HART 7 is a major enhancement to the HART® Protocol with many new features that enhance communication with HART-enabled devices. Perhaps the most significant of these new features is the new capability for wireless communication enabled by WirelessHARTTM.

The WirelessHART technology described in the HART 7.0 Specifications defines an interoperable standard for wireless communication in process measurement and control applications. This new capability combines the Power of HART with established and proven industry standards and technologies for wireless communication.

WirelessHART opens the door to new applications and opportunities for economic gain for both HCF members and industry users. This new technology leverages the capability of HART-enabled field device and host system products to be full participants in the wireless network and expands the reach of HART Communication into plant areas and applications that were not possible before.

The user experience and the guiding principle of backward compatibility is preserved. WirelessHART-enabled devices use the same HART command structure and work with the same software applications and tools as their 4-20mA based counterparts.

Following is a summary of key enhancements in the HART 7.0 Specifications.

Wireless
A major new enhancement to the HART technology providing additional capabilities to monitor the performance of plant assets in areas that were uneconomical or technically difficult with wired systems. This new enabling technology provides reliable, robust and secure wireless communication using standard IEEE 802.15.4 radios at 2.4 GHz for global application with Channel Hopping, Mesh Networking and robust Security appropriate for process applications. Five new specifications and improvements to several existing specifications describe the WirelessHART technology and the requirements for devices, adapters, gateways and network managers. The WirelessHART User Guide provides a good overview of the technology and should be read first before the specifications. The User Guide is not a specification and consequently, does not appear on the ballot.

New Wireless Documents

• WirelessHART User Guide – HCF_LIT-086
• Wireless Physical Layer Specification – HCF_SPEC-065
• TDMA Data-Link Layer Specification – HCF_SPEC-075
• Network Management Specification – HCF_SPEC-085
• Wireless Command Specification – HCF_SPEC-155
• Wireless Devices Specification – HCF_SPEC-290

Expanded Manufacturer Codes
Widespread growth and adoption of the HART Protocol has resulted in the available code space for 8-bit Manufacturer ID Codes being exhausted. Resolution requires the expansion of Manufacturer ID Codes from 8-bits to 16-bits. Previous addendums to the Data Link Layer Specification, Command Summary Specification and Universal Command Specification that are proven and already in use have been incorporated into this revision of the HART Protocol Specifications.

Time Stamped Data
New Data Type (Time) for Time Stamping of Device Variable Values in Universal Command 9 response. This new capability enables the Time Stamping of process variable values at the Field Device and their reporting to host applications via Command 9 with the Time Stamp or time interval from the previous value. Also, Common Practice Commands to set the device time of day have been added.

Enhanced Burst Mode
Burst mode communication has been enhanced to allow the bursting of more than one HART message and the ability to specify time interval or frequency for how often the message is to be sent (burst frequency). A form of event reporting is also defined enabling devices to automatically send message noting a change in Command 48 status or a change to the Configuration Change Counter.

Upgrade of Command 38 & 48 to Mandatory
These Common Practice Commands for Device Specific Status and reset of the Configuration Change Flag are upgraded to “Universal” status with HART 7.

Enhanced Sub Device & I/O System Commands
New Common Practice Commands have been defined to support the set-up and operation of Wireless Adapters and I/O Systems.

Read Trend Command
New Common Practice Command to read multiple values (or the trend) for a specified Device Variable.

Aggregated Read Command
New Common Practice Command to support expedited upload of Device Configuration enabling more than one command response to be read at a time.

Common Tables Additions
New Common Tables Additions to support Wireless and all other enhanced functionality.

Discrete Applications
This new Specification establishes the framework for defining the application of HART Communication to devices for point detection or discrete on/off type functionality.

ORDER HART 7 SPECIFICATIONS