NO
YES
YES
Start
Is power
LED lit?
• Check connection with the PC.
• Check power source of PC.
Is the send
data remainder
zero?
NO
YES
NO
Is send
wait flag M8121
turned on?
Is SD LED
(send) lit up
momentarily?
1
YES
Only receiving
fails to operate
normally
NO
• Check the timing of control line.
• Check the wiring of RS232C cable.
• Check the wiring of control line.
• Match the communication format.
• Make sure the receiving external device is normal.
(CR, LF may be needed in some printers.)
• Check the data format of sending device.
YES
• Check wiring of RS232C cable.
• Check wiring of control line.
• Make sure the receiving external device is normal.
• Check the voltage level of RS232C signal (±9 V).
• Make sure content of send data and communication format
are established before driving RS instruction.
NO
• Check wiring of control line.
• Check timing of send, receive.
• Change RS instruction from OFF to ON.
• Make sure the received data length matches with the receive
data area length.
NO
Is M8063
turned on?
• There is a possibility of send crosstalk. Check the send and receive
timing with the external RS232C device.
• The receive data length may exceed the receive data area.
Check the receive data length and timing of receive start.
• Check that the program is not set so that M8122 may be always on.
• Match the communication format.
• Check the wiring of control line.
• Check the start timing of send, receive.
No send
or receive
error
No send or receive error
Send,
receive
error
YES
NO
The data
transfer
complates
once.
NO
• Eliminate VRRD. VRSC
instruction and reset power source.
NO
• Reset M8070, M8071, and
reset power source.
YES
YES
Is VRRD
VRSC
instruction
used?
Are M8070,
M8071
turned on?
YES
}
Note: Only one of the following de-
vices can be connected to
the communications port on
the left of the PC:
FX-8AV, FX2-40AW,
FX2-40AP, FX-232ADP.
FX-485ADP
