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Setting up Encoders
« on: February 27, 2009, 05:22:44 PM »
Hi Everyone
I'm trying to set up a machine with Encoders.

I looked for instructional Videos but there nothing specific.

I'm half ways there but stuck:

I Can see the encoder signals in Diagnostics.

I only have ONE LPT port  but I wanted to try and install at least one Encoder

First I tried to just set up under Encoders/MPGs  
Encoder1
Enabled, Channel A to pin13    port 1
Enabled  Channel B to pin 15   p1

Didn't get anywhere with that.


so I also went to INPUTS then in

INPUT#1   Enable,  p1  Ch A to Pin 13
INPUT#2   Enable,  p1  Ch B to Pin 15

So Now I can see the the encoder activity as I turn the shaft in LED lights in Diagnostics.

But I can NOT see How to send those signals to be utilized, COUNTED by mach3 or To Which axis to attach that to

I don't know if I'm supposed to "Share"  to get it to work or if Just created a conflict and nothing will happen even if the LED  Hi/LO states are detected.

I someone can help me with this I can make a Video and Post it here for the instructional Video Archive

Thanks Fellas.

CNC4fun


« Last Edit: February 27, 2009, 05:25:35 PM by CNC4fun »

Offline Hood

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Re: Setting up Encoders
« Reply #1 on: February 27, 2009, 05:38:07 PM »
The way you had it set up first should have worked fine.


Hood

BClemens

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Re: Setting up Encoders
« Reply #2 on: February 27, 2009, 06:21:43 PM »
Are you sending these encoder signals into your computer via a break out board or straight into the parallel port? You should be able to run a four axis machine one parallel port. Usually, the encoder signal is a feedback to the servo drivers so do not go into the parallel port....or did I miss something in your hook-up?

Bill C.
Re: Setting up Encoders
« Reply #3 on: February 28, 2009, 02:20:59 AM »
Hi Bill
Well, normally, if your motor Drive has Encoder inputs that's where it would go.

but I saw on a video here That with a second LPT port  you could turn all your outputs into INPUTS and set up multiple encoders.    but the Vid just touched on the subject.

and you can see that in the  Encoders/MPGs tab in PORTS and Pins

I Can see the signals in Diagnostics
but I don't see   what to do w the signals next. but I guess I'm missing something.  like "Closed loop setup"  settings.

Hood says that the first way I did it, should've worked.    so, I'll try again     something I'm missing ...

Oh, and I am using a breakout board.


CNC4fun

« Last Edit: February 28, 2009, 02:23:39 AM by CNC4fun »
Re: Setting up Encoders
« Reply #4 on: February 28, 2009, 03:03:44 AM »
Ok
I went back and removed the INPUTS settings and left only the Encoders/MPGs settings for Encoder1

I can still see signal activity in "PORT 1 Pins current state"
so the signal are coming in with Encoder1 setup.

but I can not find anything that tells me  where to send these signals or how to get Mach3 to use that as closed-loop SETUP


CNC4fun

Offline Hood

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Re: Setting up Encoders
« Reply #5 on: February 28, 2009, 05:29:34 AM »
Mach is NOT closed loop, the encoder input is for your reference only. You could use it for error checking via a plugin or a macropump if you wrote one.
 With Servos you close the loop at the drives as Bill said.
Hood
Re: Setting up Encoders
« Reply #6 on: March 02, 2009, 02:04:13 AM »
Mach is NOT closed loop, ....
Hood

Really?   somewhere I read that in non-critical applications like routers you can have open loop just fine
But when you have a Lathe or Mill where things are critical and accuracy is needed you have to go with closed loop but it was recommended that feeback should Not exceed 30,000 ppr or the Mach would be overwhelmed  having to deal with Stepper motors  plus encoder feedback,

plus the mach does have setting for several encoders and MPGs
however, preferably, they should be set up on the SECOND LPT port where all the outputs can be set as inputs
since LPTs   ARE bi-directional ports.

Also,  I think Mach can be used with Galil Cards but you have to install the  Galil plugin in

Then the Gallil can accept any kind of motor; stepper, brushed , brushless, etc. and any type of encoder

I'll keep searching.   I just hope that MACH3 makes more videos (short) with specific tasks.


CNC4fun   (not having fun yet)  ;D

Offline Hood

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Re: Setting up Encoders
« Reply #7 on: March 02, 2009, 02:25:09 AM »
Nope, Mach is Open loop, if you have steppers and have them sized and tuned correctly then you will have an accurate machine. If you have servos then the servo drive closes the loop.
  You can use encoder feedback to halt Mach if if it exceeds a specified error between encoder position and where it thinks it should be, this would require you writing a macropump or you could get the encoder interface from rogersmachine.net, neither however will correct on the fly so it is not closed loop in the true sense.
 Hood