Mitsubishi Electronics QJ71C24/-R2, QJ71C24N, SH-080007 manual 271

10 TROUBLESHOOTING

MELSEC-Q

Error code							Protocol
	Error		Signal				Non
(Hexa-		Error Contents			Corrective action			Bidire-
			name			MC	Proce-
decimal)								ctional
							dure
7F24H	Sum check error	• The sum check calculated by the Q series C24 and	P/S	• Recheck the external device
		the received sum check are not the same.			sum check.
				• Correct the "data length" that is
					transmitted from the external
		• The length of the received data exceeds the receive	CHn		device.
7F25H	Data length error			•	Change the "word/byte units"
		area size.	ERR.		set by the Q series C24 to byte
					units.
				• Increase the receiving area of
					the Q series C24.
		• Another command was received before an unlock	CHn	•	Perform the communication
7F26H	Command error				after the unlock processing is
		processing while the remote password is registered.	ERR.
					normally completed.
7F30H	System error	• The OS of the Q series C24 detected some error.	—	(	1)
				• Process by agreement with the
					external device.
	Simultaneous	• The Q series C24 and an external device started		• When necessary, change the
7F31H					simultaneous transmission data
	transmission error	transmitting simultaneously.
					valid/invalid designation setting
					by GX Configurator-SC. (buffer
					memory addresses 9BH/13BH)
7F32H	System error	• The OS of the Q series C24 detected some error.	—	(	1)
		• No reception watchdog timer (timer 0) time-out		• Check if data was dropped from
7F40H			PRO		the receive data.
		occurred.		•	Check if DTR control, etc.
					interrupted reception.
	Time-out error	• Response watchdog timer (timer 1) time-out		• Check the status of the
7F41H					message transmission
		occurred.			destination and restart data
					communications, as required.
7F42H		• Transmit watchdog timer (timer 2) time-out		• Check if DTR control, etc.
		occurred.			interrupted transmission.
7F50H
to
7F54H	System error	• The OS of the Q series C24 detected some error.	—	(	1)
7F60H
to
7F66H
				• Decrease the data transmission
					rate and restart data
					communications.
		• The Q series C24 received the next data before it		• Check whether a temporary stop
7F67H	Overrun error		SIO		has occurred in the station in
		completed receive processing of the previous data.			which the Q series C24 is
					installed. (For the QCPU this can
					be checked using special register
					SD1005.) If a temporary stop has
					occurred, remove its cause.
				• Match the Q series C24 and
					external device settings.
				• Clear the error information
					according to the error
					information initialization request
		• Data does not match the stop bit setting.			(YE/YF).
					In addition, when
		• A malfunction occurred in the network because the
					communicating data with the
		power source of the partner station was on or off.
7F68H	Framing error		SIO		non procedure protocol, execute
		• Noise occurs in the network.
					the INPUT instruction, and read
		• When the multidrop was connected, data was
					and discard the unnecessary
		transmitted simultaneously by multiple devices.
					data.
				•	Measure the noise.
				• When connecting the multidrop,
					remove the interlock so that
					data will not be transmitted
					simultaneously by multiple
					devices.

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