==

What are the two program execution modes of PLC?

Answer# 1

i) Cyclic Execution ii) Event driven Execution

==

Re: what is the difference between mmhg & mmwc?. i want to calibrate a transmitter in the range of -100 to 300 mmwc. Which is the reference for calibrate the Tx,if mmwc not available?. Is it mmhg or mmho2?.

Answer# 1

Hi there,

mmwc (millimeters Water Column or Water Gauge)mmH2O milimeters water)

Let me explain the pressure value of each since I can seeyou have asked the same question earlier as well.

We all know that the gravitational acceleration of the earthis 9.80665 m/s2 as a accepted standard around the world.Our pressure system was also derived from this Universal Lawof Gravitation first developed by Sir Isaac Newton.I think we all heard the story about Newton sitting under anapple tree, an apple fell on his head, and he suddenlythought of the Universal Law of

5 Sam

Gravitation.Anyway long story short, memorize the following formula andyou will not ever get confused again about pressures and levels.1 meter height of any volume of clean water (1mWC) is equalto 9,81Kpa. That is the true and accurate pressure value of1meter height of water, regardless if it is in a smalltubing or the swimming pool or the ocean or the measuredheight in the vessel you want to do a level calibration on.a 1 meter height of clean water is always 9,81 Kpa.Ok I know still a bit confusing.

Due to the above information we can therefore say 1000mm ofWater Column is = to 1000mm Water = 9,81Kpa or1000mmWC = 1000mmH2O = 9,81Kpa

Now we all know the formula to calculate the calibrated zeroand span of our transmitters,sg x g x h = Kpa

So for a vessel with a zero to span distance of 1000mm and aproduct sg value of 1(clean water) we can do the calculation.1 x 9,81 x 1 = 9,81Kpaor if you want to work only in mmH2O,sg x h = mmH2O

1 x 1000 = 1000mmH2OSo now you can calibrate your transmitter for the aboveexample for LRV = 0Kpa and URV = 9,81Kpa or if you set theUOM on the transmitter to mmH20, you can calibrate it forLRV = 0mmH2O and URV = 1000mmH20.If the height or the sg value in your application differsjust substitute your values in the formulas and you will beable to do any level calibration on any PIPED DP transmitter.Remember these formulas are only for piped DP transmittersand not for capillary or wet leg applications.

Ok let's move on to:mmhg (millimeters mercury)

This UOM is normally used the measure vacuum and 1atmosphere = 760mmHg.You can also say 0mmHg = -101,3Kpa(a) since 1 atmosphere =101,3Kpa. The (a) indicates that we are talking aboutabsolute pressure and not gauge pressure.

If you really want to confuse yourself you can try andrelate what I have said above in the mmH2O example, to mmHg.You can say that 1000mmH2O = 73,56mmHg.Forget about mmHg and don't use

it, not even when you workon vacuum applications. Stick to Kpa or PSI or the UOM thatmakes sense to you and what you are use to. All the UOM arevery easy to convert to so always first convert themeasurement to units you are familiar with then start yourcalculations.Personally I only work in Kpa and mmH2O and I don't getconfused at all anymore.

So finally if you want to do you calibration as per yourquestion and you are SURE that the calibration is right, setyou UOM on your transmitter to mmH2O and set the LRV to-100mmH2O and the URV to 300mmH2O and put it back on line.

If you do not use a SMART transmitter convert yourcalibration values to Kpa or PSI and pump your transmitterup to these values and set the zero and span accordingly.-100mmwc to 300mmwc is the same as 0 to 400mmwc so if yourtransmitter cannot measure in the negative you can set thecalibration for 0 to 400mmwc as well, just make sure thezero is good at atmospheric presure.

Is This Answer Correct ? 11 Yes 0 No

==

i want to calibrate a transmitter in the range of -100 to 300 mmwc. How it is possible to measure -100 to 300?.

Hindalco 0 66

Explain any simple temperature control system. L&T 3 1032

Draw bode plot of any transfer function. Why is plotting bode necessary?

L&T 0 71

Explain Three way boiler. L&T 2 687

Tell about your IFFCO plant visit. L&T 0 82

Explain PID controller tuning & any one method used for it.

L&T 1 651

Which topics are covered in Process Control? L&T 0 57

Which is your favourite subject & explain any one topic of it.

L&T 0 87

what is the difference between E/P positioner and I/P positioner in control valve , in which application the respective positioner are used in.

