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Author Topic: Need Extra Inputs  (Read 7613 times)

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Offline Katoh

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Need Extra Inputs
« on: October 02, 2011, 09:07:44 AM »
Colleagues
I am getting close to finally putting this lathe together, stand is built and the electrical boxes are in, now its the main wiring and then just the placement of the lathe on the stand. As I accumulated parts for this retrofit, I was given a very nice little panel that came of a commercial machine. This panel has a light switch an e-stop and 4 push buttons on it for jogging the the two accesses. I would really like to incorporate it into the build.
The problem I see is I dont have enough input pins, I'm using just the one parallel port and a Homman BOB. The way I see it I would need  Spindle feedback (1) Limits & E-stop can be put into one (2) Jog Z+(3) Jog Z-(4) Jog Y+(5) Jog Y-(6) , so there is 6 input pins needed.
How can I do this without adding another BOB or going to USB?
Also incorporated in the build is a 3rd motor driver for future use as either an X axis or Turret control.
Thanks
Katoh
Cheers
Katoh

Offline Hood

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Re: Need Extra Inputs
« Reply #1 on: October 02, 2011, 10:06:27 AM »
Not much you can do except add a second port or some other type of I/O such as ModBus, USB etc. There is the PMDX 126 Bob that can use 1 port but double up on the i/o but that obviously means expense. You could just use a PCI port without a BOB  if you were confident about your wiring.

Hood

Offline Katoh

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Re: Need Extra Inputs
« Reply #2 on: October 02, 2011, 10:28:42 AM »
Hi Hood
I'm coming to the same conclusion. A standard board has 5 inputs and need 6. The only thing that crossed my mind is if I daisy chain the e-stop and the limits and instead of inputting them into the BOB, I could use them on a relay that control's the 5v power to the the BOB. If triggered the power will be cut and the lathe should stop, but will Mach recognise this as a fault and estop the program?
Could be a thought.
Cheers
Katoh
Cheers
Katoh

Offline Hood

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Re: Need Extra Inputs
« Reply #3 on: October 02, 2011, 10:48:14 AM »
Ah sorry I was thinking you were needing a further 6 inputs. Still doesnt change things much. Cutting the 5v to the BOB may work but Mach will not know about it unless you have an input informing Mach.

Oh BTW the axis on a lathe are Z and X.

Hood

Offline Katoh

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Re: Need Extra Inputs
« Reply #4 on: October 02, 2011, 10:55:54 AM »
Quote
Oh BTW the axis on a lathe are Z and X.
Apologies mind was elsewhere when typing.
Looks like a second port is the only quick and correct solution. If i g down that track is there a way to control jog speed with say a potentiometer, or some other sort manual control on the panel?
I am very confident of wiring so a BOB will not be necessary, I think.
Cheers
Katoh
Cheers
Katoh

Offline Hood

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Re: Need Extra Inputs
« Reply #5 on: October 02, 2011, 11:03:39 AM »
You need analogue inputs to use a pot for such things as Feed Override or Spindle Override. May be worth your while looking at the PoKeys, bit of an expense but will give you the analogue inputs as well as a load of other I/O capability.
Hood

Offline Katoh

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Re: Need Extra Inputs
« Reply #6 on: October 02, 2011, 11:15:06 AM »
The Funny thing is I was looking at looking at that but was not certain exactly what it did. I cant see 50 odd euro as too expensive if its going to do what I want. I will have another look into them and send the seller an email with some question, may enlighten me on the subject a lot. If its good I could have all sorts buttons, Start, home, ect maybe a good thing.
Many Thanks Hood.
Cheers
Katoh
Cheers
Katoh

Offline Hood

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Re: Need Extra Inputs
« Reply #7 on: October 02, 2011, 11:49:01 AM »
The PoKeys gives you 55 low voltage I/O which you can define as you wish (either Inputs or Outputs) You can also use 3 (I think, been a while) of them as analogue inputs and you can also use some of them for MPG inputs if you wish. The MPG inputs didnt work that great when I first tried the PoKeys a few years back  but I believe now they work very well.
My preference would probably be for the Ethernet version over the USB one but the USB did work well when I tested it out.
Hood

Offline Katoh

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Re: Need Extra Inputs
« Reply #8 on: October 04, 2011, 07:35:41 AM »
Hood
I have inquired and really for my needs I'm better of going down the 2nd Port option, far less complex than the other.
Can you input a MPG with the second port? if so how would you do it?
Cheers
Katoh
Cheers
Katoh

Offline Hood

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Re: Need Extra Inputs
« Reply #9 on: October 04, 2011, 08:39:55 AM »
Pokeys is or at least at the time I used it very simple but to answer your question, yes MPG is no probs, just tell Mach which pins and port the A and B pulses are on.
When I was using the parallel port on the Bridgeport I had a second port with the MPG on it, I powered the MPG from a cut down USB cable and just input direct to the port without a breakout board, worked fine.

Hood