A LaymanA Laymans Guide to HARTs Guide to HART Communications
with Communications with FIELDVUEFIELDVUE InstrumentsInstrumentsJ
eff VonAhnenRick OsbornFIELDVUE Technical SupportEmerson Process
ManagementFisher Valve DivisionMarshalltown, IowaPage
2PresentersPresentersJeff VonAhnenFIELDVUE Technical SupportRick
OsbornFIELDVUE Technical SupportPage 3Digitally Communicating
FIELDVUE Digital Valve ControllersDigitally Communicating Digitally
Communicating FIELDVUE Digital Valve ControllersFIELDVUE Digital
Valve Controllers Accurately control the valve Accurately control
the valve Transmit device health Transmit device health Predict
future valve performance Predict future valve performancePage
4FIELDVUE Instruments Designed for DiagnosticsFIELDVUE Instruments
FIELDVUE Instruments Designed for DiagnosticsDesigned for
DiagnosticsActual Valve TravelInput currentI/P Drive CurrentRelay
positionPort B pressurePort A pressureSupply pressure32 Device
Alert andStatus indicatorsDrive SignalCycle CounterTravel
AccumulatorTriggered PD ProfilePage 5Vast Array of Diagnostics
Available Vast Array of Diagnostics AvailableVast Array of
Diagnostics AvailableIncreasing Diagnostic CapabilityAlert
EventRecord(on-line)(alert events)Network Alert Scan(on-line)(alert
log & trending)Performance Diagnostics(on-line)(graphs,
interpretation)Dynamic Scan Diagnostics(off-line)(graphs,
interpretation)Page 6But it all breaks down if you have HART
Communications issues!But it all breaks down if you have But it all
breaks down if you have HART Communications issues!HART
Communications issues!F1 F2 F3 F4DVC6000: HART TagDevice
DisconnectedRETRY QUITWhat causes such problems?What causes such
problems?What can be done?What can be done?F1 F2 F3 F4DVC6000: HART
TagAccess RestrictedInstrument was takenOut of Service byanother
master.ABORTOKPage 7Topics to be discussed: Topics to be
discussed:Topics to be discussed: What is HART? Request
ResponseHART communications with Primary and Secondary masters.
Burst mode communications. Multiple HART masters and communication
arbitration. What happens when things go wrong. Techniques for
sorting out the problems. What are HART Filters? Review of HART
multiplexers and how their differences can affect HART
communications.Page 8So, what is So, what is HARTHART??Page
9According to the HARTCommunication Foundation Website:According to
the HARTAccording to the HART Communication Foundation
Website:Communication Foundation Website:HART: is a master-slave
field communications protocol was developed in the late 1980's to
facilitate communication with Smart field devices. is an acronym
for Highway Addressable Remote Transducer. makes use of the Bell
202 Frequency Shift Keying (FSK) standard to superimpose digital
communication signals at a low level on top of the 4-20mA, enabling
two-way field communication to take place and makes it possible for
additional information beyond just the normal process variable to
be communicated to/from a smart field instrument. communicates at
1200 bps without interrupting the 4-20mA signal allows a host
application (master) to get two or more digital updates per second
from a field device. due to the phase continuous digital FSK signal
is phase continuous, creates no interference with the 4-20mA
signal. Page 10Overload! Overload! Overload! Overload!Overload!
Overload!OK, lets slow it down a bit Page 11HART HART Physical
LayerPhysical Layer--the electrical signalsthe electrical
signalsPage 12First, what is Analog Control ? First, what is First,
what is Analog ControlAnalog Control?? Milliamp control signal
created by an Analog Output channel. 4 to 20 milliamps represented
0% to 100%. Referenced relative to constant groundsignal. Used to
power coil of wireI/P valve instruments. Goal for Analog Output
cards is to generate an accurate, smooth, steady, ripple-free
signal.4.08.012.016.020.00.0Page 13What is HART communication? What
is What is HARTHARTcommunication?communication? A way to
superimpose a digital communication sinusoidal signal onto the
milliamp control signal. The same basic technology a phone modem
uses to superimpose a digital communications onto an analog phone
signal. The milliamp control signal is not affected by the
bi-directional digital HART signal.(FYI: HART signals as viewed on
an electrical oscilloscope)Page 14What is HART communication? What
is What is HARTHARTcommunication?communication? A different
waveform for a transmitter on an Analog Input channel compared to a
digital valve controller on an Analog Output channel. Depends on
what the 1000 pound gorillais for each kind of channel.Page 15What
is HART communication? What is What is
HARTHARTcommunication?communication? For an Analog Input (AI)
channel, the system provides the 24 volt signal (its 1000 pound
gorilla) and the transmitter controls the milliamp current signal.
