Centroid Community CNC Support Forum

tblough wrote: ↑Wed May 15, 2024 10:59 am After all best practices have been employed (twisted pair shielded wire, proper grounds, bypass caps, etc.), you might want to look into a signal isolator:

https://www.amazon.com/Isolator-Insulat ... B09TJTCDQ8

This looks promising...

I was thinking of having an Arduino remap the analog output to RS232 but if this works its a lot easier...

Ok...so what are the practical effects ? Are you attempting to hit a specific RPM and are unable to do so ? Have you solved the overvoltage alarm when coasting down from above 3000 rpm while using the acorn ?

SpacedmanSpiff wrote: ↑Wed May 15, 2024 12:05 pm Ok...so what are the practical effects ? Are you attempting to hit a specific RPM and are unable to do so ? Have you solved the overvoltage alarm when coasting down from above 3000 rpm while using the acorn ?

Yes, i am unable to hit the proper RPM, 10-20% off. I have never had any overvoltage alarms, going from full speed to slow many times during testing, never an issue.

I'm not well versed in centroid. But does not have some kind of compensation so you can just calibrate whatever offset or error out?

Span and slope adjustments are normally in the VFD.

I'm not well versed in centroid. But does not have some kind of compensation so you can just calibrate whatever offset or error out?

Not built in, but you could make your own if you really wanted to.

That would work only if the response is repeatable and linear.

Search your PLC program source for "TwelveBit" to find the calculations that turn requested RPM into a 0-4095 value (which corresponds to 0% - 100% output request). You could add an offset term and a gain multiplier there, if you wanted.

Yes, i am unable to hit the proper RPM, 10-20% off. I have never had any overvoltage alarms, going from full speed to slow many times during testing, never an issue.

Glad to hear that the stop fault is not an issue. Are your speeds repeatable ?

SpacedmanSpiff wrote: ↑Thu May 16, 2024 2:34 pm Glad to hear that the stop fault is not an issue. Are your speeds repeatable ?

They seem to be. But there is some weirdness with the encoder now, it jumps from + to - without me changing anything.

tblough wrote: ↑Wed May 15, 2024 10:59 am After all best practices have been employed (twisted pair shielded wire, proper grounds, bypass caps, etc.), you might want to look into a signal isolator:

https://www.amazon.com/Isolator-Insulat ... B09TJTCDQ8

This product did not work. It requires 24V input, says on the sticker but not the listing. Hooked it up and no bueno. Also tried a second product which was a dud as well. Running out of ideas.

For the spindle a KBSI-240D will do the job.

https://acim.nidec.com/drives/kbelectro ... x?la=fr-fr

Uwe