The document discusses the HART (Highway Addressable Remote Transducer) communication protocol, highlighting its benefits such as cost savings, improved operational flexibility, and compatibility with existing analog systems. It covers specifications, modes of communication, command groups, and the integration of Wireless HART technology, facilitating modern process automation needs. The document also explores various industrial applications and emphasizes the protocol's ability to enhance efficiency in areas like inventory management, cost reduction, and safety in hazardous environments.

1. HART
highway addressable remote transducer
Ravikumar Koturwar 13MAC0038
Rahul S Kore 13MAC0041
Parth M Mehta 13MAC0048

2. VIT UNIVERSITY, SELECT 1

3. Why its Popular now
The HART protocol directly contributes to these
business goals by providing cost savings in:
Commissioning and installation
Plant operations and improved quality
Maintenance
Analog 4–20 mA and digital signals provide
flexibility not available with any other
communication technology.
Hand Held Communicators are often used to
perform device set-up, calibration, commissioning
and periodic maintenance
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4. Improved plant operations
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5. Operational Flexibility
 Multi-master Operation?
 Primary master ---- control system
 Secondary master ---- A hand-held communicator or a maintenance
computer.
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6. Instrumentation investment protection
 Wiring, analog controllers, barriers, analog or smart
instrumentation
exists widely
 The HART communication protocol enables you to retain your
previous investments in existing hardware and personnel.
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7. Digital communication
 The HART protocol enhances the capabilities of digital
instruments by providing communication access and
networking
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8. HART Vs. Fieldbus
HART is compatible with existing wiring in older
plants.
Hart is understood, accepted and appreciated by
virtually everyone involved.
Fieldbus costs a lot more to implement, especially for
existing equipment.
Lot of instruments not radially available with
Fieldbus.
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9. HART specifications?
 Physical form of transmission
 Transaction Procedures
 Message structures
 Data formats
 Set of commands to perform required operation.
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10. Communication Modes of HART?
Master Slave Mode (Poll---Response Mode)
Maximum communication speed --- 2 messages/sec.
Configuration ---- Point-to-point or Multi-point
Master sends command (request) , slave responds (replies)
Request
Reply
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11. Burst Mode ( Broadcast Mode)
Slave transmits messages continuously (e.g. values of a measurand).
The communication speed --- 3 message/sec.
A slave device repeatedly sends a data message.
Used for fast updation of the value of a measured variable
Continuous Reply
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12. HART Signal Levels?
 HART protocol specifies that master device transmit a voltage signal
whereas slave device transmits a current signal.
 The current signal is converted in to corresponding voltage by a loop load
resistor(250 ohms), so all devices use voltage sensitive receiver circuits.
 The wave shape is sinusoidal, but trapezoidal waveform is acceptable. A
square wave is not acceptable.
Master Slave Operation?
 The each message transaction is originated by the master station, the slave
device only replies only when it receives a command message.
 The reply from the slave device acknowledges that the command has been
received and may contain data requested by the master.
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13. Different HART networks?
Point-to-point Mode
 Both analog and digital communications are supported.
 4–20 mA signal is used to communicate one process variable.
 Additional process variables, configuration parameters, and other device
data are
transferred digitally using the HART protocol
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14. VIT UNIVERSITY, SELECT 13

15. Multidrop Mode
 Only digital communication is supported
 Requires only a single pair of wires
 In case safety barriers and an auxiliary power supply for up to 15 field
devices
 All field device polling addresses are >0, and the current through each
device is fixed to a minimum value (typically 4 mA).
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16. 15