So for a transmitter on an AI channel, the HART waveform is
modulation of the milliamp current signal.Analog mASignal2200
Hz1200 Hz"1" "0"+0.5 mA- 0.5 mAPage 16What is HART communication?
What is What is HARTHARTcommunication?communication? For an Analog
Output (AO) channel, the system provides the 4-20 mA control signal
(its 1000 pound gorilla) and the digital valve controller controls
the voltage on the loop. For a digital valve controller on an AO
channel, the HART waveform is modulation of the loop
voltage.TerminalVoltage2200 Hz1200 Hz"1" "0"+0.5 VDC- 0.5 VDCPage
17HART CommunicationsHART Communications--Possible Physical Layer
Possible Physical Layer problemsproblemsPage 18Electricity compared
to water Electricity compared to waterElectricity compared to water
A handy way to think about voltageand currentis to compare them to
water coming out of a hose. The pressure pushing the water out of
the hose is analogous to voltage. The volume of water coming out of
hose is analogous to current. It is easy to push a little volume of
water out with high pressure (squirt gun). It is hard to maintain
high pressure when you are pushing out large volumes of water (fire
hose).volume(current)Pressure(voltage)Page 19FIELDVUE Compliance
Voltage FIELDVUE Compliance VoltageFIELDVUE Compliance
VoltageRequired Compliance Voltage DVC5000 w/ HART: 12.0Vw/o HART:
11.5V DVC6000 w/ HART: 11.0Vw/o HART: 10.5V DVC2000 w/ HART:
9.0Vw/o HART: 8.5VMeasurable Terminal Voltage (typical) DVC5000
@4mA: 10.8V@20mA: 11.0V DVC6000 @4mA: 9.5V@20mA:10.3V DVC2000 @4mA:
8.0V@20mA:8.3VThe DVC takes the available system loop voltage and
regulates it down to the Terminal Voltage values.Page
20Insufficient Compliance Voltage can render the HART signal
unreadableInsufficient Compliance Voltage can Insufficient
Compliance Voltage can render the HART signal unreadablerender the
HART signal unreadable4.0 mA 20.0 mA9.55 0.15 V10.35 0.15 V11.0 V
minimumfor DVC6000System Compliance Voltagewith HART
communicationsAvailable System Compliance
VoltageMeasurableTerminalVoltage11.0 V For a FIELDVUE instrument,
the available loop compliance voltage needs to be at least 0.5
volts above what is needed for the DVCs terminal voltage. If the
voltage droops below this level, the top half of the HART waveform
will get clipped offand HART communication faults will occur. Page
21Electrical noise can mess upthe HART signalsElectrical noise can
mess upElectrical noise can mess upthe HART signalsthe HART
signalsThis includes: High strength Electro-Magnetic Interference
(EMI) (walkie talkie, arc welding, etc). Poor electrical wiring,
shielding, and grounding practices.Page 22 Non-HART compatible AO
channels may view the HART waveform as noiseor AC rippleand may
attenuate it down below size of a valid HART signal. To keep the AO
channel from reacting to the HART signal, a HF300-series HART
Filter may be needed.The host DCS can mess upthe HART signalThe
host DCS can mess upThe host DCS can mess upthe HART signalthe HART
signalTerminalVoltage2200 Hz1200 Hz"1" "0"+0.5 VDC- 0.5 VDCPage
23What is a HART Filter ? What is a What is a HART FilterHART
Filter?? Possibly misnameddoes not do filteringas you would
normally expect from an electrical filter circuit. Acts like a
wallto block HART signals. HART signals existing on the fieldsideof
the HART filter cannot be seen on the systemside.Page
24Troubleshooting hint:You can hear HART signals!Troubleshooting
hint:Troubleshooting hint:You can hear HART signals!You can hear
HART signals! At frequencies of 1200 and 2200 Hz, HART is in the
audible range for the human ear. With a simple speaker / amplifier
and a connection cable, you can eavesdrop on HART traffic. Once you
are familiar with recognizing the sounds of different kinds of HART
signals, this can be a handy troubleshooting tool.Page 25HART
CommunicationsHART Communications--Master Communication
DevicesMaster Communication DevicesPage 26HART is Question Answer
HART is HART is Question Question AnswerAnswer A masterHART device
asks a question to the slavefield device. The slavefield device
immediately answers this question. The slavedevice does not speak
unless spoken to.Page 27HART supports two masters talking to one
slave device at the same timeHART supports two masters talking to
HART supports two masters talking to one slave device at the same
timeone slave device at the same time One master is deemed Primary.
