Spindle load - my spindle is driven by a brushed DC motor. I stuck an ammeter in the circuit.
Normally it shows < 0.5 A. I was drilling titanium one day a bit too fast, and the ammeter got up to about 6 A. Oops! Change of Feed rate.
An AC ammeter on the input to the VFD?

Cheers
Roger

Many VFDs can output an analog signal that tells you the current or other interesting things. All you have to do is read it. If you are using Modbus then I believe it can be read that way too.
One of my projects it to read the spindle current and servo load using my analog inputs on my DSPMC.
Could probably be done on an Arduino and then sent into Mach via Modbus. IIRC Mach 4 allows for more than one slave.

My main point is that you don't have to send the info back to Mach. You can stick it on an analog panel meter as a totally passive display, somewhere out front. I find that works just fine.

Cheers
Roger

My Bosch VFD has an extension kit that allows you to mount the VFD display on a panel elsewhere.

My main point is that you don't have to send the info back to Mach. You can stick it on an analog panel meter as a totally passive display, somewhere out front. I find that works just fine.

Cheers
Roger

Hi Roger,
My main point is that you can and have it display on the Computer screen, no need for a separate display.
You can even tie it to the feed override and if the spindle load gets too high you can slow the feedrate to compensate.

Both ways of doing it have their place.

Mike

That would be neat.