Spindle speed incorrect Mach3

[kvom]

I just received one of those inexpensive laser tachometers and used it to check the actual NM200 spindle speed vs. the Mach3 command. The speeds are off a good bit, as I knew going in. At this time, a mach3 speed of 500 reads over 1200 on the tach, and each increase of 100 RPM in mach3 increases the spindle speed by 270 rpm. The VFD display shows numbers close to the tach, and I have been adjusting the mach3 speed in the past so that the VFD shows the speed I want.

Does anyone with a series 1 NM200 have correct speeds via mach3, and if so will you share your XML, or a screenshot of the spindle motor setup screen.

[cteufert]

I don't have a NM200 but I do have a NM145 with similar speed issues.

I have played around with the VBScripts in Mach3 and found the one that sets spindle speed. As is it requests the speed the user wants and outputs it to the machine. I was able to make a minor change to bring my speeds more in line by inserting a line between the two that are there:

RPM = RPM * 0.8

My speeds are rough guesses since my tach stopped working 1/2 way thru testing and I haven't replaced it yet. Based on your numbers I suggest the following:

RPM = RPM * 100 / 270
or
RPM = RPM * 0.37

Charlie.

[kvom]

I'll try that, thanks

[kvom]

The VBScript worked for me. Thanks!

Something to be aware of is that this translates the S code, but it's the translated code that shows up in the spindle speed DRO. So if I put 1000 in the DRO and start the spindle via the button, the spindle will be turning at 2680 (my ratio in the script is 2.68). Similarly, M3S1000 will turn the spindle at 1000 but display 373 in the DRO.

[cteufert]

Glad to hear the tip to modify the VBScript worked out for you. There is most likely a way to muck around in the Mach3 screen set to change the scale of the DRO but I haven't looked in to that area as of yet.

I was able to get the spindle speeds to be more accurate on my NM-145 with a different change. Instead of highjacking this thread I will start another.

Charlie.

The VBScript worked for me. Thanks!

Something to be aware of is that this translates the S code, but it's the translated code that shows up in the spindle speed DRO. So if I put 1000 in the DRO and start the spindle via the button, the spindle will be turning at 2680 (my ratio in the script is 2.68). Similarly, M3S1000 will turn the spindle at 1000 but display 373 in the DRO.

[kvom]

The DRO issue isn't a biggie, as I normally will just enter 400 for edgefinder use; otherwise the g-code will control the spindle.

[bob b]

my spindle does not even come close i have to run mine 600 to get 300 i do not understand why this was not set when they checked out machine

[kvom]

my spindle does not even come close i have to run mine 600 to get 300 i do not understand why this was not set when they checked out machine

It would be nice to understand how the VFD/Motor are controlled. Is it the step/dir pulse times? Some VFDs use a 0-10 control voltage range. Some documentation on how to tune mach3 for the spindle motor ought to be provided.

In the meantime the VBScript solution is working for me.