Other master is deemed Secondary. Although both masters hear all
replies from the slave device, they only respond to the reply
directed at them individually. PrimarySecondaryPage 28HART supports
two masters talking to one slave device at the same timeHART
supports two masters talking to HART supports two masters talking
to one slave device at the same timeone slave device at the same
timeRules of HART communication arbitration: Only one HART master
of each gender allowed. Both masters are very polite and courteous.
They alternate taking turns talking to the one slave device. No
interrupting while the other master is talking!Page 29There is a
third way Burst Mode There is a third wayThere is a third wayBurst
ModeBurst Mode A slave device can be configured to provide an
answerwithout having been asked a question. When in Burst Mode, the
slave device replies with the answer to a predetermined HART
command (usually Hart Command 3). This message is an unaddressed
broadcast on the loop to any device who listens for such things
(like a Tri-LoopHART-to-Analog converter). Page 30Burst Mode
Communications Burst Mode CommunicationsBurst Mode Communications
Other masters ignore Burst Modemessages, but must arbitrate around
them. Burst Mode communications get interspersed between Primary
and Secondary master communications. The slave device now becomes
responsible for its portion of the HART communication arbitration
with the other master devices.Page 31HART Command Arbitration HART
Command ArbitrationHART Command Arbitration The smooth interlacing
of HART requests and slave replies to avoid collisionsor
interruptions. It is the responsibility of every device that wants
to contribute in a HART conversation. Usually it is done by master
devices, but is also done by a slave device in Burst Mode. Follows
the cadence:Primary master (question / answer)Burst Secondary
master (question / answer)BurstPage 32HART Communication Rate HART
Communication RateHART Communication RateIt takes about second for
one HART message:(single master shown)Page 33HART
CommunicationsHART Communications--HART CommandsHART CommandsPage
34Typical HART commands Typical HART commandsTypical HART
commandsHART commands come in three categories: Universal commands
Implemented by ALL HART field devices Commands #0 through #32
Common Practice commands Implemented by many, but not all HART
field devices Commands #33 through #127 Device Specific commands
Unique to a particular field device Commands #128 and up Same
command number will mean different things to different field
devices.Page 35Universal HART commands(as defined for a FIELDVUE
Instrument)Universal HART commandsUniversal HART commands(as
defined for a FIELDVUE Instrument) (as defined for a FIELDVUE
Instrument)#0 - Read Unique Identifier#1 - Read Primary Variable#2
- Read Loop Current and Percent of Range#3 - Read Loop Current and
four Dynamic Variables#6 - Write Polling Address#11 - Read Unique
Identifier associated with a Tag#12 - Read 32-character Message#13
- Read 8-character Tag, 16-character Descriptor, and Date#17 -
Write 32-character Message#18 - Write 8-character Tag, 16-character
Descriptor, and DatePage 36Common Use HART commands(as defined for
a FIELDVUE Instrument)Common Use HART commandsCommon Use HART
commands(as defined for a FIELDVUE Instrument) (as defined for a
FIELDVUE Instrument)#33 - Read Four Transmitter Slot Variables#35 -
Write Primary Variable Range Values#38 - Reset Configuration Change
Flag#42 - Master Reset#44 - Change PV Units Code#48 - Read
Additional Status#59 - Write Number of Response Preambles#108 -
Write Burst Mode Command number#109 - Burst Mode ControlPage
37Device Specific Commands Device Specific CommandsDevice Specific
