All I want is for the machine's rpm to match commanded and actual. I.e. When I command m3 s1800 and measure the actual rpm using a tachometer it matches pretty close, not off by a few hundred rpm.

I understand your frustration but it is not a Mach4 problem and it is not an ESS problem.

The problem lies in whatever connects the PWM output from your ESS to your spindle motor and these are perhaps the areas in which you should be testing.

1) Is the analogue voltage output from your C32 BoB (0 to 10 Volts) linear to the Mach4 commanded S#### ??

2) Does your VFD have linear response (output frequency) when driven by a regulated 0 to 10 Volt standard ??

Tweakie.

If it is not a mach4 problem then why when I change the pulley settings, does it affect the actual rpm?

If it is not a mach4 problem then why when I change the pulley settings, does it affect the actual rpm?

I have no answer for that other than what it says in the manual…

"The Spindle dialog allows the configuration and setup of up to 20 spindle rages. The spindle ranges can be gears and or belt settings to allow for a change in the range of speeds available. The reason for the maximum RPM is to allow for proper scaling of the motors RPM on all ranges. The motor RPM is used by motion devices, plugins, VFD's, Lua etc for planning the proper motor RPM to get the requested spindle RPM”.

Whilst the range and the scale can be set, it is my understanding that the problem you are experiencing is one of linearity.

Tweakie.

correct Tweakie there was a post last year someone worked out what the scale is and he got it bang on with some fancy numbers, Darwin had or has the same thing with spindle speed control I had to have some big numbers to get the correct speeds

This topic has now moved http://www.machsupport.com/forum/index.php/topic,32174.0.html

Tweakie.