D-82
FX Series PLC User's Manual - Data Communication Edition
Computer Link
9 Related Data
9.2 Details of Related Devices
9.2 Details of Related Devices
The devices described below are used for computer link.
9.2.1 Serial communication error [M8063 and M8438]
These devices turn ON when an error occurs during serial communication.
1. Detailed contents
These devices work as the serial communication error flags.
M8063 turns ON when an error occurs in serial communication in any PLC other than FX
3U and FX3UC PLCs
or in an FX
3U or FX3UC PLC using communication port ch1.
M8438 turns ON when an error occurs in serial communication in an FX
3U or FX3UC PLC using
communication port ch2.
When serial communication error flags turn ON, a corresponding error code is stored in D8063 and D8438.
9.2.2 Cautions on use
The serial communication error flag does not turn OFF even after communication recovers its normal status.
Clear it by switching the PLC mode from STOP to RUN.
9.2.3 Communication setting keep [M8120]
Set this device to ON in a sequence program so that the communication setting is kept (for FX0N PLCs).
1. Detailed contents
In an FX0N PLC, set M8120 to ON in a sequence program so that the communication format setting and
station number settings are kept.
2. Cautions on use
In an FX0N PLC, the communication setting status is kept only when M8120 is set to ON.
In any PLC other than FX
0N PLCs, setting of M8120 is not required.
9.2.4 Global function ON [M8126 and M8426]
These devices turn ON/OFF when the PLC receives the global command (GW) from personal computers.
1. Detailed contents
When the computer sends the global command, the global ON flag turns ON or OFF in all connected stations.
In all PLCs except FX
3U and FX3UC PLCs using communication port ch1, M8126 turns ON or OFF.
In FX3U and FX3UC PLCs using communication port ch2, M8426 turns ON or OFF.
2. Cautions on use
The global ON flag turns OFF from ON when the PLC power is turned OFF or when the PLC mode is
changed to STOP.
9.2.5 On-demand send processing [M8127 and M8427]
These devices remain ON while the on-demand function is being executed.
1. Detailed contents
When a PLC gives data sending request using the on-demand function, the on-demand send processing flag
turns ON.
In FX
2(FX), FX2C and FX2N(C) PLCs and in FX3U and FX3UC PLCs using the communication port ch2, M8127
turns ON/OFF.
In FX
3U and FX3UC PLCs using the communication port ch.2, M8427 turns ON/OFF.
2. Cautions on use
Use these devices for interlock to prevent generation of two or more on-demand requests at the same time.
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