0 104

what will be the output of the temparature transmitter if temp is 120 degre celcius.

Base-Automation

0 47

what is virtual instrumentation 0 125

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why relays are used with plc? 2 709

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0 74

If a differential pressure transmitter is calibrated for 0~2500 mmH2o and transmits a 4~20mA dc signal. The transmitter is placed across an orifice plate which is sized to create 2500 mmH2o differential at 5000m3/Hr a) what

is the flow rate when the transmitter signal is 13.0mA DC? b) what is the signal output of the transmitter when flow rate is 2500 m3/Hr ?

==

Re: Explain any simple temperature control system.

Answer# 2

at first u know what is temperature and what is controller

here, to see simple controller automatic iron box

one heater element and thermostat are used. when thetemperature raises thermostat controls the supply of theheater. it is called on off controller

==

What is the basic difference between Modbus and CAN Open Protocols

0 232

What is the reason for not giving very High Proportional Gain Kp in PID Controller?

ABB 2 1158

what is 24vdc live and dry supply 0 105

WHY WE WILL USE 0-24VdC IN ELECTRONIC CIRCUITS AND INSTRUMENTATION TRANSMITTERS?

Jindal 1 1445

Hi friends, from Aug 4th onwards iam getting spikes for analog inputs in our DCS for a period of 800ms. I throughly checked every thing, finally i found that the DI, DO's from MCC panels shields are terminated in the Signal Earth where Analog Input signals shields are terminated. Is there any problem with this type of termination?. i checked the induction voltage from MCC and getting around 25VAC, please suggest me in this concern. Our plant is 8months old only. DCS is Siemens Make Simatic PCS7, and the transmitters are Yokogawa make.

1 323

Whether the DI, DOs shields can be connected with Analog Input Shield Earthpit?

0 57

procedure to commission a drum level transmitter 1 512

pls any1 sugges me book for plc,dcs & scada.. 0 50

what is the differnce betweeen hart and smart tx 3 719

Can combine control system for Emergency control system (ESD)and Fire & Gas System ( F & G) is possble to built and offer to client? Can such system is as per Norms in India?

0 92

what is radar type level transmitters and its basic principle and how to calibrate it

ABB 2 1158

define COMPENSATION?? Bosch 3 884

define SIMULATION a and what is the need of it Siemens 3 870

Why all the drains(Gland sealing,ESV,Casing inlet etc) are directly connected to the flash tank instead of hotwell of the condensor in the power plant? My Email Id:[email protected]

Jindal 0 88

I want measure the volumetric flow of gas in waste heat recovery Boiler?Tell me how and which type of instruments required. Plz mail me:[email protected] Sam please post the answer .

0 63

E-Mail New Answers Answer Selected Questions Post New Instrumentation Question

==

Re: what is radar type level transmitters and its basic principle and how to calibrate it

Answer# 2

radar type level transmitter works on the principle of "time of flight system " actually this type of transmitter having antenna used to send and recive the

micro waves these waves having the frequency range in GHZ.by calculating the time required to send and recieve the data the distance can be calculated from the following expression velocity=2 distance/timetherefore distance =velocity *time /2 for zero level 4ma and for span 20ma has to set

==

efine SIMULATION a and what is the need of it

Answer# 3

simulation is tools for giving false appereance at input

for checking logic result

by simulation we can check stroke (operation) of control valves,control test of motor(start/stop),

and major advantage is ,during plant running,if any input not working properly,then by simulating we can rectify its problem in such way we can avoid the false tripping of plant

==

Re: define SIMULATION a and what is the need of it

Answer# 1

simulation means (The act of giving a false appearance of input or signal)to our system so that we can check our loop, response of relative

outputs, to bypass the protection, For example1.to check smoke, heat detectors response we apply magnet to activate its relay to energize a false fire signal to system.2.to check our loop during commissioning we apply mAs and get values in CCR.3.whenever such situation has to face that an erratic signal persisting protection and machine cannot start so we can apply necessary pulse to our logic and start our machine.

==

Re: how to know power plant process with corresbonding laws&thoeries

Answer# 1

Brayton cycle - Gas turbineRankine cycle - steam turbineMulti stage flushing - desalinationOHMs law - temp measurement,etcthomson effect,peltier effect - temp measurement

==

for indiacation of turbine(china) bearing temperature what type of sensor will be used(i.e. rtd or thermocouple or themister ) ? why it is ? i need clear explanation ?

