Re: How to get a signal to controll spindle speed?

["Patrick Riedlinger" <patr-at-precidesign.com>]

Jacob:

I am going to stick my neck, out....because I am a Newbie too.

Ray, please step in if I get this wrong.

Ok--EMC has two pins that control Spindle Forward and reverse. They are
mutually exclusive--that is, when one is on, the other is off. So, it should
be easy for you to turn the laser on/off.

However, the spindle increase/decrease pins just output a pulse (of duration
unknown to me). Everytime you push the Spindle Increase or Decrease on the
EMC control panel, it puts a pulse on these respective pins.

BTW, the pins are defined in the emc.ini file, under Aux output, using the
Bridgeport IO definition.

So it's going to be really hard to PWM your laser with the Inc/Dec signals,
since they only put out a (single) pulse every time it is actuated.

I suggest you use some kind of counter (SN54HC4060) with an oscillator you
control with the EMC pins to produce a up/down digital signal you can input
into some DAC to produce a voltage for a VCO

In order:

EMC to Logic
Logic to Counter
Counter to DAC
Dac to VCO
VCO to Laser

This is off the cuff, so there are many better ways to do this, I'm sure.
Maybe some other suggestions from the friendly folks in the EMC newsgroup? I
am not an Electrical engineer, and my experience is from years ago. I bet
there is some "canned" IC chip that will do many of the functions that you
need, nowadays.

Anyway, I will need to be making a similiar circuit to control the spindle
on my (cheapie) milling machine. I will also need to PWM the spindle, since
I am planning to use a triggerable triac type of circuit. I would be
interested in collaborating with you or other EMC users to figure this one
out.


Pat Riedlinger





Ray, if I screw this
----- Original Message -----
From: "Jacob Kranendonk" <j_kranendonk-at-yahoo.com>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Friday, May 17, 2002 8:36 AM
Subject: How to get a signal to controll spindle speed?


>
> Hi list,
> Can anyone tell me how typically a mill with
> controllable spindle speed out the emc is being set
> up? I want somehow a possibility to controll
> laserpower by the emc software. I think I could use
> the "spindle speed" command for this purpose. But how
> do I get a signal for this, out of the emc? Does this
> take extra hardware (like a digital/analog converter
> or something), or is there a way to get a digital
> signal to. All I need as a final signal to the laser
> is a PWM (Puls With Modulated) TTL signal at 5KHZ.
> Does anyone have a sugestion how I can achieve this,
> perhaps with the help of some simple IC? Many thanks
> in advance, Jacob
>
>
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