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4.
SElTINGS AND PROCEDURES BEFORE OPERATION
MELSEC-A
Step 3
Execute the self-loopback test
(1) Turn the PC CPU power supply ON or reset the PC CPU.
The test starts automatically when the AJ71 C24 READY signal
turns ON. The READY signal turns ON a few seconds after the
power supply is turned ON or the PC CPU is reset.
(2) Check sequence
Checks are executed out in the following order:
1) PC CPU communications check
2) RS-232C communications check
3) RS-422 communications check
The checks are then repeated. The checks are completed
within one second. The checks are executed automatically
by the AJ71C24.
(3) Check the LED display status, as described in Section 4.6.2.
Normal : Follow procedure (4) t o end the test.
Error
: Correct the error and repeat the self-loopback test
(4) When checks are completed:
1) Turn the power supply OFF.
2) Disconnect the cables. Connect the cables to link with the
computers.
3) Change the setting of the mode setting switch.
("1"
to "D")
POINT(
When the AZA(S1) or A3ACPU is used, up to 6 AJ71C24 modules can be
connected to each PC CPU. When other types of PC CPUs are used,
1
or
2 AJ71C24 modules can be loaded to each PC CPU. However, do not
execute the self-loopback test with both modules simultaneously (this will
result in a PC CPU communications check error).
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