Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: CNC4fun on February 27, 2009, 05:22:44 PM
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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
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The way you had it set up first should have worked fine.
Hood
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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.
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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
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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
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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
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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
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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