Parker 8903/RS, Technical Manual

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8903/RS RS485 Communications Interface
07 Read Exception Status
This function reads the last exception code transmitted in an error response or 0 if a normal
response was transmitted. This function does not modify the exception status itself.
Request:
Function code 1 byte 0x07
Response:
Function code 1 byte 0x07
Exception status 1 byte 00, 01, 02, 03
08 Diagnostics
This function provides a series of diagnostics for checking the communication status of the
slave. It uses a two-byte sub-function code field in the request to define the diagnostic required.
Request PDU:
Function code 1 byte 0x08
Sub-function code 2 bytes See below
Data 2 bytes
Response:
Function code 1 byte 0x08
Sub-function code 2 bytes See below
Data 2 bytes
Error Response:
Function code 1 byte 0x88
Exception code 1 byte 01
Sub-functions:
Sub-function code Function Description
00 00 Query data
(loopback) Responds with the two data bytes
00 02 Return diagnostic
register Responds with the last error exception
transmitted
00 10 Clear Counters and
Diagnostic Register Clears the status and error registers and resets
all error counters
00 12 Return Bus
Communications Error
Count Responds with the CRC error count
00 13 Return Bus Exception
Count Responds with the exception count
Other Not supported Responds with error response
(Illegal Function)
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