Non-Blocking Errors

General

A non-blocking error is caused by an input/output error on the bus or through execution of an instruction. It can be processed by the user program and does not modify the PLC status.

Non-Blocking Errors Linked to Inputs/Outputs

Indication of a non-blocking error linked to the inputs/outputs is signaled by:

the processor’s I/O status LED on
the modules’ I/O status LEDs on
the error bits and words combined with the channel:
- bit %Ir.m.c.ERR at 1 indicates the channel at error (implicit exchanges)
- words %MWr.m.c.2 indicates the channel’s type of error (implicit exchanges)
system bits:
- %S10: input/output error on one of the modules on the rack bus
- %S16: input/output error in the task in progress
- %S118: input/output error on the CANopen bus
- %S40 - %S47: input/output error on address racks 0-7

The following table shows the diagnosis of non-blocking errors from the status LEDs and the system bits.

RUN Status LED	ERR Status LED	I/O Status LED	System Bit	Error
-	-	ON	%S10 at 0	Input/Output error: channel power supply error, broken channel, module not compliant with the configuration, inoperative or module power supply error.
-	-	ON	%S16 at 0	Input/output error in a task.
-	-	ON	%S118 at 0	Input/output error on the CANopen bus (the errors are the same as those of the bit %S10).
-	-	ON	%S40 - %S47 at 0	Input/output error in at rack level. (%S40: rack 0 - %S47: rack 7).
Key:
ON: LED on
-: Status undetermined

Non-Blocking Errors Linked to Execution of the Program

Indication of a non-blocking error linked to execution of the program is signaled by one or more system bits %S15, %S18, and %S20 being set to 1. The nature of the error is indicated in the system word %SW125 (always updated).

The following table shows the diagnosis of non-blocking errors linked to the execution of the program.

System Bit	Error
%S15 at 1	Character string manipulation error
%S18 at 1	Capacity overrun, error on a floating point or division by 0
%S20 at 1	Index overrun

NOTE: There are two ways to change non-blocking errors linked to the execution of the program to blocking errors:

Diagnostic program function, accessible through the Control Expert programming software
Bit %S78 (HALTIFERROR) when it is set to 1.

The processor’s HALT status is determined via the flashing ERR and I/O LEDs.

Testing and setting these system bits to 0 is the user’s responsibility.