Laurel Electronics Modbus Protocol For Series 2 Laureate Digital Panel Meters, Counters, Timers & DIN-Rail Transmitters - Manual (Page 13)

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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
Sent
Response
Data
Description
00 00 Any Same 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 incre-
mented, 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.