Commands Not listed here - they are Proprietary. Allows for product
uniqueness within an Opencommunication protocol. Used for special
device functionality (diagnostics, etc.).Page 38Format for various
HART commands:Master/Slave/Burst address command byte count status
data checksumCommand 3M 93 03 32 36 02 3 017S D3 03 32 36 02 3 26
00 40 40 80 60 00 27 40 80 60 00 39 C1 B7 E0 00 06 C2 DC 80 00 39
BD 7A 00 00E7Command 33M93 03 32 36 02 33 4 0C 00 00 00 3DS 93 03
32 36 02 332600 48 0C 00 00 00 00 03 00 27 40 80 60 00 00 27 40 80
60 00 00 27 40 80 60 00EBCommand 48m 13 03 32 36 02 48 0 A4s 53 03
32 36 02 48 10 00 40 00 00 08 00 02 00 13 67D4Command 0m13 03 32 36
02 0 0 94s 13 03 32 36 02 0 1400 40 FE 13 03 05 05 01 05 08 00 32
36 023APV SV TV QVExample HART Commands Example HART
CommandsExample HART
Commands1stSlotVariable2ndSlotVariable3rdSlotVariable4thSlotVariablePage
39Device Status byteDevice Status byte Device Status byte Available
with every HART reply message:Bit 7 - Field Device Malfunction
(hardware error or failure)Bit 6 - Configuration ChangedBit 5 -
Cold Power-up (cleared by the 1st HART command)Bit 4 - More Status
AvailableBit 3 - Analog Input Fixed (set if DVC is OOS or in
Digital Mode)Bit 2 - not usedBit 1 - Internal Sensor Out of Limits
(travel, pressure, ortemperature sensors reading beyond their
limits)Bit 0 - Variable Out of Range (Primary Variable loop
currentout of -25% to +125% range)Page 40HART Command 0 HART
Command 0HART Command 0 Hello, who are you? Used by a HART master
to match a newly found field device with its proper DD
file.(preamble, address stuff) 13 03 05 05 01 05 08 00 32 36 02
(checksum stuff) Manufacturer (i.e. code for Fisher Controls)
Device type (i.e. code for DVC6000) Number of preambles (always 5
for a FIELDVUE) Universal Revision (always 5 for a FIELDVUE) Device
Revision (DD version) Software Revision (PWB Firmware version)
Hardware Revision (encoded PWB Hardware version) Device function
flags (always $00 for a FIELDVUE) Device ID number (unique ID
number for each FIELDVUE) Page 41Right mouse clickon HART tagfor
context menuChoose Communications LogAvailable user tool:ValveLinks
Communication LogAvailable user tool:Available user
tool:ValveLinkValveLinkssCommunication LogCommunication LogPage
42Running log of HART commands sent between ValveLink and
DVCRunning log of HART commands Running log of HART commands sent
between ValveLink and DVCsent between ValveLink and
DVCNewest...OldestFull detailsof highlightedcommandCan be reviewed
or exported and saved as a file. Page 43HART CommunicationsHART
Communications--Communication ErrorsCommunication ErrorsPage 44HART
Communications errors HART Communications errorsHART Communications
errorsF1 F2 F3 F4DVC6000: HART TagDevice DisconnectedRETRY QUITF1
F2 F3 F4DVC6000: HART TagAccess RestrictedInstrument was takenOut
of Service byanother master.ABORTOKPage 45What happens when things
go wrong? What happens when things go wrong?What happens when
things go wrong?You can get HART Communication Errorswhen: Two
masters of the same gendertalk at the same time on one loop. A host
which doesnt arbitrate between multiple masters very well.
Electrical noise messes up the HART signal.Unfortunately, its hard
to tell these apart!Page 46Two masters of the same gendertalking at
the same timeTwo masters of the same Two masters of the same
gendergendertalking at the same timetalking at the same timeYou
manually have to separate them: Hosts with HART AO are ALWAYS
Primary master. 275 and 375 handheld HART Communicators are ALWAYS
Secondary Master. PC programs like AMS Device Manageror AMS
ValveLink VL2000 Soloor the Moore IndustriesHIMcan be either
master, so they are the candidates to be moved out of the way.
