Errors; 5.1 Fx3S/Fx3G/Fx3Gc/Fx3U/Fx3Uc Plcs; Error Detection Devices - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
5.

Errors

This chapter explains error codes stored in special data registers when program errors occur in the PLC, and
actions to be taken against errors.
Support of error detection devices depends on the PLCs.
5.1 FX /FX /FX
3S 3G
5.1.1

Error detection devices

1. Error detection (M8060 and later and D8060 and later)
When some devices among M8060, M8061 and M8064 to M8067 turn ON, D8004 stores the smallest device
number and M8004 turns ON.
1) M8060, M8061 and M8064 to M8067 are cleared when the PLC mode switches from STOP to RUN.
Note that M8068 and D8068 are not cleared.
2) When M8069 is set to ON, the PLC will enter the STOP mode (M8061: PLC hardware error) if a failure
occurs in an I/O extension unit, extension power supply unit or function block.
When M8069 is set to ON, the PLC executes the I/O bus check. If an error is detected, D8061 stores the
error code ("6103" or "6104") and M8061 turns ON.
When D8061 stores "6104", M8009 turns ON and D8009 stores the I/O numbers connected after the
extension power supply unit where 24V DC power failure has occurred.
This function is available only in FX
3) When units and blocks having programmed I/O numbers are not actually connected, M8060 turns ON
and D8060 stores the head device number of unconnected units/blocks.
This function is available only in FX
Example: When X020 is unconnected
1 0 2 0
*1. 10 to 337 in FX
4) When an I/O device number is directly specified or indirectly specified using index registers for the LD,
AND, OR or OUT instruction, and if the specified I/O device number is not actually connected, M8316
turns ON, and D8317 (high-order bits) and D8316 (low-order bits) store the error step number in the
instruction.
This function is available only in FX
/FX /FX PLCs
3GC 3U 3UC
, FX
3G 3GC
, FX
3G 3GC
Value converted into BCD
*1
Device number
1:Input X 0:Output Y
/FX PLCs, and 10 to 177 in FX
3U 3UC
and FX
3U

5.1 FX3S/FX3G/FX3GC/FX3U/FX3UC PLCs

→ For details, refer to Section 4.1.
, FX , and FX PLCs.
3U 3UC
, FX , and FX PLCs.
3U 3UC
/FX PLCs
3G 3GC
PLCs.
3UC
5 Errors
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