17. Different Groups of HART commands?
 Universal : Provides functions which are implemented in all field devices.
Examples : Read model
Read serial number
Read range
 Common Practice : Provides functions common to many field devices but
not all. If a device uses these functions, these commands should be used
to perform them.
Examples : Read (up to 4) variables
Perform calibration check
Perform self-test
 Device specific : Provides functions which are more or less unique to a
particular filed device .
Examples : Select 0C/0F (temperature sensor)
Tune a control parameter (control device)
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18. Command Summary
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19. Types of Frame Formats in HART protocol?
 Short frame format ---- Older HART instruments(Version4) used short
frame format. In this the address of the slave device is ‘o’.
 Long frame format ---- HART version 5 introduced ‘Long frame format”. In
this the address of the slave device is world wide unique identifier.
It is a 38 bit number derived from the manufacturer code.
It contains the device code and device id no
Long frame format gives extra security against the possible reception and
acceptance of command meant for another device, either due to external
interference or due to excessive cross talk
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20. Some More Points
 pass-through feature?
 DD?
 Interoperability?
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21. Wireless HART
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22. Introduction
 Wireless HART is a wireless mesh network communication protocol.
 It is designed to meet the needs for process automation applications
 It is a KEY part of the HART field communication protocol Version 7
 Less than 10% of the installed HART instruments have a direct
communications link back to a host system.
 The addition of low-cost wireless connectivity provides a pathway for
remote host systems to read process and maintenance information from
field instruments, both old and new.
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23. Wireless HART Network Structure
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24. Wireless Mesh
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25. Time Synchronization
Report by Exception – Time- and Condition-based Alerts
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26. Time Stamp
 synchronized clock enabling it to transmit data at the correct
time.
 Used to stamp time and date
Wireless Co-existence
 Uses channel assessment and short message sizes to coexist
with neighboring networks
Wireless Diagnostics
 Ensures the health of the network
Include indicators of battery life remaining, devices present,VIT UNIVERSITY, SELECT 25

27. Wireless Security
 Join Key
 Unique Message Integrity Code (MIC)
 Message Encryption
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28. Loop Testing
 No 4 to 20 mA signal
 It checks that the process data is displayed correctly at the
host and also tests other control functions.
Wireless HART Adapter
 New HART device can be added to wired device to provides
wireless Feature
 Loop - Powered
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29. WIRELESS NETWORK
28

30. PART 2
FSK
HART signal
HART protocol
MUX
Comparison
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31. CHARACTERISTICS
Simultaneously supports two communications channels.
» 4-20mA "analog" communications and
» Modulated two-way "digital" communications.
Additional process data in Multi-Variable devices used to
improve plant operation
Field devices can continuously publish their process data.
» Operators alerted to impending problems before
negative impact to the process = Real time device
diagnostics.
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32. FSK
Bell 202 Frequency Shift Keying (FSK) standard
to superimpose digital communication signals at a low level
on top of the 4-20mA.
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33. HART SIGNAL
in Physical layer
HART allows additional information to be carried on the same pair of
wires with the 4-20 mAAnalog Signal
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34. TWO COMMUNICATION CHANNEL
4-20mA "Analog" Channel
HART"Digital"Channel
 4-20mAAnalog support large part
of Protocol Specifications
 One-way communication of one
process value
 Simple Low Pass Filter isolates 4-
20mA signal
Compliments 4-20mA
Based on Analog Telephone Modems
» Long Cable Runs
» High Noise Immunity
» You can "hear" HART
 Two-way Communications
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35. Example
Fig : Two Communication Channels
• Connecting a PC to a HART device or network
• PC application development tools > PC configuration software
• Universal handheld communicator >275 Universal
• Reading HART data into non-HART systems
• Commissioning HART networks > HART multidrop networks
• Control system interfaces > Control in field devices
• Multiplexers
• Device status and diagnostics
• Intrinsic safety(IS)
The following sections contain information that can help you to get the most from your HART
system:
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36. CABLE LENGTH
TABLE: Allowable cable lengths for(#18 AWG) shield twisted pair
Theoretical Length max. :
Affected by: electrical characteristics ( mostly Capacitance)
& Combination of connected devices
 It is also a good idea to buy a cable designed for HART.
 Belden 3105A is an example of such a cable.
3,000 meter (10,000 ft)
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37. HART PROTOCOL
LAYERS
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38. • Controlled by HCF
• Open and Available to Anyone
• Easy-to-Read Language
• Consistent and well-defined terms
Organization of HART
Specifications
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39. Protocol Structure
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40. LONG FRAME FORMAT
39

41. Packet Structure
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42. RESPONSE
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43. General device status is always returned with
COMMAND3
HART COMMAND 3
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44. STATUS MESSAGES ARE:
Status Messages
 Field device malfunction (Bit 7)
 Configuration changed (Bit 6)
 Cold start (Bit 5)
 More status available (Bit 4)
 Analog output current fixed (Bit 3)
 Analog output saturated (Bit 2)
 Non-primary variable out of limits (Bit 1)
 Primary variable out of limits (Bit 0)
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45. COMMAND 48
Device specific information is always returned with COMMAND48
25 bytes of additional status information
*Not necessary to use all the bytes Ex. Honeywell STT250 uses only
first 3 bytes.
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46. VIT UNIVERSITY, SELECT 45

