Firstly, What is HART?
Highway Addressable Remote Transducer, known as HART, is a communication protocol that allows users to communicate with smart devices. This is achieved by using analog wiring to communicate directly with a smart device i.e. a Burns Engineering T55 Temperature Transmitter.
This standard has been implemented since the mid-1980s and is the most popular communication protocol used today.
This standard has been implemented since the mid-1980s and is the most popular communication protocol used today.
Burns Engineering T55 Temperature Transmitter
Before HART was established, older devices traditionally had to be adjusted and set up by either:
- Adjusting the span and range screws at the device.
- Removing the casing of the device and changing out the range jumpers on the PCB.
Yokogawa EJA110E Differential Pressure Transmitter with HART
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Establishing the type of work and determining
what you need to achieve it
Establishing the type of work and determining
what you need to achieve it
This is probably the most important aspect to consider when using or choosing the right HART communication device for your application.
With the various amounts of HART communicators available, it sometimes can be difficult to choose the correct job for the tool. For example, if a calibration technician would like to perform a pressure calibration on a transmitter, wouldn’t it be much more beneficial to have a pressure calibrator with built-in HART comms, rather than a separate communicator and calibrator?
Considerations like this will save you time and money.
Some worthwhile questions to ask yourself when choosing a viable HART communicator may be:
With the various amounts of HART communicators available, it sometimes can be difficult to choose the correct job for the tool. For example, if a calibration technician would like to perform a pressure calibration on a transmitter, wouldn’t it be much more beneficial to have a pressure calibrator with built-in HART comms, rather than a separate communicator and calibrator?
Considerations like this will save you time and money.
Some worthwhile questions to ask yourself when choosing a viable HART communicator may be:
- Is my HART communicator flexible and can I do other tasks with it?
- Is it user friendly?
- Do I have good technical support that I can trust and rely on?
- Is there more communication protocols available like ISA100, Profibus etc.?
Fluke 729 - Automatic Pressure Calibrator with built in HART Comms.
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Don’t forget your 250 OHM Resistor!
Don’t forget your 250 OHM Resistor!
This tip is definitely worth paying attention to! Speaking from experience there is nothing worse than preparing to do a calibration on a smart device and then suddenly realizing that there is no 250Ω resistor in the loop.
You would be correct to think that not all communicators require a 250Ω resistor within the loop but that is not always the case. If you can, always have a couple of 250Ω resistors in your pocket just in case!
You would be correct to think that not all communicators require a 250Ω resistor within the loop but that is not always the case. If you can, always have a couple of 250Ω resistors in your pocket just in case!
Why is it 250Ω resistor?
HART Communication technology has a very low power requirement (less than 3.8mA).
HART utilizes a frequency shift keying (FSK) modem to communicate over the primary variable analog signal wires.
By imposing the digital signal on top of the 4-20mA analog loop, HART allows for a simultaneous analog signal with a continuous digital communication signal that has no effect on the analog signal.
A minimum resistance of 230Ω is required to create an impedance with in the loop to allow for HART communication, so typically a 250Ω resistor is recommended as its easily available.
HART utilizes a frequency shift keying (FSK) modem to communicate over the primary variable analog signal wires.
By imposing the digital signal on top of the 4-20mA analog loop, HART allows for a simultaneous analog signal with a continuous digital communication signal that has no effect on the analog signal.
A minimum resistance of 230Ω is required to create an impedance with in the loop to allow for HART communication, so typically a 250Ω resistor is recommended as its easily available.
IPP’s Recommendation:
A Recommendation for a HART communication tool that is both reliable and cost conscious is Yokogawa’s Field Device management tool: FieldMate.
FieldMate is a PC based configuration tool that performs numerous tasks, including:
FieldMate is a PC based configuration tool that performs numerous tasks, including:
- initial setup,
- daily maintenance,
- troubleshooting,
- configuration backup for device replacement.
FieldMate supports the following communication protocols:
o BRAIN
o FOUNDATION™ fieldbus H1
o HART
o PROFIBUS
o ISA100.11a
o Modbus
Its user friendly design allows users to complete more complex tasks with confidence and ease. For example, with the ISA100 communication function, users can easily configure and provision wireless instruments in a matter of minutes which cuts down on installation and commissioning times greatly!
o FOUNDATION™ fieldbus H1
o HART
o PROFIBUS
o ISA100.11a
o Modbus
Its user friendly design allows users to complete more complex tasks with confidence and ease. For example, with the ISA100 communication function, users can easily configure and provision wireless instruments in a matter of minutes which cuts down on installation and commissioning times greatly!
 Alan Murphy | If you would like to find out more about what IPP can offer in terms of HART communicators, please do not hesitate to contact one of our in house product specialists. |  Ryan Fahey |
With over 30 years’ experience and multiple brands that you can trust, IPP will be able to offer guidance and support with any of your queries.
https://www.irishpowerandprocess.com/contact.html
https://www.irishpowerandprocess.com/contact.html
HART communicators, what's important to you?
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