2 427

how to know power plant process with corresbonding laws&thoeries

Bhel 1 443

how to calibrate control valves & power cylinders & ultra sonic level transmitters

ABB 0 90

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what is meant by turn down ratio? 1 975

what is meant by Valve reversibility? 2 528

Why hunting will occour in control valve? 4 1141

what is the difference between auto tuning and manual tuning of controllers(eg:PID,PI,PD CONTROLLERS )

GATE 2 876

What is the Differance between Graphics And SCADA Graphics? SCADA Graphics have less access?

Honeywell 3 941

why we used for range in pnumatic 3-15 psi and current 4-20 ma?

Jindal 5 1678

IS there any effect of vortex in low pressure side of the transmiter after the orific in feed water line? if yes then what is the calculation?

0 71

How to gennerate earth leakage monitoring alarm for solenoid valves in control system?

1 438

why used three wire in RTD. BARC 6 1957

what is the deferance between LCN and UCN. 1 597

In most process, speed of motor controlled by control system with a reference pot . Now if i start & it becomes uncontrollable, i.e.gets directly start & stop after certain time.Then which reasons can make such problem? can motor may be faulty?how?

==

Re: why we used for range in pnumatic 3-15 psi and current 4-20 ma?

Answer# 3

Hi,

4-20 mA standard is mainly to differentiate the conditionslive zero and dead zero i.e let me tell an example considera level sensor fixed in a tank . now the tank is empty .

0 Saravanamurthy

then the sensor will send the reading as 0mA this zero islive zero, if there is no standard as 4-20mA. in the samecase if there is any problem in the sensor output then alsothe reading ll be 0mA this zero is Dead zero.In order todifferentiate the fault and the original process conditionwe have chose this range as the standard.

Thanks & Regards,

S.I.Saravanamurthy.

Your comments are welcome

Is This Answer Correct ? 21 Yes 1 No

Re: why we used for range in pnumatic 3-15 psi and current 4-20 ma?

Answer# 4

For 4-20mA, the linearity scale comes proper, as well as if we want to convert, 4-20 mA than its easy to factorize, in range of, 0-25%,25-50%,50-75% and 75-100%.. So, If suppose, any control valve is needed to control, then it will be easier to control it... And for other reasons, as Mr.S.I.Saravanamurthy

Perfectly said, is the ZERo zone. so that, the Dead condition of any instrument can be differentiated from normal Zero parameter condition.

Thank you..Your comments are welcome

Lomesh Vadhankar

==

What is compensation for flow ? Why we use compensation ? What are the factors of different compensation ? We not use then what problems may happen ?

0 88

I have observed in field instrumentation work... I remove the fuse of an analog transmitter then it shows 7.75 kg/sq cm (which is practically wrong value)in DCS and when put the fuse it shows 0 in dcs. Then cheach the field transmitter termination and found moister. clean that and then it shows 1.1 kg/ sq cm which is right value. Please describe the above phenomenon.

0 74

why is the sleeve of the cable used for? Jindal 2 639

What is the detail function of I/O card in DCS ? Why we dont use the I/O directly with controller?

TCE 1 768

What is defferent betwen ESP &PCP PUMP .HOW IT IS WORK?

0 78

In power plant to measure vibration of a turbine we install sensors. Before install this sensor we have to set gap voltage. What is meant by gap voltage and its use?

0 97

p=hdg,please explain these parameters? 3 881

Types of contol loops 1 200

what is The specifications for oriface instalation 0 48

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I heard that we can use flow transmitter for level measurment also hw it is?

2 584

what is the minimum power (P=VI)to produce a spark? 0 76

i need some objective type questions in instrumentation 0 76

what is mean by process control?

==

Re: why is the sleeve of the cable used for?

Answer# 2

also for protecting the signal carrying conductor from anydamages.

==

Re: What is the detail function of I/O card in DCS ? Why we dont use the I/O directly with controller?

Answer# 1

I/O are required to convert the process value or status in to a formet which can be communicated to the controller and v/v controller to processe

==

Define magnetic flow meter and mass flow meter. 1 742

what is difference between fork type and capacitance type level switch. where it is using

0 62

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LADDER LOGIC Can any body state Logic on following condition Instructions to use 1-XIC 2-XIO 3-Output ONLY Program Push 1st button On - 1st lamp should On Then Push 1st button Off - 1st Lamp Should remain on Push 2nd button On - 1st lamp should Off and 2nd lamp should On Then Push 2nd button Off - 2nd Lamp Should remain on.