47. MultiplexersTo interface numerous
HART devices
Support point-to-point
and all-digital (multidrop)
Communication between a multiplexer and
host depends on the multiplexer capabilities
RS232C, RS485, Modbus, TCP/IP Ethernet
can be used as primary I/O front end for a
HART-based control or monitoring system
When installing HART multiplexer systems, the following capabilities should be
considered:
o Number of HART channels supported
o Number of HART channels that share a HART modem
o Burst mode support
o Multidrop support
o Method of communication with the host computer or control system
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48. 1. PARALLEL MONITORING WITH A
MULTIPLEXER
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49. PC acts as the host, providing the human-machine interface & perform high-
level functions.
Mux passes HART commands from the host computer to the field devices.
continuously monitors the field devices, reports the current readings and
instrument status to the host,
Figure: HART Multiplexer as the Primary I/O System
2. MULTIPLEXER AS THE PRIMARY I/O SYSTEM
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50. Multiplexer refresh time > function of no. of devices
connected per channel
Refresh time = 0.8sec / device / modem
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51. 3. CONTROL FIELD DEVICES
Figure: Transmitter with PID (HART Slave)
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52. Wireless HART
vs. Bluetooth
vs. Zigbee
Range
Data security = Reliable message delivery
Industrial grade robustness = Industry acceptance
Reliability.
*No HART device use Bluetooth connectivity with data load.
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53.  No frequency diversity > Entire network shares same static channel
 Static Channel also susceptible to interference with wireless LAN
 Makes it susceptible to both intended and unintended jamming
 Can stop entire network communication
 Designed from start for robust and secure Communication
 Network works 24*7 > no option to turn it completely off
 Mesh networking with graph routing > provide redundancy and self healing
ZigBee
Wireless HART
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54. Comparison at layer level
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55. Versions
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56. Industry App’s
PART 3
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57. VIT UNIVERSITY, SELECT 56

58. Reading HART Data into
Non-HART Systems
Many HART products are able to perform more than one
measurement or
output function (e.g., make multiple process measurements,
calculate
process information, and provide positioner feedback
information). All of
this information can be easily accessed digitally. However, existing
controllers or interface equipment may not have the ability to read
digital
HART data. Products are available that can read HART digital
signals and
convert them to analog or contact information, which enables any
traditional analog/digital I/O to take full advantage of the benefits of
HART-communicating devices.
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59. The Tri-Loop module monitors a HART loop for a bursting message and
converts three of the four possible variables in HART communicator.
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60. The site programmable alarm
( SPA )module continuously communicates with any HART-capable
device and provides contact closure outputs (alarm trips) based on the
information received (Figure 14). For example, the SPA can be
configured to monitor the device-status information inherent in the
HART communication protocol and trigger events such as local on/off
applications or alarms. The SPA can also initiate emergency shutdown
action if problems are detected with a field device in critical loop
applications
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61. Industrial Application
Many companies in a wide variety of industries have already
realized the advantages of using the HART communication
protocol. This section describes some applications in detail and
outlines the tangible benefits that result.
The applications have been grouped into the following sections:
Inventory-management applications
Cost-saving applications
Remote-operation applications
Open-architecture applications
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62. Inventory-Management
Applications
Accurate measurements for inventory management are essential
in all industries. The HART communication protocol enables
companies to make sure inventory management is as efficient,
accurate, and low cost as possible.
Tank level and inventory management is an ideal application for a
HART multidrop network . The HART network digital update rate
of two PVs per second is sufficient for many tank-level
applications. A multidrop network provides significant installation
savings by reducing the amount of wiring from the field to the
control room as well as the number of I/O channels required.
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63. VIT UNIVERSITY, SELECT 62

64. VIT UNIVERSITY, SELECT 63

65. UNDERGROUND PETROLEUM
STORAGE WITH HART
COMMUNICATION FOR
ACCURACY
Underground salt caverns are frequently used for crude oil
storage. One customer pumps oil from barges into the
storage caverns. An ultrasonic flow-meter records the
total flow. To get the oil out of the caverns, a brine
solution is pumped into the cavern through a magnetic
flow-meter. Brine and crude oil flowing in both directions
are measured and reported to the DCS using the HART
communication protocol for accuracy.
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66. VIT UNIVERSITY, SELECT 65

