GE PACSystems RX7i Reference Manual page 255
Cpu
Hide thumbs
Also See for PACSystems RX7i:
- User manual (276 pages) ,
- Cpu programmer's reference manual (469 pages)
Table of Contents
Advertisement
Chapter 6. Serial I/O, SNP & RTU Protocols
Response:
▪
See descriptions for individual Diagnostic Codes.
Diagnostic Return Query Data Request (Loopback/Maintenance Code 00):
▪
An address of 0 is not allowed for the return query data request.
▪
The values of the two Data field bytes in the query are arbitrary.
▪
The normal response is identical to the query.
▪
The values of the Data bytes in the response are equal to the values sent in the query.
Diagnostic Initiate Communication Restart Request (Loopback/Maintenance Code 01):
▪
An Address of 0 indicates a broadcast request. All slave stations process a broadcast request and no
response is sent.
▪
This request disables the listen-only mode (enables responses to be sent when queries are received
so that communications can be restarted).
▪
The value of the first byte of the Data field (DATA1) must be 0 or FF. Any other value will cause an
error response to be sent. The value of the second byte of the Data field (DATA2) is always equal to
0.
▪
The normal response to an Initiate Communication Restart query is identical to the query.
Diagnostic Force Listen-Only Mode Request (Loopback/Maintenance code 04):
▪
An Address of 0 indicates a broadcast request. All slave stations process a broadcast request.
▪
After receiving a Force Listen-Only mode request, the RTU device will go into the listen-only mode,
will not perform a requested function, and will not send either normal or error responses to any
queries. The listen-only mode is disabled when the RTU device receives an Initiate Communication
Restart request or when the RTU device is powered up.
▪
Both bytes in the Data field of a Force Listen-Only Mode request are equal to 0. The RTU device never
sends a response to a Force Listen-Only Mode request.
Note: Upon power-up, the RTU device disables the listen-only mode and is enabled to continue
sending responses to queries.
244
PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
GFK-2222AD
- Quick Links:
- Rx7I Overview
Hide quick links:
Advertisement
Table of Contents
