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Problem with AXBB-E using VFD limit switch triggers

PostPosted: Tue Jan 02, 2024 3:22 pm
by Fehlmann 100
Hello everyone,

i'm new here.We are retrofitting a Fehlmann Picomax 100 CNC mill. I used the AXBB-E motion controller with stepper motors.
it is working fine but when we connect the VFD to the motion controller and control the VFD using 0-10V we are getting what I believe is EMC interference.
When we start the spindle the limit switch is getting triggered and the machine stops. Furthermore we use the potentiometer on the VFD the problem is gone.

https://youtu.be/FWgVu10s26Q

Does someone know how I can fix this?

Thank you in advance

Re: Problem with AXBB-E using VFD limit switch triggers

PostPosted: Wed Jan 03, 2024 9:18 pm
by cncdrive
Try to set the debunce filter time constant in the I/O settings in the UCCNC to filter out the noise spikes in software from the input pins.
Also you can try to install a 100 Ohm or similar value resistor in series with the analog output of the AXBB-E and the analog input of the VFD and put a capacitor between the analog input of the VFD and the analog ground of the VFD. The capacitor can have a few microfarads value.

Re: Problem with AXBB-E using VFD limit switch triggers

PostPosted: Thu Jan 04, 2024 8:13 am
by Fehlmann 100
Thanks cncdrive,

do you mean, input signals debounce (ms):

Thanks

Rink

Re: Problem with AXBB-E using VFD limit switch triggers

PostPosted: Fri Jan 05, 2024 2:57 pm
by cncdrive
Yes.