Does this pin assignment look OK?

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01 Dec 2011 14:26 #15252 by Harry_Y
Does this pin assignment look OK?

(Bold = Lathe only, Plain = Mill only, Italics = Both Lathe and Mill)

Pin Dir Function
1 Out Lathe X Step
2 Out Mill X Step
3 Out Mill X Dir
4 Out Mill Y Step
5 Out Mill Y Dir
6 Out Mill Z Step
7 Out Mill Z Dir
8 Out Mill A Step
9 Out Mill A Dir
14 Out Lathe X Dir
16 Out Lathe Z Step
17 Out Lathe Z Dir

10 In E-Stop
11 In Limits

12 In Lathe RPM
13 In Mill RPM
15 In Mill Tool Height


My thoughts are to build two configurations with only the pins active for the current
machine in use the ones not associated with that machine will be set to unused.

This way all I need to do is to turn the associated driver on and load the proper configuration.

Note: I am assuming I can read RPM with a single pulse using something like a optical or hall effect sensor

Later I may add a Mesa card, but for now this should get me up and running for now.


Thank you

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01 Dec 2011 15:03 #15255 by BigJohnT
Well to get you up and running you only need the outputs for step and direction. If your going to share all the limit switches into one input make sure both the I assume you will have the signal power on for both and connect all normally closed switches in series so if any switch is tripped then the input reads it and similar for the E-Stop as well as the E-Stop breaking the power to the drives physically.

Are you just wanting to make a RPM meter for your pyvcp panel and not thinking about threading with a single pulse?

Tool Height = Probe Input?

John

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01 Dec 2011 16:31 #15260 by Harry_Y
BigJohnT wrote:

Well to get you up and running you only need the outputs for step and direction. If your going to share all the limit switches into one input make sure both the I assume you will have the signal power on for both and connect all normally closed switches in series so if any switch is tripped then the input reads it and similar for the E-Stop as well as the E-Stop breaking the power to the drives physically.

Are you just wanting to make a RPM meter for your pyvcp panel and not thinking about threading with a single pulse?

Tool Height = Probe Input?

John


Yes all the limit switches will be in series for both machines, since
I will only use one at a time that should be OK for my small setup

The RPM meters for now will be strictly for RPM
(more of a convenience than anything else at this point)

I will need to add inputs later so I can do threading, I would
assume i will also need to add a quadrature encoder for that.
(I am new to CNC threading)

The tool height will be a probe input, I do that manually now
and would like to be able to have the ability to "probe" the height.


I see a Mesa card in my not to distant future,
but for now I want to get a working basic setup.


Thank you

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02 Dec 2011 00:15 #15263 by andypugh
Harry_Y wrote:

Yes all the limit switches will be in series for both machines, since
I will only use one at a time that should be OK for my small setup

Don't forget the HOME_IS_SHARED tag, and you will need them all to home in a separate sequence.

I will need to add inputs later so I can do threading, I would
assume i will also need to add a quadrature encoder for that.
(I am new to CNC threading)

You just need pulse and index. It might be possible to wire such that the probe input for the mill doubles as the pulse for the lathe.
(you need to make sure that the lathe spindle isn't in the wrong place when probing, I guess)

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02 Dec 2011 17:04 #15285 by Harry_Y
Now you have me looking at the threading issue a lot more.

I was looking at this Lathe Encoder kit here:
www.cadcamcadcam.com/latheencoderkit.aspx

It really does not give a lot of info but I would
assume it could be easily enough adapted


Unless there is a better source for an encoder setup for my Sherline lathe

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02 Dec 2011 18:35 #15290 by andypugh
Harry_Y wrote:

I was looking at this Lathe Encoder kit here:
www.cadcamcadcam.com/latheencoderkit.aspx


It looks expensive to me.

I just made my own. It can be as simple as a laser-printed target and a sensor.
This one does quadrature in one chip:
uk.rs-online.com/web/p/products/716-0604/

Though that is not ideal for you, as you need pulse + index.

Threading is the "killer app" of CNC on a lathe.

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02 Dec 2011 19:36 #15291 by Harry_Y
andypugh wrote:

Harry_Y wrote:

I was looking at this Lathe Encoder kit here:
www.cadcamcadcam.com/latheencoderkit.aspx


It looks expensive to me.

I just made my own. It can be as simple as a laser-printed target and a sensor.
This one does quadrature in one chip:
uk.rs-online.com/web/p/products/716-0604/

Though that is not ideal for you, as you need pulse + index.

Threading is the "killer app" of CNC on a lathe.


Yes Far more that I'd like to spend.

I'll have to do a bit of homework

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02 Dec 2011 20:19 #15294 by BigJohnT
Harry_Y wrote:

Now you have me looking at the threading issue a lot more.

I was looking at this Lathe Encoder kit here:
www.cadcamcadcam.com/latheencoderkit.aspx

It really does not give a lot of info but I would
assume it could be easily enough adapted


Unless there is a better source for an encoder setup for my Sherline lathe


Looks like a good project to make when you get up and running. Small timing belts and pulleys can be found at McMaster Carr and encoders at AutomationDirect. Although for the money the kit seems about the right price, but that takes the fun out of it :)

John

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02 Dec 2011 20:24 #15295 by Harry_Y
BigJohnT wrote:

Harry_Y wrote:

Now you have me looking at the threading issue a lot more.

I was looking at this Lathe Encoder kit here:
www.cadcamcadcam.com/latheencoderkit.aspx

It really does not give a lot of info but I would
assume it could be easily enough adapted


Unless there is a better source for an encoder setup for my Sherline lathe


Looks like a good project to make when you get up and running. Small timing belts and pulleys can be found at McMaster Carr and encoders at AutomationDirect. Although for the money the kit seems about the right price, but that takes the fun out of it :)

John



Getting up and running will be nice.

this simple project has grown and grown, but at least the end is in sight

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