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Oak physical feed rate and spindle speed override knobs.

Posted: Wed Feb 17, 2021 10:31 pm
by Jqmce
Hello guys,
Have just purchased the oak board with 1616 IO and wireless Mpg.
Converting an Atrump E216 mill w 16 tool ATC that has the very strange ITRI M2000 control.

I would like to add two physical rotary knobs to control feed rate override and spindle speed override. I understand this is available on the MPG and touch HMI but old habits die hard and would love two panel mounted knobs.

I believe this can be done with the addition of the optional analog input output board but I have all ready blown the budget and don’t feel like spending another 500 clams.

Is there any other way I can do this? At the least would like feed override if I can only do one.

Have been thinking about getting creative with an Xkey controller with rotary knob or something like that but would prefer hard wired to Oak solution.

Thanks for your thoughts on the matter.

Cheers
Jules

Re: Oak physical feed rate and spindle speed override knobs.

Posted: Thu Feb 18, 2021 2:30 am
by cncsnw
I would make do with the VCP controls until I earned enough money to buy a Centroid control pendant (pn11077).

It has the feedrate override knob built in.

Barring that, your best bet is some sort of pulse generator / low-resolution encoder that you can wire to a couple PLC inputs and read quadrature-style.

Re: Oak physical feed rate and spindle speed override knobs.

Posted: Thu Feb 18, 2021 9:42 am
by Jqmce
cncsnw wrote: Thu Feb 18, 2021 2:30 am I would make do with the VCP controls until I earned enough money to buy a Centroid control pendant (pn11077).

It has the feedrate override knob built in.

Barring that, your best bet is some sort of pulse generator / low-resolution encoder that you can wire to a couple PLC inputs and read quadrature-style.

Thanks cncsnw
I think the idea of the pulse generator to PLC is interesting. Do you know if anyone has tried this.

Re: Oak physical feed rate and spindle speed override knobs.

Posted: Thu Feb 18, 2021 1:45 pm
by cncsnw
Not that I know of.

You would need an open-collector pulse generator that can operate at whatever DC voltage and polarity you choose to use for the associated PLC inputs.

If you are not familiar with quadrature decode, see http://www.cncsnw.com/Quadrature.htm.

There are eight different transition conditions you can monitor: four that indicate forward movement, and four that indicate reverse movement. Of course, if you don't need the maximum possible resolution from your encoder, you could monitor just some of the conditions: for example, if you only count up or down on a rising edge of channel A, then you only need to watch for two conditions: rising edge of A while B is high, and rising edge of A while B is low.

If you use a rotary encoder, with negligible rotational resistance, then you will want to add some type of friction, damping, or detents to your knob assembly.

Good luck.