Ctrl Sys Lab Manual

CHARACTERISTICS OF SYNCHROS

AIM:

To study the characteristics of synchro-transmitter and synchro receiver.

APPARATUS:

1. Synchro-transmitter and Synchro receiver.

2. Digital multimetre.

THEORY:

A synchro is an electronic magnetic transducer commonly used to convert angular

position of shift into an electrical signal.

A synchro system is formed by interconnection of the devices called synchro-

transmitter. They are also called as synchro pair. The synchro pair measures & compares

two angular displacements and its output voltage is approximately linear with angular

displacement of axis of both shaft.

Working:

Synchro-transmitter is applied as input to stator coils of electric transformer. The

rotor shaft connected to the load whose position as to be maintain of the desired value,

depending on the current position has to be of rotor & applied emf on the stator. An emf is

induced on rotor winding. The emf can be measured and used to drive the motor so that

the position of the load is correct.

The rotor of control transformer is made cylindrical so that the air gap is practically

uniform. this feature of control transformer minimizes the change in the rotar impedance

with the rotation of the shaft.

PROCEDURE:

Synchro-transmitter:

1. Connect main supply to system with the help of cable provided ,don‟t connect any

patch cards to the terminals marked S1, S2, S3.

2. Switch on the main supply for the main unit.

3. Starting from zero positon , note down the voltage between stator winding terminals

i.e Vs1,s2,Vs2,s3&Vs3,s1 in sequential manner.

4. Enter reading in a tabular form & plot the graph at angular position at error

voltage for all the 3-phase circuits.

5. Note down the „0‟ position of the stator rotar. Consider with Vs3,s1 voltages equal to

zero voltages.

6. Don‟t disturb this condition.

Synchro-transmitter receiver pairs:

1. In this condition S1, S2, S3 terminals of transmitter to S1, S2, S3 terminals of

receiver by patch cards provide.

2. Switch on SW1 & SW2 and also switch on the power supply.

3. Move the pointer i.e, rotor position of synchro receiver T2 in steps & so dynes &

observe the new rotar position , observe that whenever the rotar position is rotated

the transmitter rotar follows of their positions are in good agreement.

4. Enter input angular position & output angular position in tabular form.

5. Plot a graph.

PRECAUTIONS:

1. Avoid loose connections.

2. Readings are taken without parallax error.

RESULT:

TIME RESPONSE OF SECOND ORDER SYSTEM

AIM:

To observe the time response of second order system.

APPARATUS:

1. Linear system simulation.

2. CRO

THEORY:

The response is given by the system which is the function of the time to applied

excitation is called the time response of control system.

Similarly final value is achieved by the output also dependent on different factor

like friction mass of the moving element etc.

The output varies during the time it taken to achieve its final value is called

transient response.

The time require to achieve the final value is called transient response. This can be

defined that part of the time response which delay to zero.

It is the time required for the response to reach its peak value.

Tp=π/ωd= π/ ωn √1-ξ2

PROCEDURE:

1. Choose the suitable second order system configurations.

2. Apply peak to peak square voltage wave form on the tracking factor for different

values of „k‟.

3. Obtain peak over shoot, settling time, rise time, steady state error from tracking

paper. Calculate ξ and ωn.

Theoretical calculations:

K=10, K1=10 K3=50

T1=T2=1ms

C(s)/R(s)=k. K1/S. K3/(S T2+1)

Tr= π- θ/ ωd θ=in radians.

θ=tan-1

(√1-ξ2/ ξ)

ωd= ωn√1-ξ2

Tp= π/ ωd

Ts= 4/ ξ ωn

Mp=e-πξ

/√1-ξ2

Td=1+0.7 ξ/ ωn

PRECAUTIONS:



RESULT:

ROOT LOCUS & BODE PLOT USING MATLAB

AIM:

To construct the root locus & bode plot by step by step procedure and to verify

them using mat lab soft ware for a given transfer function.

APPARATUS:

1. Mat lab soft ware

THEORY:

Mat lab is a highly performance language for technical computations. It integrates

training computation visualization &programming in an easy to use environment where

problem and solution is expressed in familiar mathematical notation.

Mat lab ia an interactive system whose basic element is an array that does not

require dimensioning the mat lab stand for matrix laboratories. It is written to provide

easy to accesses matrix soft ware development program by LINK PACK and LIBRARIES.

Mostly used commands

Bode (num,den)

Bode (A, B, C, D)

Bode (syn)

Bode returns a frequency response of a system in matrix magnitude phase „ωn‟

ofplot is drawn on the screen. The matrix magnitude & phase angle contained in frequency

response of a given system evaluated at frequency points.

