Controller sending incorrect 0-5V speed signal

I have a Chinese spindle/VFD installed and started having trouble with poor cutting results. I scratched my head for an hour or so and then saw that the input voltage to the VFD is pegged at 5V from 1000rpm onwards.
I have no clue as to why this has happened. I haven’t changed or even so much as moved anything on the router/spindle/VFD except for changing tools.

I am now seeing 0 - 1000rpm as the full range of PWM signal so if I send M3 S500 for example, that gives 2.5V to the VFD.

Has anyone experienced anything similar?
Any ideas on what it could be?

CMotion version is 521

The controller probably has been set so that the maximum speed is 1000. This is common on low end CNC machines, as there is no way to actually set the speed, it’s all just proportional power, i.e. 1000 is ‘full speed’.

If you want to change the range that the controller operates on, you can set the $30 value to the maximum speed.

I probably should have clarified that it was working fine since I installed it last year.
This just started today

I just checked my settings and you’re correct. How this changed to 1000 from 24000 is baffling. Like I said, it was fine yesterday and today it had changed.

Anyway, solved now and tks

Did you recently update CM?

I have to look into my settings because I noticed I was pegged at 24k rpm on my VFD - I was supposed to be at 18k during my most recent surfacing. I recently updated CM.

I didn’t Brian. That’s what was confusing me for a while. I had not done anything to the software. I hadn’t even used MDI for months. All my gcode comes directly from Fusion and was working fine until this morning.
I know it was fine because I’ve been cutting acrylic, mdf and aluminium which all require different F&S.

Very strange.

1000 is the value in the default Shapeoko configuration that gets sent/programmed into the controller when one uses the “Send Configuration Data” button from the Settings menu. Any chance you might have inadvertently clicked that in CM ?

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I think I may have clicked that when I installed the latest CM.

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