Mitsubishi MELSEC LJ71C24, User Manual

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6 SETTING AND WIRING
(Procedure 4) Checking loopback test result
Check on the external device whether the data received from the C24 in response to
the data received from the external device matches the data sent from the external
device.
(The C24 sends back to the external device the received data, as is.)
(1) When the result of the test is normal
The data received from the C24 in response to the data received from the
external device matches the data sent from the external device.
(2) When the result of the test is abnormal
The data received from the C24 in response to the data received from the
external device does not match the data sent from the external device.
(Procedure 5) Ending the loopback test
(1) When the result of the test is normal
Perform the following procedure according to the function used, and start data
communication.
•
Set the switch settings with GX Works2. (Refer to Section 7.3)
•
Turn on the station on which the C24 is installed.
(2) When the result of the test is abnormal
Confirm the following items, and take the corrective actions.
Item Corrective action
Examine the wiring connection of the
connection cable.
Check if the wiring connection of the connection cable is
correct.
(Refer to Sections 6.2 and 6.3)
Examine the C24 switch settings.
Check if the C24 switch settings (such as Transmission
Setting and Communication rate setting) match the
settings on the external device. (Refer to Section 7.3)
Check the error detection of the C24.
Check the error and take the corrective actions.
(Refer to Chapter 15)
An example of control procedure when the TT command is used in the loopback test
mentioned in Procedure 3.
(Station number: 00, sum check code: Exist)