Laurel Electronics LTM DPM SERIES ANALOG INPUT, SERIAL DATA OUTPUT - Manual (Page 28)

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FC08: Diagnostics
Checks communications between the Master and Slave, and returns the count in the Modbus
Slave counters (which are reset when the meter is reset).
Hex Sub
Function
Code
Data
Send
Response
Data
Description
00 00 Any Same
as sent
Returns Query Data (N x 2 bytes). Echo Request.
00 01
FF 00
00 00
FF 00
00 00
Restarts Communications. If in the Listen-Only mode, no
response occurs. Takes Slave out of the Listen-Only mode
and one of the following:
Clears communications event counters.
Does not clear communications event counters.
00 04 00 00 None Forces Listen-Only. All addressed and broadcast
Messages are monitored and counters are incremented,
but no action is taken or response sent. Only Sub-
Function 00 01 causes removal of this Listen-Only state.
00 0A 00 00 00 00 Clears all Modbus slave counters.
00 0B 00 00 Total
Message
Count
Returns total number of messages detected on the bus,
including those not addressed to this Slave. Excludes bad
LRC/CRC, parity error or length < 3.
00 0C 00 00 Checksum
Error
Count
Returns total number of messages with bad LRC/ CRC,
parity or length < 3 errors detected on the bus including
those not addressed to the Slave.
00 0D 00 00 Exception
Error
Count
Returns total number of Exception responses returned by
the Addressed Slave or that would have been returned if
not a broadcast message or if the Slave was not in a
Listen-Only mode.
00 0E 00 00 Slave
Message
Count
Returns total number of messages, either broadcast or
addressed to the Slave. Excludes bad LRC/CRC, parity or
length < 3 errors.
00 0F 00 00 No
Response
Count
Returns total number of messages, either broadcast or
addressed to the Slave, for which Slave has returned No
Response, neither a normal response nor an exception
response. Excludes bad LRC/CRC, parity or length < 3
errors.
00 11 00 00 Slave
Busy
Returns total number of Exception Code 6 (Slave Busy)
responses.