If somebody has experience with AC30 parameters PNO 0505 Zero Speeed Threshold and PNO 0506 Zero Speed Stop Delay, could you please illustrate by an example, how can we benefit changing them?
Hello Dusan. Yes, both of these are used for a similar purpose. When the AC30 decelerates a motor to zero speed, it needs a way to determine when to report that zero speed has been achieved. Depending on the mode in which the drive is operating, different approaches will be used:
The Zero Speed Threshold allows the user to specify a speed below which the drive should assume it has successfully stopped the motor. This is especially important with drives in SLV or CLV since their feedback may not ever truly report zero speed. The default is 0.1% and this is fine for most applications. You may consider increasing it if you are having trouble getting the drive to report zero speed.
The Zero Speed Stop Delay works together with the Zero Speed Threshold. Once the motor decelerates below the Zero Speed Threshold, the drive waits the amount of time specified by the Zero Speed Stop Delay before signalling that the motor has stopped. The idea is that this delay should be long enough so that the motor will definitely have stopped. The default is 0.5 seconds. You might consider increasing it a little if you have a very large inertial load and very little friction in your machine (e.g. flywheel, centrifuge). You could also decrease it to reduce cycle time.
For most applications, you can leave these parameters at default. I would only change them under one of the following conditions:
I hope this helps. Please let us know if you have any questions.