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

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

• This link is for the 6K Programmer's Guide and on PDF Page 79 (pg 67 of the document) is the procedure to tune the system.  6K_Programmers_Guide_with_Covers.doc (parkermotion.com)

• Here is the link to the Motion Planner software if you need it.  Note this software will only run on Win XP or 7.   https://divapps.parker.com/divapps/emn/download/6K/MotionPlanner_4p3p2.exe

For GV Step/Direction (Position Mode) Tuning

• This is the link to the GV Hardware Installation Guide and on Page 28 is the section on tuning.  Look for the Position Mode section.  Gemini GV Hardware Installation Guide (parker.com)

• You will use the same Motion Planner software linked above.