Fault Behavior; Fieldbus Failure; Internal Bus Fault - WAGO -I/O-SYSTEM 750 User's Installation And Configuration

3.1.8

Fault behavior

3.1.8.1

Fieldbus failure

A field bus failure is given i. e. when the master cuts-out or the bus cable is
interrupted. A fault in the master can also lead to a fieldbus failure.
A field bus failure is indicated when the red "ERROR"-LED is illuminated.
If the watchdog is activated, the fieldbus coupler firmware evaluates the
watchdog-register in the case of fault free communication, and the coupler an-
swers all following MODBUS TCP/IP requests with the exception code
0x0004 (Slave Device Failure).
i
More information
For detailed information on the Watchdog register see Chaper 6.2.12
"Watchdog (Fieldbus failure)".
3.1.8.2

Internal bus fault

An internal bus fault is created, for example, if an I/O module is removed. If
this fault occurs during operation the output modules behave in the same man-
ner as an I/O module stop. The "I/O" LED blinks red.
The coupler generates a fault message (fault code and fault argument).
After clearing the internal bus fault, restart the coupler by cycling the power.
The coupler starts up. The transfer of the process data is then resumed and the
node outputs are correspondingly set.
Modular I/O System
ETHERNET TCP/IP
Fieldbus coupler 750-342 • 45
Fault behavior