AXBBe 0-10v pwm fluctuation

[CNCChris]

I am guessing I am having a noise problem. The output of the 0 to 10 volts of the axbb-e controller is fluctuating. I can't seem to figure out whats going on , I have tested the input from the 5 volt and 24 volt power supplies and there is 0 fluctuations in voltage. It's enough of a fluctuation that the voltage affects the spindle output with a variance of about 500 to 800 RPM.

I've put a multi meter on AO1 and 5v0 and you can see the voltage go up and down, how would one find out what's going on.

The controller is in a different enclosure from the VFD, about 3m apart.

[cncdrive]

If you unconnect the analog output and measuring on the A01 and 5V0 then the voltage is still fluctating?

[CNCChris]

When removing the cable from the axbbe that runs to the VFD there is zero fluctuation and the voltages are spot on.

I have the shield grounded at the controller side, is this ok or should it be ground at VFD side instead?

What do I do to make signal stable when wired in? Add a 100uf on axbbe and VFD?

Thanks

[cncdrive]

It looks like then that the VFD analog input circuit makes the signal to fluctate.
Yes, you can try to add some buffering to the signal.
Add a 100uF capacitor to between the signal and it's ground at the VFD side.
Also you can add a small ceramic capacitor in parallel, a few 100nF to filter high frequency noise.

[thegreatwaldo]

Would the + leg of the 100mf cap connect to the signal side or is the polarization of the capacitor irelavent if it's an electolytic ?
Thanks
Andrew

[cncdrive]

nop mF, but uF, m is milli and u is micro, milli is 1000 times larger.

For electrolit caps the polarity is important, for ceramics it is not.