STAs

STAE SPACE REPRESENTATION OF TRANSFER FUNCTION USING

MATLAB

AIM:

To obtain state space model for classical transfer function using mat lab.

APPARATUS:

1. Mat lab soft ware

THEORY:

Mat lab is a high performance language for technical computing. It integrates

computation visualization &programming in any easy to use environment where problem

&solution are expressed in familiar mathematical notation.

Mat lab is an inter active system whose basic data element is an array that doesn‟t

require dimensioning analysis of control system.

1. Classical method.

2. Modern method.

If „n‟ element of the vector is a set of state variables then the vector matrix

differential equation is called “state space equation”.

State space analysis is very useful technique of analysis the control system. It is

based on the concept on the state and is applicable to linear time varying & non-linear

memo system.

CHARACTERISTICS OF AC SERVOMOTOR

AIM:

To draw the characteristics of ac servomotor.

APPARATUS:

1. Two phase AC servomotor speed control and transfer function steady trainer.

2. Patch cards.

3. Voltmeter (0-20v)mc.

THEORY:

It is two phase induction motor. It mainly divided into 2 parts.

1. Stator.

2. Rotor.

The stator carries 2 windings uniformly distributed &displaced by 900 in space.

One winding is called main or fixed windings. It is excited by the constant voltage

AC supply. The other winding is called control windings. It is excited by variable voltage

control is obtained by AC servo amplifier.

This voltage is 900 out of phase with respect to reference winding voltage. It is

obtained to rotate magnetic field. This is the construction of ac servo motor.

Rated voltage, E2=E1

Ktm=blocked rotor test at rated voltage/control voltage

Ktm=T0/ E2

M= - blocked rotor torque/no load speed= -T0/ W0

PROCEDURE:

1. Connect G1K1 of pulse isolation output to G1K1 of SCR1.

2. Connect G2K2 of pulse isolation output to G2K2 of SCR1.

3. Vary the control voltage plot & set the rated voltage to control phase winding.

4. Apply the load on the motor step by step up to the motor will run at zero rpm.

5. For each step, note the reading as shown the table „1‟.

6. To calculate the torque value.

7. Plot a graph ,speed Vs torque.

PRECAUTIONS:



RESULT:

CHARACTERISTICS OF DC SERVOMOTOR

AIM:

To draw the characteristics of dc servomotor.

APPARATUS:

1. Dc motor.

2. Multi meter.

3. CRO.

THEORY:

In this motor, the controlled signal obtained from the servo amplifier is applied to

the field winding. With the of constant source, the Ia is maintained constant.

Assumptions:

1. Ia is maintained.

2. Φ=kfIf.

In armature controlled dc motor, field current If is taken from the field coils &the control

voltage is obtained from the servo amplifier is given to the armature circuit.

PROCEDURE:

1. Before switch on the unit

i) EXT/INT switch must be in INT mode.

ii) Integral open or close switch in open mode.

iii) Signal condition switch in open mode.

iv) Interface the motor supply sensor with module.

2. Initially pulse on/off switch should be in off module.

3. Switch on the unit, keep the pulse on/off to on mode.

4. Set the proportional gain Kp at minimum.

5. Set Vref=1v slowly increase the proportional gain by means of Kp adjustment plot

that motor runs.

6. Observe the optical speed sensor output at F through CRO & measure the period of

the pulse. Measure the speed feed back voltage Vf using a multi meter .

7. Vary the speed of the motor , by varying the proportional gain in steps , for each

step note down the speed & measure the speed feed back voltage is tabulate the

readings observe the frequency of the pulse at high through CRO.

8. Reduce the speed & switch OFF the power.

9. Plot the graph Vf Vs w characteristics & calculate the speed feed back gain as

shown.

FORMULAWS:

Vf =KW.W

KW = Vf / W

W= 2ΠN/60

PRECAUTIONS:



RESULT:

STUDY OF LEAD AND LAG COMPENSATION NETWORK

AIM:

To study lead and lag compensation network and plot the graph.

APPARATUS:

1. Function generator.

2. Ac voltmeter.

3. Phase angle meter.

4. Connecting wires.

THEORY:

Consider a single phase lag network. The s-plane representation of

lag compensation every position .Control system is designed for a specific

application has if met certain application performance characteristics. The

gain is the first setting and first step.

For adjusting the satisfactory performance in many practical

causes how ever the adjustment of gain alone may provide sufficient

alternation.

In adjusting the satisfactory performance in many practical

causes however the adjustment of gain alone may provide.