BUTthere can only be ONE of any gender.Page 47A host which doesnt
arbitrate between multiple masters very wellA host which doesnA
host which doesnt arbitrate t arbitrate between multiple masters
very wellbetween multiple masters very well Ouch! Most notable when
things that work OK separately do not work when connected together
with a host system. Usually the best solution is to limit HART
applications to just a single master (usually the host Primary
master).Page 48 Too much of a good thing Too much of a good thing
Too much of a good thing Each of the HART communication schemes
usually work OK by itself. Primary Master talking to a field device
Secondary Master talking to a field device Field device in Burst
Mode communicating to a Tri-Loop Problems may arise if two or more
of these schemes are applied together. HART traffic jamsoccur.
Often the only way to remedy them is to live with a fewer number of
simultaneous HART communication schemes.Page 49DemonstrationPage
50HART CommunicationsHART
Communications--MultiplexersMultiplexersPage 51HART communication
devices HART communication devicesHART communication devicesSeveral
ways to communicate HART with a single FIELDVUE Instrument:Page
52HART Multiplexers HART MultiplexersHART MultiplexersWhat is a
Multiplexer? A hardware means to have physical connectivity for
HART communications to many field devices. Contains one or more
HART modems that are shared sequentially among all connected field
devices. Communicates with a host computer via RS485 (addressable
serial data communication protocol) and communicates HART to all
the connected field devices.Page 53What is a multiplexer ? What is
a What is a multiplexermultiplexer??mul-ti-plex: being or relating
to a system of transmitting several messages simultaneously on the
same circuit of channelThink of it as a HART modem in a box with
lots of simultaneous electrical connections.The four brands of HART
multiplexers supported by AMS ValveLink Solo software: ARCOM
(Rosemount 2530H1 HART Interchange) P & F KFD2-HMM-16 series
ELCON 1700 and 2700 series MTL 4841 seriesPage 54RosemountType
2530H1 HART InterchangeRosemountRosemount Type 2530H1 Type 2530H1
HART InterchangeHART Interchange 32 channels per multiplexer Four
independent HART modems One HART modem for every 8 channels(1 8, 9
16, 17 24, 25 32) Up to 32 multiplexers per RS485 serial network No
backplane options requires an electrical tap into each monitored
loop (a HART filter in the loop works good for this
connection).Page 55Pepperl & FuchsKFD Series
PepperlPepperl& Fuchs& Fuchs KFD SeriesKFD Series One
master module, up to 15 slave modules, up to 256 channels per
multiplexer Up to 31 multiplexers per RS485 serial network One HART
modem shared among all 256 channels Various backplane
optionsKFD0-HMS-1616 channel slave moduleKFD2-HMM-1616 channel
master modulePage 56Pepperl & FuchsELCON HIS series
PepperlPepperl& Fuchs& Fuchs ELCON HIS seriesELCON HIS
series One master module with 32 channels Up to 32 multiplexers per
RS485 serial network One HART modem shared among all channels
Various backplane options, host FTA replacements Page 57MTL4840
series MTLMTL 4840 series4840 series One master module, up to 15
slave modules, up to 256 channels per multiplexer Up to 31
multiplexers per RS485 serial network One HART modem shared among
all channels Various backplane options Page 58Typical Multiplexer
Network Typical Multiplexer NetworkTypical Multiplexer
Network(MTL4840 shown)MultiplexerMultiplexerField Termination
AssemblyField Termination AssemblyRS485RS485Multi-address
serialAddresses: 1 319600 38,200 baudOne HART
modemsequentiallyserving 1 to manyfield devicesPage 59Network Alert
Scan Network Alert ScanNetwork Alert Scan An application of AMS
ValveLink Solo. Optimized to scan a defined population of FIELDVUE
instruments as quickly as possible. It is the enginewithin AMS
ValveLink Solo for Alert Scanning, Trending, and Modbus slave
