AXBB-E not decreasing PWM voltage

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AXBB-E not decreasing PWM voltage

Postby Stock3000gt » Sun Jan 19, 2020 11:16 am

I am at a loss I have been over the settings in UCCNC but I can't seem to get the PWM voltage to operate correctly. No matter what I set the spindle speed to it only sends 9.8v which seems to be my top voltage as that's what the voltage is coming out of the AXBB-E. Any guidance would be appreciated.

My settings are as follows.
Spindle page
PWM Freq-1000
PWM min duty- 0
PWM Max-100
M3 relay pin 2 port 1
spindle velocity min-18000
spindle velocity max- 24000
both pwn spindle and spindle relay output enabled are checked.
I/O setup page
only thing I have done is Spindle PWM -> analog ch. 1
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Re: AXBB-E not decreasing PWM voltage

Postby dzone » Thu Feb 20, 2020 5:55 pm

I wanted to write the same things today, but something I didn't expect has happened.
Before writing, I also tried UCCNC version 1.2113.
I set it all up from scratch. I ran the spindle and adjusted the speed I wanted from the control panel.
To my surprise, everything was as it should be.
Up-down desired speed can be adjusted.
While it thought I had solved the problem with the new version, it stopped working again.
(I run it, AXBB is sending 9.8V and Spindle was running at 18000 rpm)
I undoed my change and the spindle started working normally.

All I did was uncheking the Enable PID option under Spindle PID Control.

By the way, my VFD Siemens Sinamic V20 3kw version.

AXBB - VFD
AO1 -> AI1
5V0 -> 0V
O2 -> DI1
24V0 -> 0V (24v)
DIC <--> 24V in VFD will be bridged.

Maybe it will be useful to someone.
Attachments
enablepid.jpg
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Re: AXBB-E not decreasing PWM voltage

Postby cncdrive » Thu Feb 20, 2020 7:10 pm

The PID control takes over the spindle control and so the analog output if the function is enabled. It requires an encoder to control the motor with the encoder measuring the spindle motor rotational speed.
So, unless if your spindle motor has an encoder and is connected back to the motion controller and is configured as spindle encoder then that will make the analog spindle output as well as the spindle PWM to go to 0V or 10V no matter what spindle speed you program, because then there is no feedback without a properly configured encoder on the spindle, so the PID loop will saturate the output.
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Re: AXBB-E not decreasing PWM voltage

Postby dezsoe » Thu Feb 20, 2020 10:42 pm

Thank you, dzone!

Stock3000gt has the same problem. I've just checked his profile and spindle PID is turned on.
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Re: AXBB-E not decreasing PWM voltage

Postby dzone » Fri Feb 21, 2020 8:40 am

cncdrive wrote:The PID control takes over the spindle control and so the analog output if the function is enabled. It requires an encoder to control the motor with the encoder measuring the spindle motor rotational speed.
So, unless if your spindle motor has an encoder and is connected back to the motion controller and is configured as spindle encoder then that will make the analog spindle output as well as the spindle PWM to go to 0V or 10V no matter what spindle speed you program, because then there is no feedback without a properly configured encoder on the spindle, so the PID loop will saturate the output.

learned something again,
my vfd can work with pid control. Actually, I can try that too.
Extra wire connection may be required and i have no idea about it.
Sinamics V20 Manual (Page 72)
Regarding the subject, I think that a setting like this, could solve more "AXBB VFD speed adjustment problem".
Attachments
enablepid.jpg
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