2 442

Why we use mmwc unit for pressure 0 355

why pneumatic control signal output is use 0.2 to 1 kg/cm2 Jindal 2 855

We are using Rosemount 5400 series Radar Level Transmitters in all types of Sump Applications having oily water hdrocarbon petrochemical nature. What we are facing the problem frequently is that always getting reading frezzed at some value. If we do power recycling , sometimes it is working . then making same freezing problem. If anybody faced before such type of problem and also having solution , Please give the answer.

Sabic 0 102

Why the industry's standard current standards are from 4mA to 20mA,not from 0mA or any other range?

3 656

what is three element loop 6 914

Explain how thw analog to digital converter works with the circuit diagram

==

: why pneumatic control signal output is use 0.2 to 1 kg/cm2

Answer# 1

Relation between nozzal flapper clearance and back pressure is linear from 0.2 to 1kg/cm2 pressure range

==

What is a PID? 6 851

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Control valve Flow characteristic. How the equal percentege curve form?

5 761

What are the most frequent problem faces with Vortex flow meter?

0 82

what is the use of impulse line in AFBC boiler , WHY WE CONNECT IMPULSE LINE TO TRANSMITTER , DRFT GAUGE ETC ????????

Jindal 5 1038

what is cold loop? difference between hot and cold loop? 0 88

Tell me the field calibration procedure step by step with diagram of temperature transmitter, temperature indicator, flow indicator, level indicator, control valve, thermocouple, pressure indicator (digital & analogue).

1 835

Tell me the field calibration procedure step by step with diagram of pressure gauge, pressure switch, pressure transmitter, temperature switch, level switch, flow switch, flow transmitter.

0 137

i have 20 kw motor & my vfd drive capcity is 18 kw if possible to use 20kw motor on this vfd?

2 384

on interface level transmitter model(RTG3302-EMERSON) What is threshold valve how can we select correct threshold value T1,T2,T3,T4 When interface water & hydro carbon

0 78

what is Green field /brown field exposure in chemicals /oil /petrochemicals /refineries /paints /speciality chemicals /gas /FMCG /glass industry

0 126

What pressure results for a flow transmitter of range 0- 180t/h in the dcs and 0-301mbar in the field using square root extraction. Kindly also suggest formulae for the percentages 0,25,50,75,100?

==

e: what is the use of impulse line in AFBC boiler , WHY WE CONNECT IMPULSE LINE TO TRANSMITTER , DRFT GAUGE ETC ????????

Answer# 2

transmitter has a sensor which has a temperature withstandaround 150c but actually steam line is more than 500c thistxt. cant withstand so a condensate pot is available in txt.

impulse line are connected to that pot through that a colddm water is poured and txt. taken in line when steam comesit gets condenses in that pot itself so sensor will not beaffected

==

: how the 2.5bar pressure able to control the 40bar steam

AnswerThe 2.5 bar used to control 0 Bipinchandra

# 4 the valve acts on the Diaphragm. Now the area of the diaphragm is Large and thus the Force Per Unit Area acting on the stem is very much greater than the Process pressure of 40bar. Thus it is not difficult to control this process pressure with the given 2.5 bar air supply to the control valve.

Is This Answer Correct ? 3 Yes 2 No

Ravalia.

Re: how the 2.5bar pressure able to control the 40bar steam

Answer# 5

Mr. Bipinchandra is right but there are more possibleanswers to this. 1) what is the differential pressure acrossthe valve? the pressure of steam might be 40kg but thepressure of steam across the valve might not 40kg. 2) theuse of balanced plug in control valves allow us to controlhigh pressure fluids with minimum actuator force.

Is This Answer Correct ? 3 Yes 0 No

0 Waseem Ahmad

Re: how the 2.5bar pressure able to control the 40bar steam

Answer# 6

according to the formula P=F/A

Actually we are applying the 2.5 bar pressure to the diaphram actuator. By increasing the area of diaphram we can increse the force acting on the diaphram and that muuch of force is more enough to actuate the stem movement.even though 40 bar pressure is applied only to the small area(plug of the control valve).the force actiong on it will be very small

==

Question Asked @ Answers Views select

Please send the all question with answer related for interview.

0 42

difference b\w a transducer and a sensor 2 635

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how the 2.5bar pressure able to control the 40bar steamThirumalai-Chemicals

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2 723

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0 74

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0 93

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1 258

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Ramco 3 935

i have one temperature TX in my loop check time once i was remove elament temp gose maximum then i am conect corectly but still now temp showing maximum what can i do this problem?