functionality. Freshness of HART information from the scanned
population of FIELDVUE instruments is important.Page 60Network
Alert Scan Network Alert ScanNetwork Alert ScanPage 61Mechanics of
Network Alert Scan: Mechanics of Network Alert Scan:Mechanics of
Network Alert Scan: HART Command 3 is issued to each FIELDVUE
Instrument to gather its four primary variable values. If the More
Status Availablebit is active in the HART Command 3 reply,
ValveLink issues a HART Command 48 to gather the DVCs alert
information.Page 62So how fast can the Network Alert Scan scan?So
how fast can the Network Alert Scan So how fast can the Network
Alert Scan scanscan??Refresh Time is the time it takes AMS
ValveLink Solos Network Alert Scan to scan its entire population of
FIELDVUE devices and update its Alert Log.Refresh Time =
Multiplexer Refresh Time + Gathering TimeIt is a function of:
ValveLink Network Alert Scan default settings Number of FIELDVUE
Instruments in the scan list Number of FIELDVUE Instruments being
served by one HART modem RS485 serial communication rates between
ValveLink PCs COM port and multiplexers Any alert conditions
existing in the FIELDVUE instrumentsPage 63Settings in Customize
ValveLink Settings in Settings in Customize ValveLinkCustomize
ValveLinkChanges from default settings:Set to maximumSet to
minimumDe-select bothPage 64Multiplexer Refresh TimeMultiplexer
Refresh Time Multiplexer Refresh Time 205 sec 256 Up to 256 1KFD
SeriesP&F205 sec 256 Up to 256 14840 SeriesMTL7 sec 8 32 4
HARTInterchangeARCOM /Rosemount26 sec 32 32 1 1700/2700
ELCONRefresh Time (Max)Devices / Modem (Max)Channels Modems Model
Manufacturer/Supplier Multiplexer Refresh Time is a function of the
number of connected devices per multiplexer modem. This is
calculated as 0.8 seconds per device per modem. Page 65Gather Time
Gather TimeGather Time Gather Time is the rate AMS ValveLink Solo
extracts instrument data from the multiplexers. This rate depends
on the baud rate used by the PCs COM port to communicate over the
RS-485 link to the multiplexers. 50 38.4K25 19.2 K15
9600Instruments per second Baud RatePage 66Gather Time Gather
TimeGather TimeIf no alerts are present in the FIELDVUE
instruments, the time required to gather data is calculated
as:Gather Time (seconds) = (Number of Instruments / Instruments per
sec) + 1If alerts are present in the FIELDVUE instruments, the time
required to gather data is calculated as:Gather Time (seconds) =
(Number of Instruments / Instruments per sec) + 1 + (Number of
Instruments with active alerts)Page 67Example Refresh Time
calculation -Two quad-modem ARCOM multiplexers:Example Refresh Time
calculation Example Refresh Time calculation --Two quadTwo
quad--modem ARCOM multiplexers:modem ARCOM multiplexers: 50
FIELDVUE instruments are connected to a multiplexer network
consists of two ARCOM multiplexers. Each multiplexer has 25
instruments (7 on one modem, 6 on each of the other modems)
connected to it. Three FIELDVUE instruments have alerts present.
The multiplexer baud rate is 19.4K baud.Calculated Multiplexer
Refresh Time:7 * 0.8 = 5.6 secondsCalculated Data Gathering
Time:50/25 +1 + 3 = 6.0 secondsTotal AMS ValveLink Solo Refresh
Time = 11.6 secondsPage 68What does this mean? What does this
mean?What does this mean?Instead of second for one HART message:It
will take 11.6 seconds for one HART message!The rest of the time,
the HART modem isbusy talking to other FIELDVUE Instruments.Page
69Two single-modem multiplexers each with one slave module:Two
singleTwo single--modem multiplexers each modem multiplexers each
with one slave module:with one slave module: The same 50 FIELDVUE
instruments are connected to a multiplexer network consists of two
MTL or P&F multiplexers. Each multiplexer has a one slave
module added to the master module with 25 instruments connected per
mux. Three FIELDVUE instruments have alerts present. The
multiplexer baud rate is 19.4K baud.Calculated Multiplexer Refresh
