Appendix c- additional hart protocol information, Introduction, Appendix c – Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules User Manual
Page 193: Additional hart protocol information, For det, Appendix
Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
193
Appendix
C
Additional HART Protocol Information
Introduction
This appendix describes the HART protocol and provides references for
additional information about the protocol. Consult the HART protocol
specification and vendor-provided documentation for specifics on HART
commands.
This appendix provides the following:
• HART protocol background information
• Common practice command sets
• Extended command sets
• References to additional information
HART Field Communication Protocol is widely accepted in the industry as the
standard for digitally enhanced 4…20mA communication with smart field
instruments. The HART Protocol message structure, command set, and status
are discussed in this appendix.
The HART command set is organized into these groups and provides read and
write access to a wide array of information available in smart field instruments:
• Universal commands provide access to information that is useful in normal
plant operation such as the instrument manufacturer, model, tag, serial
number, descriptor, range limits, and process variables. All HART devices
must implement universal commands.
• Common practice commands provide access to functions that can be
carried out by many devices.
• Device specific commands provide access to functions that can be unique
to a particular device.