PROCEDURE:

1. Switch ON the Ac main supply.

2. Sw1 ,Sw2 and Sw3 should be in ON position.

3. Observe that input and output potentiometer come in alignment.

4. Keep the gain probe in almost maximum.

5. Take the input potentiometer to the starting position i.e x-axis‟s to zero

position.

6. Vary near to zero position to the output potentiometer will as fallows

the input potentiometer the null detector null position.

7. Enter the observation in the tabular form below you may repeat the

observation with lower amplifier gain to observation with low i.e max

gain you may note down that the output indicates sustained oscillations.

TABULAR FORMS:

Lag compensation network:

Frequency

Practical Theoretical

Phase angle Vo /Vin Phase angle Vo /Vin

Lead compensation network:

Frequency

Practical Theoretical

Phase angle Vo /Vin Phase angle Vo /Vin

MODEL CALCULATIONS:

For lag:

T = (1/RC) / √W2 + (1/RC)

2

Φ = Tan ˉ1 (WRC)

For lead:

Φ = Tan ˉ1 (1/WRC)

Vo/Vin = R/√R2 + (1/w

2 c

2)

PRECAUTIONS:


2. Readings are taken with out parallax error.

RESULT:

TRANSFER FUNCTION OF DC GENERATOR

AIM:

To derive the transfer function of separately excited Dc shunt generator.

APPARATUS:

S.NO APPARATUS RANGE TYPE QUANTITY

1. Voltmeter

2. Ammeter

3. Rheostat

4. Taco meter

THEORY:

Transfer function of a system is the ratio of Laplace transform of

output to Laplace transform of input with initial conditions set to zero.

When a physical system is analyzed a mathematical model is

developed by writing different equations of various physical laws governing

transfer function is as fallows .

To write different equations for the given system. By Laplace

transforms reduce the equation involve the terms.

To obtain the ratio of transfer function as fallows. To obtain the ratio of

transformed output to input properties of transfer function as fallows.

The system stability to be described in terms of location of roots of

transfer function.

PROCEDURE:

1. Connect the circuit as per the circuit diagram.

2. By varying the rheostat, run the motor at rated speed.

3. Slowly vary the potentiometer , take the voltage across generator output

terminals.

4. Draw the occ to the above readings.

5. Draw the tangent to occ.

To find Rf:


2. Apply the voltage of Ac to find impedance of field with different readings

of voltmeter & ammeter.

3. By using time constant , generator is constant ,the transfer function of

generator is

G(S) = Kg / Rf(1+s Tg)

To find Zf :


2. Apply voltage to Dc to find the resistance of field.

3. Slowly vary the potentiometer , take the readings of voltmeter &

ammeter to find Zf.

TABULAR FORMS:

S.NO Voltage Current

To find resistance :

S.NO Voltage Current Resistance

MODEL CALCULATIONS:

XL = √Zf 2 – Rf

2

Kg = OA/OB

L = XL /2Πf

Kg = Slope of tangent of occ

G(S) = Kg / Rf(1+s Tg)

Tg = L/ Rf

PRECAUTIONS:



RESULT:

PROCESS CONTROL SIMULATOR USING P – CONTROLLER

AIM:

To observe the time response of closed loop second order process with

proportional gain.

APPARATUS:

1. CRO

2. Trainer kit.

THEORY:

The has one major advantage, namely that there is considerable

deviation present at all time. As deviation should operate the system ,this

implies that sensitivity is low.

This sensitivity is defined in terms of the proportional brand. This is the

range of values of deviation that causes the controller output to cover its full

operating range. This is often expressed as a percentage such that 100%

proportional band nears that the full range of outputs of measuring systems

causes the controller to operate over its full range.

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Set the process fast/slow switch in fast position.

3. Keep the set value pot to zero.

4. Apply a square wave signal of 2Vpp at around 50hz.

5. Alternately display in the oscilloscope , set value disturbance point &

measured value from the point Pv.

6. Repeat all the above steps with the percentage proportional band 50 %

& 40%

7. Observe the response & find the peak over shoot , rise time , damping

ratio & settling time and also tabulate the readings.

TABULAR FORM:

%P.B MP RISE

TIME

PEAK

TIME

DAMPING

RATIO

SETTLING

TIME

PRECAUTIONS:



RESULT:

PROCESS CONTROL SIMULATOR USING P-I CONTROLLER

AIM:

To study the response of P-I controller.

