Mitsubishi Electronics MR-J2S- A instruction manual Power supply of CN1 cabling is

10. TROUBLESHOOTING

10.1.2 Speed control mode

No.	Start-up sequence	Fault	Investigation	Possible cause	Refer to
1	Power on	LED is not lit.	Not improved if connectors	1. Power supply voltage fault
		LED flickers.	CN1A, CN1B, CN2 and CN3	2. Servo amplifier is faulty.
			are disconnected.
			Improved when connectors	Power supply of CN1 cabling is
			CN1A and CN1B are	shorted.
			disconnected.
			Improved when connector	1. Power supply of encoder
			CN2 is disconnected.	cabling is shorted.
				2. Encoder is faulty.
			Improved when connector	Power supply of CN3 cabling is
			CN3 is disconnected.	shorted.
		Alarm occurs.	Refer to Section 10.2 and remove cause.		Section 10.2
2	Switch on servo-on	Alarm occurs.	Refer to Section 10.2 and remove cause.		Section 10.2
	signal.	Servo motor shaft is	1. Check the display to see if	1. Servo-on signal is not input.	Section 6.6
		not servo-locked	the servo amplifier is	(Wiring mistake)
		(is free).	ready to operate.	2. 24VDC power is not
			2. Check the external I/O	supplied to COM.
			signal indication to see if
			the servo-on (SON) signal
			is ON.
3	Switch on forward	Servo motor does	Call the status display and	Analog speed command is 0V.	Section 6.2
	rotation start (ST1)	not rotate.	check the input voltage of
	or reverse rotation		the analog speed command
	start (ST2).		(VC).
			Call the external I/O signal	LSP, LSN, ST1 or ST2 is off.	Section 6.6
			display and check the
			ON/OFF status of the input
			signal.
			Check the internal speed	Set value is 0.	(1), Section
			commands 1 to 7		5.1.2
			(parameters No. 8 to 10 72
			to 75).
			Check the internal torque	Torque limit level is too low as
			limit 1 (parameter No. 28).	compared to the load torque.
			When the analog torque	Torque limit level is too low as
			limit (TLA) is usable, check	compared to the load torque.
			the input voltage on the
			status display.
4	Gain adjustment	Rotation ripples	Make gain adjustment in the	Gain adjustment fault	Chapter 7
		(speed fluctuations)	following procedure:
		are large at low	1. Increase the auto tuning
		speed.	response level.
			2. Repeat acceleration and
			deceleration several
			times to complete auto
			tuning.
		Large load inertia	Make gain adjustment in the	Gain adjustment fault	Chapter 7
		moment causes the	following procedure:
		servo motor shaft to	If the servo motor may be
		oscillate side to side.	run with safety, repeat
			acceleration and
			deceleration several times
			to complete auto tuning.

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