6K Troubleshooting - Why Is My Motion Jerky/Erratic/Not Smooth?

Owned by Jack Degrano
Last updated: Jun 28, 2024 by Eric Rojas (Unlicensed)
2 min read

There can be many causes of jerky motion.  First, make sure that the mechanical system is smooth.  

If the mechanics are smooth, then it is often a matter of tuning the servo loop.  With a system with a 6K controller and a GV drive, there are many ways of setting it up and that will determine how the system needs to be tuned.

  1. The most common is Torque mode, where the tuning happens all in the 6K and the 6K outputs an analog +/-10V.  That signal goes to the GV drive and is interpreted as +/-100% of peak torque(current) for the motor.

  2. The next most common, is Step/Direction mode, where the tuning happens in the GV drive.  In this case, the 6K output through digital signals a step pulse train and a direction signal.

To figure out what mode the system is in you can query the 6K and the AXSDEF(0 is Step/Dir and 1 is Torque) or the GV with the DMODE command (DMODE2 is Torque and DMODE6 or 7 is Step/Dir)  See guides linked below for more information on those commands.

  1. 6K Command Reference https://www.parkermotion.com/manuals/6k/6K_Command_Reference.pdf

  2. GV Programmers Guide https://www.parkermotion.com/manuals/gemini/Gemini_manuals.htm#Gempr

Most likely tuning the system will improve the performance.

For 6K Torque Mode Tuning

For GV Step/Direction (Position Mode) Tuning