==

what is difference b/w tube and pipe ?

Answer# 3

tubes r those which is used for heat transfer in a heatexchanger and pipe is one out side heat exhanger not usedfor exchanging heat but used for

transportation of fluid or gas

==

why 8bit microprocessor referred as 2^16? 2 363

hi friends,im an instrumentation and contol engg student,can u hlp me of suggsting barc written question paper,my id is [email protected], cel no.9563591747

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Why DP level transmitter preferred for closed vessels and Radar level transmitter for open tanks??

2 727

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0 97

what is the difference between Feedback controller and Feed forward controller. and when it is to be used.

3 788

In split range control, we will control 2 outputs with time interval. Eg :(with 4-20 ma signal, for 4-12 ma we are operating one control instrument like valve & for 12-20ma we are operating other control instrumet (other valve). If we get a signal of 15ma to first instrument (Valve 1), what will happened to the first valve, and if we get signal above 20 ma to 2 valve what will happened ?

2 434

why the discharge pressure of ID fan showing negative at fan running condition.(boiler operating condition.)

4 540

I want to measure and control level in tank of size 10*5 filled with gasoline, so plz give me the solution with clear details. how to select transmitter and sensors.

0 48

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0 141

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1 453

In oil & gas industries and petrochemical industries, there are classification of zones like zone 0, zone 1, zone 2. Is there any differences in voltages or power supply supplied for the process instruments, control instruments depending on the zones

0 210

In 2 wire transmitter 1 wire is used for power and other is used for signal( 4-20)ma In 4 wire transmitter 2 wires are used for power and 2 wires are used for signal (4-20)ma . but my question is "what is the criteria or parameters we have to consider while selecting these transmitters for eg( distance, safety zones etc.

1 319

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0 146

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0 44

why 4ma show higher zero ? i have transmiter flow renge 0-1000 m3/h but 4 ma show in monitoring 200 m3/h and 20 ma show 1000 m3/h i want when 4ma show 0 m3/h and 20ma 1000m3/h

==

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3 1420

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Samsung 2 617

What is deffrence between Battery and capacitor Siemens 3 1243

control modes Vedanta 1 549

tell me the field & lab calibration procedure step by step with diagram of pressure gauge, pressure switch, pressure transmitter, temperature switch, level switch, flow switch, flow transmitter, temperature transmitter, temperature indicator, flow indicator, level indicator, control valve, thermocouple, pressure indicator (digital & analogue),

0 139

if i change range of flow transmitter in th field then does it need to change range in dcs?

3 587

how to calculate flow range in DP txKarnataka-

Power 0 212

how to calibrate steam control valve in steam turbine 0 144

How to isolate a DPT from line in the condition that process must not be disturbed,and process is also critical and no bypass is available.?

Descon 2 576

what is hart communicater? can u give brief explanation about this issue?

3 789

can any one help me to get bel probational engineers sample question papers. I have applied for it.

==

What is micromotion transmitter? What is the porpose of using this transmitter?

Answer# 1

I think you are talking about the Vendor name "Micro motion" which manufacture the Coriolis meters.This instrument measures the mass flow rate of fluid by 2 parallel vibrating tubes

==

control modes

Answer# 1

control modes are two types 1. continuous control modes in that three types are there I. P-controller II.I-controller III.D-controller and combination of these modes2. discontinuous control modes in that two types are there I. two position control modes II. three position control modes

==e: How to isolate a DPT from line in the condition that process must not be disturbed,and process is also critical and no bypass is available.?==

==What is deffrence between Battery and capacitor

Answer# 1

Capacitor is not a constant source of voltage and current aswell.It shows transient behavior of current and voltage whenapplied to a some resistance or load and it dischargesalmost instantaneously that does not serve the purpose thusbatteries are used

==

what is difference b/w the solinoid volve and autodrain? 1 581

what is Mv with respect to temprature in thermocouple 2 508

How to carry out hot loop checking of closed loop pf temperature control valve & temperature transmitter?

2 1104

What is the SCAN time of a DCS/PLC? What is the typical value for scan time of DCS and PLC?

Essar 3 1644

how can you change unit of totalizer in siemens mag 5000 flow meter?

PowerTech 1 517

Basically iam Instruemntation Engineer, but Iam interested in Instruments design engineering, so plz guide, is there any course, training or Softwres to become Instrument design engineer??.

