WAGO-I/O-SYSTEM 750
MODBUS – CODESYS 2 303
750-8207 PFC200 CS 2ETH RS 3G
Manual
Draft version 1.2.1 from 2017-09-13, valid from FW Version 02.06.20(09)
10.6 Diagnostics
10.6.1 Diagnostics for the MODBUS Master
The status of the PLC, or of the control system, can be queried by the MODBUS
master by reading the WAGO-specific register 0x1040 – “PLC Status” using
MODBUS services FC3 (Read Holding Registers) or FC4 (Read Input Registers).
The WAGO-specific register 0x1040 – “PLC Status” is explained in the Section
“PLC Status Registers”.
The status of the MODBUS Watchdog can be requested using a register service
(FC3 or FC4) with a query to the WAGO-specific register 0x1101 – “Watchdog
Status Register”. Information about this is given in the Section “MODBUS
Watchdog”.
The MODBUS service “Get Communication Event Counter” (FC11) is not
supported in the current MODBUS slave Version V1.0.
10.6.2 Diagnostics for the Runtime System
Diagnostics for the MODBUS slaves can be executed by integrating the
CODESYS library “BusDiag.lib” via the runtime system. The required function
block, “DiagGetBusState() indicates the status of the fieldbus (here MODBUS)
and is located in this library. Details about this function block are provided both in
this document and in the online Help function for CODESYS.
10.6.3 Diagnostics for the Error Server
The MODBUS slave also supports the error service implemented in the PFC and
generates diagnostic messages, which are stored permanently (in a file), or
temporarily (in the RAM) and can be displayed directly via the WBM client. The
following diagnoses are generated by the MODBUS slave:
Table 215: Diagnostics for the Error Server
Diagnostics
ID
Diagnostic text
Method of
saving
Explanation
0x00090000 Modbus Slave
library loaded
Temporary MODBUS slave library has
been successfully loaded.
0x00090001 Modbus Slave
library closed
Temporary MODBUS slave library has
been successfully unloaded.
0x00090002 Modbus Slave
TCP started
Temporary MODBUS slave successfully
started in TCP mode.
0x00090003 Modbus Slave
TCP start failed
Permanent Starting the MODBUS slave in
the TCP mode failed.
0x00090004 Modbus Slave
TCP terminated
Temporary MODBUS slave TCP mode
successfully terminated.
0x00090005 Modbus Slave
UDP started
Temporary MODBUS slave successfully
started in UDP mode.