C4 User Manual
Page 112 ©2021 Smartrise Engineering, Inc. All Rights Reserved October 25, 2021
• Verify Motor RPM #11 matches the motor manufacturer name plate. If the car is
traveling faster than commanded then reduce this value, if too slow then increase it.
• Check Per-Unite Inertia #41 value is not set too low which will result in velocity
overshoot. If value is set too high, it will result in velocity undershoot.
Motor Current Limiting – If running out of motor current near the end of Acceleration becomes
a problem, as is evidenced by the AC motor current on the drive keypad during a full load UP
operation:
• F5 Drive – Set parameter LC.30 Maximum Torque = 300 (3x LF.17). This will
automatically adjust the current limit.
• Magnetek – Increase A1 > Mtr Torque Limit.
• If this does not help, reduce the value of Acceleration. Another possibility is to
decrease the value of accel jerk out so that there is a smooth transition from
maximum acceleration to contract speed.
• Slope of Acceleration / Deceleration – Ideally, the slope of acceleration should be
equal to or slightly greater than the slope of deceleration. To get approximately
equal acceleration and deceleration speeds in a system where tracking accuracy is
very good, Acceleration can be equal to Deceleration. If tracking is less accurate, set
Acceleration greater than Deceleration to get the same effective rate of deceleration
as acceleration.
Approaching the Floor – Final approach to the floor can be customized in many different ways.
If tracking accuracy is very good, you can set the following:
• Leveling Speed – The desired leveling speed. A typical number is from 2 to 5. See
section 13.5 Leveling Speed.
• Leveling Distance – The distance of choice. A typical number is from 1 to 2. See section
9.1.1.7 Leveling Distance.
If ideal tracking is not obtained, begin to introduce values in the Leveling Speed and
Distance that allows for molding the shape of the last few inches of approach.
Increase in Deceleration Rate – If observing an increase of deceleration as the floor is
approached, it is generally due to inaccurate tracking.
• Improve tracking or lower the value of the Deceleration parameters.
9.8 Controlling Initial Start of Car Motion
Gearless application may experience rollback at the start of car motion. To control rollback at
the start of the run:
• Implement pre-torque to the system
• Make brake adjustments
• Apply synthetic speed torque
• Adjust run timers
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