Analog PWM's at 20%

4minnovations · Post by **4minnovations** » Mon May 03, 2021 12:07 pm

Hi Tom,
I have a problem with the axis #3 (machine with 4 axis, all connected to a snapAmp).

As soon as I put axis 2 or 3 to enable( without charge in the axis), I can see in the "Analog status" window, a consumption in% PWM of 20% for axis 3 and also 10-15% for axis 2.

If I disconnect the motor from axis 3 and put axis 2 to enable, everything is at 0% in the pwm of the "analog status" window.

If I connect the motor and encoder from axis 1 (no problem) to axis 3, and I put axis 3 to enable, I still get a consumption in% PWM of 20% for axis 3 and also 10-15% for axis 2 in the "Analog status" window.

The problem is that axis 3 triggers an error and goes to disable and stops the machine frequently.

Over the weekend, I reduced the speed and acceleration of axis 3, and it seems to be working for now.

Do you think it's a hardware problem with the snapamp?

Post by **TomKerekes** » Mon May 03, 2021 8:17 pm

Hi,

It would be strange for an axis to be command a PWM % without being enabled is that what you are saying?

Please post your Initialization C Program.

4minnovations · Post by **4minnovations** » Tue May 04, 2021 11:31 am

Hi,
I am not 100% sure that axis 2 was enabled.

On the other hand, I am sure that if axis 2 is to enable and axis 3 to disable, I have 0% PWM for all my axes. I set axis 3 to enable, immediately there is a 10% PWM appearing on axis 2 and a 20% on axis 3.

Post by **TomKerekes** » Tue May 04, 2021 1:44 pm

I’d need to know your exact configuration of all axes, exactly what you are doing and what happens.

Possibly more than one axis configured to drive a pwm? Or configured incorrectly? Or possibly some wiring issue? Or bad SnapAmp.

4minnovations · Post by **4minnovations** » Tue May 04, 2021 4:02 pm

Hi Tom,

I have placed the axis initialization file as an attachment.

After initialization the axes are set to enable and I get the PWM% discussed with no movement requested.

Post by **TomKerekes** » Wed May 05, 2021 2:56 pm

I don't see any issue with the configuration.

One test would be to enables axis 3 with axis 2 disabled (or vice versa) and see if axis 2 shows some non zero PWM as you seemed to indicate earlier. That could not be explained by bad hardware.

4minnovations · Post by **4minnovations** » Fri May 07, 2021 4:59 pm

Hi Tom,
We replaced the snapamp this morning.

We wanted to do some tests and send you the results, but the machine had been shut down for several hours and the problem was not present this morning.

We suspect a cold junction problem, linked to the heating of the board.

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Analog PWM's at 20%

Analog PWM's at 20%

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