PLC Non-Fatal Error Memory Locations

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