Tangential Cutter C/A - Following Error/Tuning

Hi Friends, 

The goal is a tangential knife setup with a pizza type cutter blade. To achieve this i have a servo driving a pulley that drives an output shaft with the  blade on it. my goal right now is to get it to jog without errors. 

In Axis, when i jog the A axis its slow and jittery. I increased the speed to about 500 deg/min and it moves faster but just as jittery. Anything over 600 i get a following error, I also get random following errors throughout normal jogging. I checked all the connections and they seem fine. Which leaves makes me think it might be the servo tuning. 

I tried to follow this guide to tune it ( gnipsel.com/linuxcnc-old/tuning/servo.html ) however, i cannot find the signal in hal scope. The tutorial calls out 'axis.x.f-error' i can only find 'joint.x.f-error' and get no change when i trigger it with a movement. what is the difference between these two and am I on the right track?

Any advice is greatly appreciated. 






 

forum.linuxcnc.org/10-advanced-configura...to-example-mesa-7i77

Thank you ill dive into this now, not sure how I hadn't found this before. Cheers.

I seem to have different pins than listed in the tutorial you linked. I've attached a screenshot below of the pins that i have available to  me. This was sort of the same issue i was having with the guide i found and was trying to follow. any idea where i can find these pins and start turning??

How is the servo drive driven?
Is there feedback to LinuxCNC from the drive?

Can you post your current hal/ini files?

I hope that i am understanding what your asking correctly. The motor is driven by a CL driver from stepper online. I have the motor wired to the stepgen 3 on the board  7i96 and the encoder to the encoder area on the board. Data sheet attached.

my assumption is that there is feed back from the encoder i just can't seem to find our what channels to listen to so i can tune it in. 

 

Hi Friends,

Sorry i probably elaborate enough. My goal is to reduce the error in my C/A axis. Currently it jogs, but its shaky and based on what i've seen tuning the servo could help this.

I am reasonably confident in my step and encoder scale figures - 90 deg turn looks like a 90 deg turn. The main issue i am having is that i can't for the life of me find any of the encoder pins that i should be using to tune in HalScope. I know that the tutorial is for a different board but i imagine they would have similar names? i am using 7i96s, below is a screen shot of halwatch when i search for the work "analog". Most of the highlighted ones seem to be inputs, e.g. when i put them in the scope i can enter a value for them. the only ones that seemed to be outputs are in the photo and do no change when i jog the C axis

any advice is greatly appreciated