67. Cost-saving applications
A Texas wastewater treatment plant replaced stand-alone
flow meters and chart recorder outstations that required
daily visits for totalization with a HART system. HART-
based magnetic flow meters were multidropped into
HART RTUs to create a cost-effective SCADA
network. The use of HART technology reduced system
and cable costs, enhanced measurement accuracy, and
eliminated time-consuming analog calibration
procedures
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68. A consumer appliance manufacturer used the networking
capability of the HART protocol to ensure level, flow, and
pressure HART multidrop provided substantial wiring
and installation savings as well as digital accuracy with
the elimination of the analog to digital (A/D) and digital to
analog (D/A) conversions of the instrument and PLC I/O.
Figure shows pressure transmitters connected to a PLC via
smart transmitter interface multiplexers.
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69. VIT UNIVERSITY, SELECT 68

70. Remote-Operation
Applications
Choosing the HART communication protocol for all-digital communication
in a wide-area network enabled one company to have real-time
monitoring
and control, access to diagnostics, and maintenance capabilities—all
from a
remote location.
Each platform’s RTU provided a link to approximately 50
temperature,
pressure, and flow transmitters. The RTU used the multi-master
capability of the HART protocol to enable the second RTU to act as a hot
standby, which monitored activity and was able to take over if a failure
occurred. The RTUs provided links with the emergency and safety
systems
and a local interface for maintenance personnel. The Modbus protocol
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71. VIT UNIVERSITY, SELECT 70

72. In a Venezuela gas-lift project, HART multidrop
technology was used for remote operation of offshore
gas-lift production wells at considerable savings:
30% decrease in installation costs
16:1 reduction of input modules
Reduced cost of I/O cards in the RTU
Remote re-ranging
Remote access to the transmitter status for improved
process uptime
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73. Open-Architecture
Applications
The best way to judge the openness of a communication protocol
is by the
number of products supported. By this standard, the HART protocol
is
perhaps the most open of any field-communication protocol available
today.
In a major refinery expansion, an oil company weighed the advantages
of
using either a proprietary system or a HART-based system. The results
indicated that the company could use HART digital instruments in 92%
of
their applications, compared to only 33% with the proprietary system.
Choosing HART products resulted in an incremental $23,000 in
savings
due to commissioning efficiencies and ongoing maintenance andVIT UNIVERSITY, SELECT 72

74. VIT UNIVERSITY, SELECT 73

75. VIT UNIVERSITY, SELECT 74

76. Intrinsic Safety
Intrinsic safety (IS) is a method of providing safe operation of electronic
process-control instrumentation in hazardous areas. IS systems keep the
available electrical energy in the system low enough that ignition of the
hazardous atmosphere cannot occur. No single field device or wiring is
intrinsically safe by itself (except for battery-operated, self-contained
devices), but is intrinsically safe only when employed in a properly
designed IS system.
HART-communicating devices work well in applications that require IS
operation. IS devices (e.g., barriers) are often used with traditional
two-wire 4–20 mA instruments to ensure an IS system in hazardous areas.
With traditional analog instrumentation, energy to the field can be limited
with or without a ground connection by installing one of the following IS
devices
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77. Shunt-diode (Zener) barriers that use a high-quality safety ground
connection to bypass excess energy
Isolators, which do not require a ground connection, that repeat the
analog measurement signal across an isolated interface in the safe-side
load circuit Both Zener barriers and isolators
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78. VIT UNIVERSITY, SELECT 77

79. When designing an IS loop using shunt-diode barriers, two
additional
requirements must be considered:
1. The power supply must be reduced by an additional
0.7 V to allow
headroom for the HART communication signal and yet not
approach
the Zener barrier conduction voltage.
2. The load resistor must be at least 230 Ω (typically 250 Ω).
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80. HART is a backward compatible enhancement to 4-
20mA instrumentation that allows two way
communication with smart, microprocessor-based
field devices.
Continuously Validate Integrity of Control Information
–Ensure accuracy of system data/ Automatically
detect any deviation between device and system
Continuous Real Time Diagnostics
– Device Problems/ Loop Current Faults
– Device Needs Maintenance
Unlock additional information in Multi-Variable
devices
CONCLUDE
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81. Wireless HART is designed based on a set of funda-
mental requirements: it must be simple (e.g., easy to
use and deploy)
Self-organizing and self-healing.
flexible (e.g., support different applications)
Scalable (i.e., fit both small and large plants)
Reliable, secure, and support existing HART
technology (e.g., HART commands, configuration
tools, etc.)
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82. VIT UNIVERSITY, SELECT 81

83. Questions??
Ravikumar Koturwar 13MAC0038
Rahul S Kore 13MAC0041
Parth M Mehta 13MAC0048
HART