10 TROUBLESHOOTING
REMARK
The following are precautionary notes when exchanging data with an external device via one of the Q series C24 interfaces.
(1)When the power supply to the Q series C24 or external device is started, the remote device that is connected may generate a reception error.
(2)If the remote device that is connected starts up while data is being transmitted, the remote device side will generate a reception error.
(3)When the Q series C24 error LED lights up because a reception error has occurred, turn off the light if necessary in accordance with Section 10.1. Also, if a reception error has occurred on the external device side, handle the error by seeing to the operating manual for the external device.
Handle the occurrence of a reception error on the Q series C24 side using the following corrective actions.
• When communicating with the MC protocol
The Q series C24 will disregard the received data or returns a response message indicating an abnormal termination if it detects a reception error after receiving the head data of the command message in the set format. If the reception error is detected before the head data of the command message in the set format is received, the received data will be disregarded.
• When communicating using non procedure protocol
If the Q series C24 detects a reception error, the reception abnormal detection signal (X4, XB) turns ON.
Perform procedures such as detection of reception error or clearing received data as required by following the explanations found in Sections
6.1.4and 6.1.5.
•When communicating using bidirectional protocol
When the Q series C24 detects a reception error after the head data of a communication message for bidirectional protocol is received, it returns a response message indicating an abnormal termination.
If the reception error is detected before the head data of the communication message for bidirectional protocol is received, the received data will be disregarded.
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