Specifications

Chapter 7 Trouble shooting
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Over load (release: possible)
● Description
The driver always monitors the motor current and if the current exceeds the curve in the figure below,
then an overload alarm occurs.
For example:
(1) The alarm occurs if the current is 1.2 times of
nominal for a long period of time.
(2) The alarm occurs if the current of three times
of the nominal current flows for 20 seconds.
It is possible to release the alarm by inputting the
ON signal to [CN2-2 clear: CLEAR], if the overload
condition has been corrected.
● Diagnostic tips
(1) Alarm occurs when control power
is turned on:
◆ Cause 1: The control circuit of the HA-655 driver
may have failed.
⇒Remedy: Contact harmonic drive systems.(Replace the HA-655 driver)
(2) Alarm occurs when servo power is turned on:
◆ Cause 1: The encoder connector (CN1) may not be connected.
⇒Remedy: Verify connection of encoder connector (CN1).
(3) The alarm occurs while running (it is possible to restart after shutting off
control power):
◆ Cause 1: Running at over load state
⇒Remedy: Review the actuator’s actual load profile to lower the duty.
(4) Alarm occurs after hunting motion:
◆ Cause 1: Hunting motion is caused by poor gain adjustment
⇒Remedy: Adjust gains in [tune mode]→[0: speed loop gain],[1: speed loop integral
compensation] and [2: position loop gain] proportional to the load.
(5) Alarm does not occur when driving the actuator only (no load), but alarm
occurs with load:
◆ Cause 1: Wrong connection of motor and encoder cables
⇒Remedy: Connect cables correctly referring to [chapter 4 : Installing the HA-655 driver] in
this manual.
(6) Alarm occurs when driving the actuator only (no load):
◆ Cause 1: Wrong connection of motor and encoder cables
⇒Remedy: Connect cables correctly referring to [chapter 4: Installing the HA-655 driver] in
this manual.
Continuous
current
Actuator current
1000
1
00
1
0
1.2 times of
nominal current
Delay (s)
×1 ×2 ×3
Over load range