Non-fatal errors are those that may degrade some aspect of PLC performance, but do not render the PLC incapable of executing the user program and updating I/O. To help you in debugging your program, information associated with error conditions is stored in special memory (SM) locations, which can be accessed by the user program. For example, if you do not want to continue in RUN mode with certain non-fatal error conditions, you can have the user program force a transition to STOP mode when the undesirable condition occurs.
The following table lists and describes the Special Memory non-fatal error information.
|SM Bit||Non-Fatal Error Description||SM Byte||Non-Fatal Error Description|
|SM0.2||Retentive Data Lost||SMB9||Module 0 I/O Error Byte|
|SM1.3||Divide by Zero Error||SMB11||Module 1 I/O Error Byte|
|SM3.0||Parity Error||SMB13||Module 2 I/O Error Byte|
|SM4.0||Comm. Interrupt Queue Overflow||SMB15||Module 3 I/O Error Byte|
|SM4.1||Input Interrupt Queue Overflow||SMB17||Module 4 I/O Error Byte|
|SM4.2||Timed Interrupt Queue Overflow||SMB19||Module 5 I/O Error Byte|
|SM4.3||Run-Time Programming Problem||SMB21||Module 6 I/O Error Byte|
|SM5.0||I/O Error (any I/O error bit set)|
|SM5.1||Too many digital points|
|SM5.2||Too many analog points|