Motion fault limit paremeter

From Granite Devices Knowledge Wiki
Revision as of 09:51, 17 July 2012 by Tero K (Talk | contribs)


Jump to: navigation, search

The parameter called motion fault limit controls a safety faulting mechanism of GD servo drives.

Usage

Motion fault attempts to detect incorrect motor behavior and sets drive in fault state (and stop driving motor) in case of abnormal motion condition. The motion fault will help to detect following fault scenarios:

  • DC motor runaway when feedback is lost
  • Motion blocked by obstacle (can react faster than following/tracking error fault)
  • Detect stall of stepping motor

How it works

Motion fault monitors three variables to determine fault:

  • Actual velocity
  • Time
  • Output torque/current

Drive activates fault if output current is greater than set threshold value for over 0.2 second period and simultaneously velocity stays below a fixed threshold.

Parameters

Motion fault has only one changeable parameter: threshold. The threshold value controls the current level which must be exceeded to activate 0.2 second timer and velocity monitor.

Finding correct value

Correct value can be found by experimenting.

  1. Set threshold to low starting value such as 500
  2. Give settings a try and observe if motion fault occurs in normal use
  3. If fault occurs, increase threshold until it stops happening (one may add some safety headroom after this point is reached to increase margin for rare errors)
  4. Simulate some fault cases to ensure that fault triggers properly (such as disconnect feedback or block motion). If fault doesn't occur reliably, decrease threshold.

In no event the Product Information or parts hereof shall be regarded as guarantee of conditions or characteristics. The Product Information or any part thereof may also not be regarded as a warranty of any kind. No liability of any kind shall be assumed by Author with respect to Product Information or any use made by you thereof, nor shall Author indemnify you against or be liable for any third party claims with respect to such information or any use thereof.

As content of this Wiki may be edited by user community, Granite Devices Oy or it's affiliates do not take any responsibility of the contents of this Wiki. Use information at your own risk. However, Granite Devices staff attempts to review all changes made to this Wiki and keep information trustworthy.

Without written consent, Granite Devices' Products or Intellectual Property shall not be used in situations or installations where living beings, material property, or immaterial property could be harmed by the operation, features or failures of Product. Products may only be used in a way where hazards like moving parts, electric shock, laser radiation, or fire can't be realized even if the content of this Wiki would suggest otherwise.