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7
DATA COMMUNICATION USING THE BIDIRECTIONAL PROTOCOL
7.1.4 How to detect reception errors
A transmission error occurred because of noise.
A timeout occurred for the no-reception monitoring time (timer 0).
A timeout occurred for the transmission monitoring time (timer 2).
Data that could not be converted with the ASCII-BIN conversion was detected.
Received the data length that was too long to store in the receiving area.
Simultaneous transmissions occurred.
Read command
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This section explains how to detect errors that may occur when receiving data from the
external device.
The following items are considered as the primary causes of errors that may occur
during data reception.
Cause of reception error
(1) Confirmation using the sequence program
(a) Detecting the occurrence of a reception error
1) ERR. occurrence is on.
2) The receive error code is confirmed and read in data reception result
(address: 258
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
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
/268
).
H
H
the CH1 side
MELSEC-Q
Reference section
—
User's Manual (Application)
Section 7.1.2
Section 7.3
/1
).
H
H
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