Honeywell 0 75

what is meant by control valve sizing? 3 830

Can Any body tell me how to check Modbus Settings in ER300N L&T trivector meter?

0 113

whats the working principle of level transmeter? 5 2591

what's the criteria of using over range protector when installing Pressure Gauge

1 412

what happen if i increase height of displacer type LT.accuracy or sensitivity are affected.why?

Essar 0 117

Hi, I'd like to know the purpose of MOS (maintenance override switch). At site, these switches are installed in a stanchion with the transmitter (connected to ESD). thank you.

1 461

What is the main difference between the terms instrumentation and Automation?

5 966

What is an antisurge control system, how it works? 3 1003

i am having information technology branh ....... can i prepare for psu exam

== What is the SCAN time of a DCS/PLC? What is the typical value for scan time of DCS and PLC?

Answer scan time is the time taken by DCS/PLC to read inputs,

0 Vicki

# 1 execute program and as per input/logic update outputs accordingly. PLC scan time depends on no. of inputs, outputs and program size(total memory used, heap size). so it may be different for different program(PLC). less scan time means faster PLC action. scan time is mostly in mili seconds, from 2ms onwords.

Is This Answer Correct ? 13 Yes 1 No

Re: What is the SCAN time of a DCS/PLC? What is the typical value for scan time of DCS and PLC?

Answer# 2

scan time means the time required to read the inputs,execute the program and generate the output this is called scan time the scan time is usually in milli seconds to nano seconds

==

what is difference b/w the solinoid volve and autodrain? 1 581

what is Mv with respect to temprature in thermocouple 2 508

How to carry out hot loop checking of closed loop pf temperature control valve & temperature transmitter?

2 1104

What is the SCAN time of a DCS/PLC? What is the typical value for scan time of DCS and PLC?

Essar 3 1644

how can you change unit of totalizer in siemens mag 5000 flow meter?

PowerTech 1 517

Basically iam Instruemntation Engineer, but Iam interested in Instruments design engineering, so plz guide, is there any course, training or Softwres to become Instrument design engineer??.

Honeywell 0 75

what is meant by control valve sizing? 3 830

Can Any body tell me how to check Modbus Settings in ER300N L&T trivector meter?

0 113

whats the working principle of level transmeter? 5 2591

what's the criteria of using over range protector when installing Pressure Gauge

1 412

what happen if i increase height of displacer type LT.accuracy or sensitivity are affected.why?

Essar 0 117

Hi, I'd like to know the purpose of MOS (maintenance override switch). At site, these switches are installed in a stanchion with the transmitter (connected to ESD). thank you.

1 461

What is the main difference between the terms instrumentation and Automation?

5 966

What is an antisurge control system, how it works? 3 1003

i am having information technology branh ....... can i prepare for psu exam

==how we can calibrate an Interface level transmitter online L&T 2 837

What is the DIfferences between SMART transmitters and PROFIBUS DP/PA Transmitters?

1 635

What is the difference between local indicator(flow) and flow indicator?

2 712

how to install the Ph and Conductivity analyser? is there are any procedures which has to be maintained.

2 465

how can we calibate ph meter. how can we calibrat conductivimeter how can we calibrat massflowmeter & it s working.

0 126

1,why we use 4-20 ma output of all instrument qhy not use 0- 20, 2,what is the different between PLC & DCS. 3,how can we meaure maximum span of new flowmeter if not given any information.

2 851

What is NAMUR standard and why its allways reletad with Sollenoid

0 1614

how is work pressure switch& level switch?what is the principle of this?

Binani 0 121

WHAT IS LOOP CHECKING ? 5 1359

what does ip65 signify??what is its NEMA equivalent??? 1 547

what is interface level and how it is calibrate? 0 161

I am going to attend a recruitment drive by Schneider in 2 weeks. They have a technical test in the beginning. I would like to know what are the areas i should concentrate on while preparing for the test. My major is Electronics and Instrumentation.

1 283

how can i calibrate I/P converter 3 1102

what is the principale of vortex flow meter.India-

Glycols 5 723

FOR CO/CO2/O2/NOX applications which of the following manufature is best? and what is the basic principle of gas analysers? ABB/YOKOGAWA/EMERSON/SIEMENS/TELEDYNE/THERMOFISHER

== how we can calibrate an Interface level transmitter online

Answer# 1

First fill the tank full with lowspecific gravity fluid and adjust it to zero .then fill the tank full with high specific gravity fluid then adjust the span of the transmitter.