Time:25 * 0.8 = 20.0 secondsCalculated Data Gathering Time:50/25 +1
+ 3 = 6.0 secondsTotal AMS ValveLink Solo Refresh Time = 26.0
secondsPage 70 The same 50 FIELDVUE instruments are connected to a
multiplexer network consists of one MTL or P&F multiplexer
consisting of the master module and three slave modules. Three
FIELDVUE instruments have alerts present. The multiplexer baud rate
is 19.4K baud.Calculated Multiplexer Refresh Time:50 * 0.8 = 40.0
secondsCalculated Data Gathering Time:50/25 +1 + 3 = 6.0
secondsTotal AMS ValveLink Solo Refresh Time = 46.0 secondsOne
single-modem multiplexer with three slave modules:One singleOne
single--modem multiplexer modem multiplexer with three slave
modules:with three slave modules:Page 71 The same 50 FIELDVUE
instruments are connected to a multiplexer network consists of four
MTL or P&F multiplexers consisting of only the master modules
and no slave modules. The devices are unevenly distributed (16 + 16
+ 16 + 2) Three FIELDVUE instruments have alerts present. The
multiplexer baud rate is 19.4K baud.Calculated Multiplexer Refresh
Time:16 * 0.8 = 12.8 secondsCalculated Data Gathering Time:50/25 +1
+ 3 = 6.0 secondsTotal AMS ValveLink Solo Refresh Time = 18.8
secondsFour single-modem multiplexers with no slave modules:Four
singleFour single--modem multiplexers modem multiplexers with no
slave modules:with no slave modules:Page 72 The same 50 FIELDVUE
instruments are connected to a multiplexer network consists of four
MTL or P&F multiplexers consisting of only the master modules
and no slave modules. The devices are more evenly distributed (13 +
13 + 12 + 12) Three FIELDVUE instruments have alerts present. The
multiplexer baud rate is 19.4K baud.Calculated Multiplexer Refresh
Time: 13 * 0.8 = 10.4 secondsCalculated Data Gathering Time:50/25
+1 + 3 = 6.0 secondsTotal AMS ValveLink Solo Refresh Time = 16.4
secondsFour single-modem multiplexers with no slave modules:Four
singleFour single--modem multiplexers modem multiplexers with no
slave modules:with no slave modules:Page 73Summary of Refresh Times
with the various mux arrangements:Summary of Refresh Times with the
Summary of Refresh Times with the various mux arrangements:various
mux arrangements: Two quad-modem ARCOM multiplexers: 11.6 seconds
Two single-modem multiplexers with one slave module each: 26.0
seconds One single-modem multiplexer with three slave modules: 46.0
seconds Four single-modem multiplexers with no slave modules
(unbalanced load): 18.8 seconds Four single-modem multiplexers with
no slave modules (evenly balanced load): 16.4 secondsData
acquisition speed from a HART Multiplexer Network depends mainly
upon the number of HART modems.Page 74What if the RS485 baud rate =
9600? What if the RS485 baud rate = 9600?What if the RS485 baud
rate = 9600?Calculated Data Gathering Time:50/15 +1 + 3 = 7.3
seconds Two quad-modem ARCOM multiplexers: 11.6 seconds 12.9
seconds Two single-modem multiplexers with one slave module each:
26.0 seconds 27.3 seconds One single-modem multiplexer with three
slave modules: 46.0 seconds 47.3 seconds Four single-modem
multiplexers with no slave modules (unbalanced load): 18.8 seconds
20.1 seconds Four single-modem multiplexers with no slave modules
(evenly balanced load): 16.4 seconds 17.7 secondsPage 75Multiplexer
summary: Multiplexer summary:Multiplexer summary: Handy way to
electrically connect numerous FIELDVUE Instruments to the PC
software. Pay the price with HART scanning speed. The fastest
scanning will be with the least number of devices per HART modem.
Increasing RS485 baud rate helps, but not by much compared to HART
modems. Load Balancing so that similar number of devices are on
each modem optimizes the scanning speed.Page 76Data from a FIELDVUE
Instrument via HARTData from a FIELDVUE Instrument Data from a
FIELDVUE Instrument via HARTvia HART General device identification
information HART tag, Manufacturer, Type, Serial number, etc.
