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Author Topic: Mach w/ digital scales or encoders for DRO until full CNC conversion  (Read 13231 times)

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I've looked at the mach3 doc. and haven't been able to tell if mach will use a digital scale input for manual oper. DRO or If this is even possible w/ encoders.
I would like to get a dro for now and cnc later but would hate to get something I can't use later on.
My thoughts are to use Mach3 as a DRO w either a digital scale or encoder for possision, And later use these for feed back for CNC .Does this sound possible??

Thanks Hans

Offline Hood

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #1 on: December 19, 2007, 04:15:04 PM »
I had glass scales hooked up through Rons encoder Interface board you could use them in manual mode with Mach to act as a DRO.
I am not sure if you just hooked up through the PP as normal whether it would work the same or not, but it may well do.
Hood
Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #2 on: December 19, 2007, 04:23:30 PM »
Yeah I'm thinking that I should just start experimenting as I really can't find anything in the document other than hooking up encoders for feed back. I seem as thou that should work.

Hans

Offline jimpinder

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #3 on: December 20, 2007, 04:20:00 AM »
The DRO's on Mach3 do not normally take information from your lathe/mill. The DRO's are run by the computer, according to the number of pulses it puts out to the stepper motors. In other words the DRO's show where Mach3 THINKS the machine is.

It is normally very accurate (at least it is on my machine), unless there is some problem and the motors start missing steps.

I do not use any digital scales or encoders on my machine and rely on Mach3 DRO's to be accurate.

I would have thought that the first thing to do is get your machine to respond to Mach 3 - i.e. get some stepper motors on the axis. I cannot see that this would cost much more than a digital scale or readout (unless you already have them).

Once you have your machine controlled by Mach3, you can still use it "manually" by using the "jog" facility or programming each line seperately.
Not me driving the engine - I'm better looking.

Offline Hood

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #4 on: December 20, 2007, 11:32:21 AM »
Not strictly true Jim, the Encoder DROs on the settings page should respond to input from encoders or glass scales as long as you have them set up in the Encoders Inputs.
Hood
Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #5 on: December 20, 2007, 11:05:29 PM »
So Mach can use the encoder input that is usually used for servo feedback to give you a DRO. It seemed as such in the doc's but thank's for the verification.

Hans :)

Offline Hood

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #6 on: December 21, 2007, 02:57:05 AM »
Depends what you are meaning by "usually used for servo feedback" Mach doesnt take the feedback from a servo system, the feedback goes to the drives. However if you are meaning can you hook up encoders to Inputs then yes you can. you will see them in the Encoder DRO's but they will not be used by Mach for any type of closed loop system. What you are wanting to do should work OK as you are only wanting a readout.
Hood

Offline jimpinder

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #7 on: December 21, 2007, 10:45:57 AM »
Hood - My apologies

Jim
Not me driving the engine - I'm better looking.

Offline Hood

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #8 on: December 21, 2007, 11:17:40 AM »
No apology needed Jim. I am not 100% certain that it works the way I mentioned as I havent actually done it but what I have done is use Rons encoder interface with glass scales and that worked. However the purpose of the interface wasnt to just hook up encoders it was to provide a sort of closed loop. As far as I can recall the encoders (glass scales in my case) just went through this interface board to the parallel port so that makes me 99.99% sure you can hook up directly to a port and it will work. In fact I think I will just go and rig something up to make sure I am not spouting a load of rubbish :)

Hood
« Last Edit: December 21, 2007, 11:22:39 AM by Hood »

Offline Hood

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Re: Mach w/ digital scales or encoders for DRO until full CNC conversion
« Reply #9 on: December 21, 2007, 12:56:43 PM »
OK it took a while as I had to make up a parallel port cable and then search the net for the pinouts of the encoder. Anyway I hooked the encoder up to 5V and ground of the computer and had the A and B channels of the encoder on pins 11 and 12 and set it up as encoder 1. When rotated the X  Encoder DRO shows the position, so now I am 100% sure :)

Hood