Mitsubishi MELSEC-A A1SD71-S2 User Manual page 36

3. SPECIFICATIONS
MELeEeA
(b) Mechanical stop (1) (caused by a dwell time time-out)
After a near-point dog has operated and the dwell time has passed,
zero return is completed. (Refer to Fig. 3.13-1
.)
In this case, if the dwell time has not passed, even if the near-point
dog goes OFF halfway, zero return is not completed. After reaching
the cwep speed, limit the servo motor torque (Section 3.4.2(7) gives
details).
If
the servo motor torque is not limited, the servo motor may malfunc-
tion when a stopper is hit.
* ,
n e a y i n t dog ON
Zero return speed
Deceleration by stop by stopper
/
After the dwell time times out.
the zero return complete signal
goes ON.
I
/
I
I
Near-point dog
I
Range in which the servo
Dwell time motor rotation is forcibly
count start
,
stopped by the stopper
A
Dwell time
I
I
Zero return torque limit valid
Torque limit valid range
Fig. 3.13-1 Zero return by Using Stopper Stop (1)
(c) Mechanical stop (2) (caused by an external stop command)
This is the method of stopping by inputting an external stop com-
mand when a servo motor interferes with the stopper. (Refer to Fig.
Forcibly input a zero-phase signal (stop command) to the zero-phase
signal terminal by an external switch after the near-point dog goes
ON.
3.13-2.)
When inputting a zero-phase signal (stop command), the ON/OFF
state of the near-point dog is not problem.
After reaching the creep speed, limit the servo motor torque (Section
3.4.2 (7) gives details).
If
the servo motor torque is not limited, the servo motor may malfunc-
tion when a stopper is hit.
Deceleration by near-point dog ON
Creep speed
Stop by stopper
Stop command to the zero-
phase signal terminal
Zero return torque limit valid
4
4
Torque limit valid range
Fig. 3.13-2 Zero return Uslng
a
Stopper
If a stop signal is input before the speed decelerates to the creep speed, excessive power is
deljvered to the servo motor and machine system, causing a fault.
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