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manual feedrate override pot
« on: November 10, 2008, 04:56:44 AM »
Hi all
I am new to this forum and would like some help with fitting feed override (pots) to my Wabeco mill and lathe.
I dont like the mouse one on the monitor and prefer a manual one.

Pick your brains please

Dave

Offline Hood

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Re: manual feedrate override pot
« Reply #1 on: November 10, 2008, 05:07:11 AM »
You can do it a few ways but for a Pot you will need analogue inputs to the computer. Several ways you can get that, PLCs over ModBUS, Peter Homann does a ModIO board that has analogue and also there is the PoKeys that has analogue (not sure if they are working well enough yet)
 Another way to do it is have two or three momentary switches, one for Up,one for down and the other for reset, you can then make up a brain that steps up or down through the speeds when you keep the button pressed.
 Lastly you can get a rotary switch and make up a Brain to set the feedrate to a different amount depending on the position of the switch.
The analogue/pot option is probably the best but the rotary switch comes a close second and is obviously a lot cheaper.

Hood
« Last Edit: November 10, 2008, 05:10:48 AM by Hood »
Re: manual feedrate override pot
« Reply #2 on: November 10, 2008, 05:58:38 AM »
Well Hood your brain is certainly active
Thanks for the instant reply & remedy
Dave

Offline Hood

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Re: manual feedrate override pot
« Reply #3 on: November 10, 2008, 06:08:16 AM »
Well Hood your brain is certainly active
Thanks for the instant reply & remedy
Dave

No chance, its not been active for a long time, if ever ;D

Hood
Re: manual feedrate override pot
« Reply #4 on: November 10, 2008, 07:41:10 AM »
Hey hood, (I hope to get this in while there are still signs of activity) he he

With the 3 momentary switches, I assume I would need 3 input pins. ? ? ?

With the rotary switch, would I need 1 input pin for each position ? Not sure.

Thanks,
RC

Offline Hood

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Re: manual feedrate override pot
« Reply #5 on: November 10, 2008, 08:10:12 AM »
Well there is never much activity with me whether brain or otherwise :)

Yes thats correct on both counts.
It might be good to get a pokeys for something like this as even if the analogue isnt good enough then you could use it with a rotary switch as you have 55 digital I/O on it so plenty there :) I have tried that and it works well but not tried the analogues on the pokeys yet.
 The most economical as far as I/O is concerned is PLC or ModIO using analogue input but obviously a bit more expensive.

Hood
Re: manual feedrate override pot
« Reply #6 on: November 10, 2008, 10:28:06 AM »
Been on to Peter Homann's site and looks like what I need
Excuse my ignorance but will it work in cnc mode or only manual
I have zero electronic knowlege so put up with me for a while
Im just north of you in Aberdeenshire (Newburgh)

Dave
Re: manual feedrate override pot
« Reply #7 on: November 10, 2008, 11:00:34 AM »
Hey hood, (I hope to get this in while there are still signs of activity) he he

With the 3 momentary switches, I assume I would need 3 input pins. ? ? ?

With the rotary switch, would I need 1 input pin for each position ? Not sure.

Thanks,
RC

You can reduce the number of input pins required by using a rotary switch with binary or BCD coding.  That would allow, for instance, a 16-position switch to use only 4 input pins.   You'd then create a brain with 16 "lobes".  Each "lobe" of the "brain" would have to look at all four values to determine the switch position.

Regards,
Ray L.
Regards,
Ray L.

Offline Hood

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Re: manual feedrate override pot
« Reply #8 on: November 10, 2008, 11:31:27 AM »
Been on to Peter Homann's site and looks like what I need
Excuse my ignorance but will it work in cnc mode or only manual
I have zero electronic knowlege so put up with me for a while
Im just north of you in Aberdeenshire (Newburgh)

Dave

Good to have another Scot here :)

Yes this will work as you are machining just like the on screen one does.



You can reduce the number of input pins required by using a rotary switch with binary or BCD coding.  That would allow, for instance, a 16-position switch to use only 4 input pins.   You'd then create a brain with 16 "lobes".  Each "lobe" of the "brain" would have to look at all four values to determine the switch position.

Regards,
Ray L.

Yes Ray that would work great, never actually thought of that but dont know why as thats the way my servo drives can work if in indexing mode, 63 index positions from 6 inputs.

Hood

Re: manual feedrate override pot
« Reply #9 on: November 10, 2008, 11:37:05 AM »
Hood,

    Actually, you could do it with a normal selector switch as well, using diode logic, or a few logic gates.

Regards,
Ray L.
Regards,
Ray L.