7 DATA COMMUNICATIONS USING 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 |
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A transmission error occurred because of noise. | — |
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A timeout occurred for the |
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| Section 6.1 | |
A timeout occurred for the response monitoring time (timer 1). | User's Manual |
| Section 6.2 | |
A timeout occurred for the transmission monitoring time (timer 2) | (Application) |
| Section 6.3 | |
Data that could not be converted with the |
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| Chapter 13 | |
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 device + 1
•ERR LED ON signal (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 storage area in the buffer memory (addresses 257H/267H).
For details on how to check the error code contents and corrective actions, see Chapter 10.
(b)How to turn off the ERR LED and clear the error code (see Section 10.1.2)
1)To turn off only the ERR LED, write a "1" to the LED OFF request area (addresses 0H/1H) in the buffer memory.
2)To turn off the ERR LED and clear the error code, turn ON the ERR LED OFF request output signal (YE/YF).
(Example) To perform the ERR LED OFF and the error code clear on the CH1 side:
Read command
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