Mitsubishi Electric MELSEC-Q/L Common Instruction

This error occurs in Basic model QCPU, High Performance model QCPU, Process CPU, and Redundant CPU when data, after being modified by an index register, attempts to write to a device reserved for system use. While device range checks aren't always conducted, writing to a system device specifically triggers this error, indicating a critical memory access violation and potential system instability.

This error occurs when the boot setting has not been configured in the PLC parameter, preventing the execution of a program replaced by the PSWAPP instruction. The system expects a program to be designated for boot. This ultimately prevents the newly swapped program from running, indicating a missing or incorrect system configuration for program execution.

This fault indicates that the drive number or file name specified in the (S1) or (S2) parameter of an instruction (such as PSWAPP) does not exist in the PLC memory or the specified storage location. This means the instruction cannot locate the required program file to perform its operation, leading to a failure in file manipulation or program execution.

This error indicates that the PLC's drive 0 (typically the program memory) does not have enough free space to load the specified program. This prevents program transfer operations, such as those performed by the PSWAPP instruction, from completing successfully. Insufficient memory can halt critical system updates or program changes.

This fault indicates an invalid device, drive number, or I/O number range has been specified, or a conflict with system-reserved memory locations. Specifically, for SORT/DSORT instructions, it means the user program attempted to use device points (D2) and (D2)+1 which are reserved by the system. For file operations like PSWAPP, it signifies an invalid drive number in (S1). When reading module information, it indicates n1 or n2 parameters are out of range or their sum exceeds the maximum allowed, preventing the operation from executing correctly.

This error indicates that an index modification operation has attempted to access a memory location beyond the defined boundaries of the file register (ZR), extended data register (D), or extended link register (W). This can lead to unexpected program behavior or data corruption if not addressed. The system will report this error when an out-of-range address is generated by an indexed device.

This error indicates that the value specified at parameter (S) for the SP.CONTSW instruction is 0. This is an invalid input parameter for the system switching command, which prevents the instruction from executing correctly and thus blocks any attempted system switching operation.

This fault occurs when the manual switching enable flag (SM1592) is OFF (disabled) at the time the SP.CONTSW instruction is executed. This configuration prevents manual system switching operations, effectively blocking the SP.CONTSW instruction from executing and causing the system to remain in its current state.

This error occurs if the SP.CONTSW instruction was executed by the standby system CPU module while operating in separate mode or if the instruction was executed when the CPU was in debug mode. Both scenarios represent prohibited conditions for performing system switching, preventing the instruction from completing successfully.

This operation error occurs when the CHK (Check) instruction is implemented improperly within the program, suspending CPU module operation. It can be caused by incorrect instruction placement between CHKST and CHK, exceeding the allowed number of CHK instructions, or attempting to use CHK/CHKST in a low-speed execution program. When this error occurs, the error flag SM0 turns ON and the error code is stored into SD0.

This code signifies various critical issues within a redundant system, including physical disconnections or faults in the tracking cable, hardware malfunctions, power interruptions, or watchdog timer errors in either the control or standby CPU. It also indicates communication timeouts, discrepancies in operating status between systems, or network faults, all of which compromise the integrity and operation of the redundant setup.