Parametric values 4 primary and several non-primary variables IEEE
floating point format URV, LRV, and units code Device Status byte
Available with every reply message Status Integrity bytes Available
in response to a HART Command 48Page 77Network Alert Scan Network
Alert ScanNetwork Alert Scan 16 DVC6000s 4 DVC6000s with active
alerts Single modem multiplexer Communicating with ValveLink Solo
at 38,400 baud Performing ValveLinks Network Alert Scan Refresh
Time = = (16*0.8) + [(16/50) + 1 + 4]= (12.8) + (5.3) = 18.1
seconds Network Alert Scan gets update from every DVC6000 every 18
seconds.HART Modem#1#3#5#7#9#11#13#15#12#10#14#16#2#4#6#8Page
78What happens when a FIELDVUE Instrument experiences an
intermittent fault?Is it detected by the Network Alert Scan?Page
79If a fault occurs and clears between messages?No indication!If a
fault occurs during a HARTcommunication message? The active alert
is indicated.HART sampling and communication of intermittent device
faultsHART sampling and communication HART sampling and
communication of intermittent device faultsof intermittent device
faultsXXXXXX XXXIf a fault occurs when you are not communicating
via HART?No indication!Hint:Enable the FIELDVUEs Alert Recordto
capture these intermittent events. Page 80The DVCs Alert Record The
DVCThe DVCs Alert Records Alert Record Like mailboxes, each record
entry holds the alerts captured during one event. DVC5000 has 1
entry DVC6000 has 11 entries DVC2000 has 20 entries Events are
captured at each cpu processing cycle. When at least one entry is
populated, the Alert Record not Emptystatus is set. When all
entries are populated, the Alert Record Fullstatus is set.Page
81Network Alert Scan can watch for the DVC Alert Record Network
Alert Scan can watch for Network Alert Scan can watch for the DVC
Alert Record the DVC Alert Record Scanning the device with Network
Alert Scanwill pick up Alert Record Not Empty, even if thecaptured
intermittent event failure has cleared.Page 82HART
CommunicationsHART Communications--SummarySummaryPage 83What is
HART communication? What is What is
HARTHARTcommunication?communication? Superimposed 1200 baud digital
communication signal on the Analog Control signal using the Bell
202 Frequency Shift Keying (FSK) standard. For a digital valve
controller on an AO channel, the HART waveform is modulation of the
loop voltage.TerminalVoltage2200 Hz1200 Hz"1" "0"+0.5 VDC- 0.5
VDCPage 84HART is: HART is:HART is: Question - Answerprotocol
Primary / Secondary masters Burst Mode Communications Extremely
politearbitration between mastersPrimary SecondaryPage 85What is a
HART Filter ? What is a What is a HART FilterHART Filter??Acts like
a wallto block HART signals from AO cards that would attenuate the
HART waveform.Page 86What is a multiplexer? What is a
multiplexer?What is a multiplexer?Think of it as a HART modem in a
box with lots of simultaneous electrical connections. ARCOM
(Rosemount 2530H1 HART Interchange) P & F KFD2-HMM-16 series
ELCON 1700 and 2700 series MTL 4841 seriesHART
Modem#1#3#5#7#9#11#13#15#12#10#14#16#2#4#6#8Page 87Typical
Multiplexer Network Typical Multiplexer NetworkTypical Multiplexer
NetworkMultiplexerMultiplexerField Termination AssemblyField
Termination AssemblyRS485RS485Multi-address serialAddresses: 1
319600 38,200 baudOne HART modemsequentiallyserving 1 to manyfield
devicesPage 88Troubleshooting tools: Troubleshooting
tools:Troubleshooting tools:Network Alert ScanCommunication LogHART
Audio MonitorPage 89Where to go for more information? Where to go
for more information?Where to go for more information? DVC6000
Series FIELDVUEDigital Valve ControllerInstruction Manual, Form
5647 FIELDVUEHF300 Series HARTFiltersInstruction Manual, Form 5715
Audio Monitor for HARTCommunicationsInstruction Manual Supplement,
Form 5811 HARTField Communication ProtocolInstruction Manual
Supplement, Form 5812 Using the HARTTri-LoopHART-to-Analog Signal
Converter with FIELDVUEDigital Valve ControllersInstruction Manual
Supplement, Form 5813 FIELDVUE Product website: www.FIELDVUE.com
HART Communication Foundation website: www.hartcomm2.org MTL
Instruments website: www.mtl-inst.com Pepperl & Fuchs (P &
F, ELCON) website: www.pepperl-fuchs.com ARCOM website:
www.arcom.comPage 90Thank you for attending!! Thank you for
attending!!Thank you for attending!!Questions?