Diagnostic Functions - ABB Relion 620 Series Protocol Manual

Section 3
Vendor-specific implementation
3.3.2
20
Function Name
code
05 Force single coil
06 Preset single register
08 Diagnostics
15 Force multiple coils
16 Preset multiple registers
23 Read/write holding registers

Diagnostic functions

The diagnostic functions are only intended for serial communication. However, the
serial diagnostic counters can be read, but not reset, via the Modbus TCP/IP interface.
The serial line cannot be forced to the listen mode via the Modbus TCP/IP interface.
Table 8: Supported diagnostic subfunctions
Function Name
code
00 Return query data
01 Restart communication option
04 Force listen only mode
10 Clear counters and diagnostic register
11 Return bus message count
12 Return bus communication error count
13 Return bus exception error count
14 Return slave message count
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1MRS757645 B
Description
Sets the status of a discrete output.
Sets the value of a holding register.
Checks the communication system
between the master and the slave.
Sets the status of multiple discrete outputs.
Sets the value of multiple holding registers.
Exchanges holding registers in one query.
Description
The data in the query data field is returned
(looped back) in the response. The entire
response is identical to the query.
The slaves peripheral port is initialized and
restarted and the communication event
counters are cleared. Before this, a normal
response will be sent provided that the port
is not in the listen only mode. If the port is in
the listen only mode, no response will be
sent.
The slave is forced to enter the listen only
mode for Modbus communication.
All counters and the diagnostic register are
cleared.
The response returns the number of
messages in the communication system
detected by the slave since its last restart,
clear counters operation or power up.
The response returns the number of CRC
errors encountered by the slave since its
last restart, clear counters operation or
power up.
The response returns the number of
Modbus exception responses sent by the
slave since its last restart, clear counters
operation or power up.
The response returns the number of
messages addressed to the slave or
broadcast which the slave has processed
since its last restart, clear counters
operation or power up.
Communication Protocol Manual
620 series