SMC Networks LECSN-T Series User Manual

3. SIGNALS AND WIRING
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3.6.3 Vertical axis freefall prevention function
The vertical axis freefall prevention function avoids machine damage by pulling up the shaft slightly like the
following case.
When the servo motor is used for operating vertical axis, the servo motor lock and the base circuit shut-off
delay time function avoid dropping axis at forced stop. However, the functions may not avoid dropping axis a
few μm due to the backlash of the servo motor lock.
The vertical axis freefall prevention function is enabled with the following conditions.
Other than "0" is set to [Pr. PC31 Vertical axis freefall prevention compensation amount].
EM2 (Forced stop 2) turned off, an alarm occurred, or network communication shut-off occurred while
the servo motor speed is zero speed or less.
The base circuit shut-off delay time function is enabled.
(1) Timing chart
ON
ON
OFF
ON
OFF
ON
OFF
Electromagnetic brake
Release
Activate
Travel
distance
ON
Set the base circuit shut-off delay time.
([Pr. PC02])
EM2 (Forced stop 2)
Position
Base circuit
(Energy supply to
the servo motor)
MBR
(Electromagnetic
brake interlock)
OFF (Enabled)
OFF (Enabled)
Servo-on command
(from controller)
Ready-on command
(from controller)
(2) Adjustment
Set the freefall prevention compensation amount in [Pr. PC31].
While the servo motor is stopped, turn off the EM2 (Forced stop 2). Adjust the base circuit shut-off
delay time in [Pr. PC02] in accordance with the travel distance ([Pr. PC31). Adjust it considering the
freefall prevention compensation amount by checking the servo motor speed, torque ripple, etc.
3.6.4 Residual risks of the forced stop function (EM2)
(1) The forced stop function is not available for alarms that activate the dynamic brake when the alarms
occur.
(2) When an alarm that activates the dynamic brake during forced stop deceleration occurs, the braking
distance until the servo motor stops will be longer than that of normal forced stop deceleration without the
dynamic brake.
(3) If STO is turned off during forced stop deceleration, [AL. 63 STO timing error] will occur.
lock
upper side
upper side

SMC Networks LECSN-T Series Specifications

General

Brand	SMC Networks
Model	LECSN-T Series
Category	Controller
Language	English