Vertical Axis Freefall Prevention Function; Setting Method [G] [Wg]; Setting Method [A] - Mitsubishi Electric MELSERVO-J5 Series User Manual

3.17

Vertical axis freefall prevention function

When the servo motor is used to operate a vertical axis, the servo motor electromagnetic brake and the base circuit shut-off
delay time function can be used to prevent the vertical axis from dropping at forced stop; however, the axis may fall by several
μm due to mechanical clearance of the servo motor electromagnetic brake. The vertical axis freefall prevention function is a
function that is used to prevent fall-based damage to the machine by pulling up the shaft slightly when such a risk exists.
• Once each of the servo parameters is set, this function operates when the servo motor speed is at or below
the zero speed, the EM2 (forced stop 2) is off, an alarm occurs, or the network communication shuts off.
• This function does not operate on alarms that are not subject to the forced stop deceleration function.
• This function can be used in the position mode and homing mode.
Precautions
• Refer to the setting method shown in this section, and check if each servo parameter has been set. If not set, this function
does not operate.
• Check that the forced stop deceleration function is enabled. If disabled, this function does not operate.

Setting method [G] [WG]

Set the freefall prevention compensation amount with [Pr. PC31 Vertical axis freefall prevention compensation amount].
After that, turn off the EM2 (Forced stop 2) during a servo motor stop, then adjust the base circuit shut-off delay time in [Pr.
PC02 Electromagnetic brake sequence output] in accordance with the travel distance ([Pr. PC31 Vertical axis freefall
prevention compensation amount]). Adjust the time considering the freefall prevention compensation amount by checking the
servo motor speed, torque ripple, and other areas.
Servo Symbol
parameter
PC02 MBR
PC31 RSUP1

Setting method [A]

Set the freefall prevention compensation amount with [Pr. PC54 Vertical axis freefall prevention compensation amount].
After that, turn off the EM2 (Forced stop 2) during a servo motor stop, then adjust the base circuit shut-off delay time in [Pr.
PC16 Electromagnetic brake sequence output] in accordance with the travel distance ([Pr. PC54 Vertical axis freefall
prevention compensation amount]). Adjust the time considering the freefall prevention compensation amount by checking the
servo motor speed, torque ripple, and other areas.
Servo Symbol
parameter
PC16 MBR
PC54 RSUP1
Name
Electromagnetic brake sequence
output
Vertical axis freefall prevention
compensation amount
Name
Electromagnetic brake sequence
output
Vertical axis freefall prevention
compensation amount
Outline
Set the base circuit shut-off delay time.
Initial value: 0 [ms]
Set the freefall prevention compensation amount.
Initial value: 0 [0.0001 rev], [0.01 mm]
Outline
Set the base circuit shut-off delay time.
Initial value: 0 [ms]
Set the freefall prevention compensation amount.
Initial value: 0 [0.0001 rev], [0.01 mm]
3.17 Vertical axis freefall prevention function
3 BASIC FUNCTION
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