- Using HART
- How to Choose HART Products
- Device Commissioning
- Configuration
- Integration
- Calibration
- Wire Length & Capacitance
How to Choose HART Products
When it comes to picking a HART product, buyers need to know what kind of questions to ask in order to pick a product that would suit their needs the best.. It might seem as if every vendor offers similar type of products, however the HART capabilities in instruments and systems may vary widely from vendor to vendor. Consequently, question vendors carefully. Below are some things to ask.
Most importantly, when specifying HART technology, be sure to require that:
- Devices are registered at the HART Communication Foundation
- Device Descriptions (DD) are registered at the Foundation
- Suppliers are Members of the HART Communication Foundation
This approach makes sure that devices or systems are fully HART compliant. It also ensures they have been tested and registered with the foundation. That way you are assured of:
- Interoperability with other HART-enabled devices and systems
- Getting a device that will provide the powerful features of HART technology
- Specifying a product that will fully integrate into your HART-enabled applications
For a list of registered devices, visit the Product Catalog or contact your device or control system supplier.
This mark insures you are getting a registered HART device.
Also, consider asking device suppliers the following:
- What variables does your device measure? -
- They may have a temperature transmitter that can measure two temperatures, plus calculated averages, etc. - What version of HART Protocol is supported?
- It is important that the device and the host have matching protocol versions. - What maintenance information is available? i.e., Does the device have more than basic monitoring capability, such as a valve sticktion measurement?
- What unique or special features (i.e. Wireless access, local HART indicator, etc.) does your device support?
Possible questions for I/O suppliers include:
- Is remote HART access built into the controller or does it require a stand-alone application like a multiplexer?
- Is the HART I/O refresh rate suitable for control applications? i.e. Some I/O built around a multiplexer is much slower than can be read by individual modems per channel.
- Can you apply tags to HART multivariable data? i.e. Which would allow you to use them in a control strategy.
- What features do you have to simplify calibration? i.e. Being able to set a zero trim?
- Does the I/O support multi-drop? i.e. Can you place multiple transmitters on a single wire into one I/O input channel?
Possible questions for control system suppliers include:
- Does your host use a “native” DD or does it require a different file type? i.e. Some systems offer alternative file types like DTM, IDTM or proprietary protocols.
- Is support for the full range of HART capabilities built into the system? i.e. Calibration support, maintenance condition monitoring, device specific configuration and graphical user interface.
- Does the HART information land in the controller, or does it just pass through? i.e. Do you need the HART information for control strategies?
- Does the system support asset conditioning monitoring? i.e. Device status change or configuration change.
- How is additional HART information presented to support teams? i.e. Is it by alarm banner, or sent via pager, email, audible tones, etc.
- How do you perform tests when there is an error in the device? i.e. using asset management applications in the device description.
For advice on what to do after products have been chosen, see device commissioning, configuration and calibration on the menu to the left.