==

what will be the principle & application of dissoled oxygen analyzer at wast water treatment plant at oxidation basin & how it work?

1 476

How a oxygen sensor & analyzer work at boiler or furnace, whats the principle & science is beyond this,How O2 sensor sence & convert signal & move toward analyzer & analyzer show reading in percent?

2 628

How a conductivity sensor & analyzer work at boiler, whats the principle & science is beyond this,How conductivity sensor sence & convert signal & move toward analyzer & analyzer show reading in percent? also what is temperature compensate option in conductivity analyzer

0 115

How a pH sensor & analyzer work at waste water treatment plant, whats the principle & science is beyond this,How pH sensor sence & convert signal & move toward analyzer & analyzer show reading in percent? also what is temperature compensate option in analyzer

1 656

What is the difference b/w EMF, voltage & potential difference?

1 484

what is dedband in instrumentation ? 3 789

Why we use 4 - 20 ma? ONGC 2 1650

can anyone tell me about the basic concepts to consider before to start a PLC panel wiring

ABB 0 66

role of electrical engineer in the instrumentation industry 1 460

Instrumentation engineer please reply me,I am electrical engineer ,what is the future in instrumentation dept {presently working (P&ID) Design} for me,whether good future for me as instrumentation department.what side can i get job in future

3 373

how the 4 to 20 mA signal goes to any controller/indicator,and what is the role of voltage ,12/24 and how to do connection of it, in controller.

0 82

why do we use 4-20 ma current why cant o-20ma 4 1478

can i use 1 sq mm insted of 1.5 sqmm cable cable length 600 mts under ground laying Cable carrying 24 vdc 4-20ma current

2 692

who to convert dc to ac ONGC 3 1230

how we calculate the range of flow from a dp?i mean if we have a dp,3810mm h2o.how much flow ranges we can use for this DP?

==tivated ). An example will be very helpful..thank you. 1 690

How we can check the 2 wire proxy switch? & how it is connected to DI MODULE OF PLC?

0 83

how can we caliberate interface level troll Grasim 2 1911

how to design orifice plate?what is the equation? 0 159

what is the difference between Ethernet unmanaged and managed Switch?

2 436

what is RPI and NUT in controlnet networx. what happen if we are increase the NUT of controlnet networx?

Schneider 1 659

What is the difference between HMI and Scada? Schneider 3 1076

What the basic of communication? Schneider 4 587

what is flow and flowrate? definate and diffrentiate it? pls post a valid ans thanks in advance

Qatar-Gas 2 860

give eg of how I/P is used in control loops 0 76

WHAT IS SMART SENSOR AND DIFFERENT B/W SMART SENSOR AND SENSOR??? PLS GIVE ME ANSWER AS SOON AS POSSIBLE.....

1 498

why we are using digital signals for I/O & how to measure this signals is getting or not ?

0 80

what is the full formof HART 6 953

what are the pinciples & units of flow, level, temperature, pressure, quality.

1 550

Is that Speed Probe and Vibration Probe sensors are same,if yes what is the diff b/w them?

==e: Why CT’s shall not be kept open?==what difeerent between HART and BRAIN? 1 570

when we calibrate the DP transmitter at that time which matrial we used in pressure pump?

4 506

why thermocouple called thermocouple? 3 617

How to calibrate DP tramitter in flow measurement application? consider my range of flow is 0 to 2000 kg/hr ? please give calculation of , How much pressure applied on low pressure side and high pressure side please give detail of calculation .... It so important for me please reply as soon as possible

0 110

what is the different between plc and dcs ? I know full name of this two but I want to know what structure and working style and speed I/O capacity and controller

2 538

difference?

What is Alpha & Beta fctors related to Orifice Plate & its relation with flow?

0 71

we have level transmitter for h2s04 storage tank capacity 10k ,always there are failure of transmitter due to failure of magnetic floats ,please come up with solutions at the earliest.

TechNova 0 53

how can we calibrate the differential pressure transmitter by using HART communicator

5 1832

Dear friends, I have a question: We work on a project which has some boilers to provide steam for desalination unit. The boiler area is safe and the only hazard source is the fuel lines of boilers. I want to know according to NFPA standard which type of instrument should be selected on the fuel line: Eex Type or Non-Eex type? Thanks in advance

1 277

If mVolts can drop by resistance of wire as compare to mA, then how thermocouple mV reaches in CCR as accurate value?