APPRATURS:

1. Trainer kit

2. CRO

THEORY:

The proportional control to maintain a stable system the gain level is

such that the system is incentive to deviation below the certain level. In an

ideal system , the measured value & the set value should be the same under

steady state condition the deviation should be zero.

Alternative signal to be fed into main amplifier of sufficient size to

provide on output if a steady state deviation exists viz to reduce the offset to

zero. Such a signal can be provided by an integrator which gives a constantly

increasing output for a steady value input . Such an arrangement is known as

proportional + integral controller & should reduced any steady state deviation

to zero.

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Set the process fast / slow switch (sw4) & controller fast / slow switch

(sw3) in fast position .

3. Keep the set value pot at zero position.

4. Apply a square wave of 2Vp-p at around 50hz .

5. Adjust the proportional band control until the system settles with 2-3

over shoots.

6. Now connect the integral section.

7. Slowly reduce the integral action time until the deviation falls to zero .

8. Observe the response & calculate the PB ,Integral time, Mp, Tr & Ts .

TABULAR FORM:

S.NO %P.B RISE

TIME

MP INTEGRAL

TIME

SETTLING

TIME

PRECAUTIONS:



RESULT:

PROCESS CONTROL SIMULATOR USING PID CONTROLLER

AIM:

To study the response of P+I+D controller in a process.

APPARATUS:

1. Trainer kit

2. CRO

THEORY:

The integral control improves the performance of the control

system in some response i.e it reduces the steady state deviation , but has the

disadvantages of slowing down the over all response time.

If a system is required to follow a sudden change in set value this

would give rise to a rapid change in the deviation . Although this deviation

change is rapid the system response rather slowly , so if at this time the

controller output can be boosted the speed of system response will be

improved.

If the deviation is differentiated i.e rate of change measured & a signal

produced proportional to this & then added to the signals from the

proportional & integrator sections , some improvements may results . Such an

arrangement is known as 3-term controller or PID controller.

PROCEDURE:

1. Connections are made as per the circuit diagram .

2. Set the process fast /slow switch(sw4) & controller fast /slow switch

(sw3) in fast position.

3. Apply a square wave of 2 Vp-p at around 50hz .

4. Now patch I & I‟ & adjust the integral time until the steady state

deviation is zero.

5. Now note down the no. of over shoots before the system settles.

6. Now connect D & D‟ & slowly increase the deviation time & note down

the effect of this system response.

7. Observe the response & calculate the PB , Integral time, Mp, Tr & Ts.

TABULAR FORM:

INTEGRAL

TIME

%P.B RISE

TIME

MP PEAK

TIME

SETTLING

TIME

PRECAUTIONS:



RESULT:

CHARACTERISTICS OF MAGNETIC AMPLIFIER

AIM:

To study the control characteristics of magnetic amplifier.

APPARATURS:

1. Magnetic amplifier circuit.

2. Patch cards.

3. Input voltage 230v, 50hz,1-ph

THEORY:

Magnetic amplifier is a device consists of combination of saturation

reactors , rectifier & conventional light fits used to secure control on

amplification.

Load winding is connected in series with the load one control the

current by changing the vector of the coil with the help of DC control current

. The load current can be controlled still saturation of reaction is approached .

The property of storable read , used in magnetic amplifier.

PROCEDURE:

a) Series controlled magnetic amplifier:

1. Keep slide switch in position D which will be indicated by a

indicator .

2. Keep control current setting knob at its left position .

3. With the help of plug in liner , connect the terminals on the front

panel of unit.

i) Connect AC to A1.

ii) Connect B1 to A2.

iii) Connect B3 to L.

4. Plot the graph of IL VS IC.

b) Parallel controlled magnetic amplifier:

1. Keep slide switch in position D which will be indicated by

indicator .

2. Keep Ic settling knob at its position of external left position which

ensure o control current.

3. With the help of plug links , connect following terminals on front

panel.

a) Connect AC to A1.

b) Connect A1 to A2.

c) Connect B2 to L.

d) Connect B1 to B2.

4. Now gradually increasing the control current by rotating control

current.

c) Self saturated amplifier:

1. Keep slide switch in position E.

2. Keep control current setting knob at its external left position .

3. With the help of plug links connect,

a) Connect Ac to C1.

b) Connect A3 to B3.

c) Connect B3 to L.

4. Plot the graph of load current Vs control current.

TABULAR FORM:

S.NO INPUT CURRENT OUTPUT CURRENT

PRECAUTIONS:



RESULT:

Ctrl Sys Lab Manual

Documents

familiar mathematical notation

avoid loose connections

root locus

lag compensation network

process control simulator

external left position

steady state deviation

called transient response