88 Program featuresLimit to limit controlThe Limit to limit control function restricts the forward and reverse movement of aload inside two extreme points. The function supports the monitoring of two sensorsat both ends of the movement range: one for the slow down point and the other forthe stop point. The system installer must install the sensors (eg, limit switches) andconnect them to the drive.In the forward direction, the function allows normal operation of the drive until themovement reaches the forward limiting points:- When the drive receives the forward slow down signal, it decelerates the speedto the slow down speed. Slow down speed allows smooth transition to stop at alater stage. Vector mode uses the Speed reference ramp (23.11... 23.15) andScalar mode the Freq reference ramp (28.71... 28.75).- When the drive receives the forward stop signal, it stops the motor. It uses thedrive stop mode selection (21.03). The function allows start only in the reversedirection.In the reverse direction, the function monitors reverse slow down and reverse stopsignals. The operation is similar as in the forward direction.You can enable the function by a parameter, and define the signal sources for theforward slow down, forward stop, reverse slow down and reverse stop. You can alsodefine the slow down speed by a parameter.The Limit to limit function detects the signal status changes only when the function isactive, and the load is moved by the drive and motor. The function does not updatethe signal states in its state machine despite of the actual status changes:1. when the user has deactivated or disabled the function2. when the function has stopped the motor but the load is moved by a force otherthan the drive and motor (e.g., by a gravity).ParametersParameters: 21 Start/stop mode, 23 Speed reference ramp, 28 Frequency referencechain, 76.01 Limit to limit control status, 76.02 Limit to limit enable, 76.03 Limit to limitcontrol mode, 76.04 Forward stop limit, 76.05 Forward slow down limit, 76.06Reverse stop limit, 76.07 Reverse slow down limit, 76.08 Slow down speed, 76.09Slow down frequency.
