Rockwell Automation 1797-OE8H FLEX Ex HART Analog Modules User Manual - Manual (Page 188)

Publication 1797-6.5.3 - March 2006
F-4 FLEX Ex HART Modules Network Messaging
Handle replaces Preamble. Handle is a number you supply so that the module
returns the Handle with the associated response from the HART command.
The response from the HART command is reformatted to add this handle and
to add additional status information.
Figure F.4 Response from the HART Command
The six header bytes are added in the front of the HART message response
while the remaining format is unchanged. These six bytes contain the
following information:
• Response Source
• Next Assembly
Pointer to assembly for next access.
• Channel
Status
(6 Bytes) Pass
Through
Handle Start
Character Address Command Byte Count (Response
Code) Data Checksum
Byte 0 1 2 3 4 5
Bit 0…2 3…7 0…7 0…7 0…7 0…3 4 5 6 7 0 1 2…7
Resp
Source
Next assy index Ch Handle Resp
Error Assy
Access
Error
Chain
Data
Req
allow
Loop
status
avail
Lock Cold
Start
Res
Value Meaning
0 Not valid (default)
1 Source is HART response
2 Source is Scan data
3 CMD 48 response
4…7 Reserved