5 792

What is a PID controller and how can it to applied to our everyday life?

4 929

can anyone can let me know in Eurotron Micro cal 2+ calibrator in milli amps source mode we are not able to get 20 milli amps output it only produces 1.52 milli amps out, but display shows increase in milli amps , and err6 displays, let me know how to remove the err 6.

0 99

what is a mapping in plc & dcs Arctern 1 924

what is the standard of determining opening/closing time of Motor Operated Valve?

0 160

what is the difference between(Flame proof/Explosion proof)& Fire proof instruments.Both are same or different & if different in which way because the transmitter which have approved ATEX flame proof enclouser but it use PTPE O ring & PTFE Head Gasket,so its (fire safe/fire

4 1078

proof)????????

== how to test rotor &stator earth fault in turbine

Answer# 1

STATOR EARTH FAULT PROTECTION :Setting : 70% Time - 5 Sec.Normally the generator stator neutral operates at apotential close to ground. If a faulty phase windingconnected to ground, the normal low neutral voltage couldrise as high as line-to-neutral voltage depending on thefault location. Although a single ground fault will notnecessarily cause immediate damage, the presence of oneincreases the probability of a second. A second fault evenif detected by differential relay, may cause serious damage.The usual method of detection fault is by measuring thevoltage across the secondary of neutral groundingtransformer (NGT). Here are two over lapping zones to detectstator ground faults in a high impedance grounded generatorsystem, the two zones are put together cover 100% statorwinding for earth faults. A fundamental frequency neutralover voltage relay covers about 0-95% of the stator zonalwinding for all faults except those near the neutral.Another third harmonic neutral under voltage relay covers

remaining 96-100% of the stator zone 2 winding on neutral side.Relays acted : a. Flag operation at Protection panel.b. Acting of Master relayc. Indication at Annunciation Panel.Consequences : a. Tripping of 220KV breakerb. Tripping of Field breakerc. Stop command to Turbine thro’ Mark-IVStatus : a. Unit is at coasting down.

ROTOR EARTH FAULT PROTECTION (64R) :Settings : Less than 80K ohmAny rotor field winding of the generator is electricallyisolated from the ground. Therefore the existence of oneground fault in the field winding will usually not damagethe rotor. However the presence of two or more ground faultsin the winding will cause magnetic and thermal imbalanceplus localized heating and damage to the rotor metallicparts. The rotor earth fault may be caused due to insulationfailure of winding or inter-turn fault followed by localizedheat.Relays acted : a. Flag operation at Protection panel.b. Acting of Master relayc. Indication at Annunciation Panel.Consequences : a. Tripping of

220KV breakerb. Tripping of Field breakerc. Stop command to Turbine thro’ Mark-IVStatus : a. Unit is at coasting down

== Re: how many types of thermocouple cable are? give the name of each type.

Answer# 1

There are there types of cables is in the Thermocouple.

1.Bare Thermocouple wire.

2.Duplex Insulated Thermocouple Wire

3.Metal Sheathed Thermocouple Wire

1. Bare Thermocouple wire is without any insulation. normally it is sold on a spool and ordered as a pair. usage is typically for making a small thermocouple in applications requiring special considerations.

2.Duplex Insulated Thermocouple Wire

Duplex Insulated thermocuple wire is probably the most common type of thermocouple wire. The type of thermocouple, insulation, and size are all some of the parameters considered for the application.

3.Metal Sheathed Thermocouple Wire.

Metal sheathed Thermocouple wire is thermocouple wire that is surrounded by insulation material, typical magnesium oxid, and enclosed in a metal sheath. A key feature of this type of wire includes the ability to withstand vibration, high temperatures and pressures

==: what should be minimum length and size of impulse line for steam flow orifice and feed water orifice

==Re: I saw one P&ID 6" control valve has been connected with 8" process line, and 2" valve also connected in parallel with 6" valve. why the 2" valve connected in parallel, Is there any technical reason. please clarify. With Regards-Kittu

Answer# 2

above answer is split range controller. what is a split range control? two control valves are controled by a controller is split range. for eg: 50% of controller out put both of the valve will be close condition , see below table.

% input Valve A opening %, Valve B opening&0 0 10025 0 5050 0 075 50 0100 100 0

but in your question on 2" valve is connected parrallel with 6" Control valve. means for the bypassing 6" control valve, they are using 2" valve.

for technically it is very very improtant. becasue at the time of maintance of the control valve, there will be no disturbance in process

==