Mitsubishi MELSEC QJ71C24, User Manual

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MELSEC-Q
7 DATA COMMUNICATION USING THE BIDIRECTIONAL PROTOCOL
7.2.4 How to detect transmission errors
This section explains how to detect errors that may occur when sending data to the
external device.
The following items are considered as the primary causes of errors that may occur
during data transmission.
Cause of transmission error Reference section
A transmission error occurred because of noise. —
A timeout occurred for the no-reception monitoring time (timer 0).
A timeout occurred for the response monitoring time (timer 1).
A timeout occurred for the transmission monitoring time (timer 2).
Data that could not be converted with the ASCII-BIN conversion was detected.
User's Manual (Application)
Designated the transmission data count that exceeded the transmission area size. Section 7.2.2
Simultaneous transmissions occurred. Section 7.3
(1) Confirmation using the sequence program
(a) Detecting a transmission error
1) The following device and input signal turn ON.
• BIDOUT instruction complete 1
• ERR. occurrence (XE/XF)
2) The transmission error code can be checked using the BIDOUT
instruction control data ((S1) + 1).
Or, it can be checked by reading the data transmission result (address:
257
H
/267
H
).
For details on how to check the error code contents and corrective
actions, see Chapter 11.
(b) How to turn off the ERR LED and clear the error code (see Section 11.1.2)
1) To turn off only the ERR LED, write a "1" to the Communication error
clear request and to turn LED off (address: 0
H
/1
H
).
2) To turn off the ERR LED and clear the error code, turn ON the ERR.
clear request (YE/YF).
(Example) To perform the ERR LED OFF and the error code clear on
the CH1 side:
Read command