Rockwell Automation 1797-OE8H FLEX Ex HART Analog Modules User Manual - Manual (Page 125)

1 Publication 1797-6.5.3 - March 2006
Appendix
B
FLEX Ex HART Module Commands
What This Appendix
Contains Read this appendix to learn the module commands to and from FLEX Ex
HART I/O modules.
Protocol Overview HART field communication protocol is widely accepted in the industry as the
standard for digitally enhanced 4…20 mA communication with smart field
instruments. The HART protocol message structure, command set, and status
are explained in this appendix.
The HART command set is organized into three groups and provides
read/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, though not all.
• Device-specific commands provide access to functions that may be
unique to a particular device.
For See
Protocol Overview B-1
Universal Commands B-2
Common Practice Commands B-3
Device-specific Commands B-3