Re: [Emc-users] PCW, spindle enable for pico pwm-servo, needs 12 volts.

[Peter C. W. <pc...@me...>]

On Thu, 24 Jan 2019, Gene Heskett wrote:

> Date: Thu, 24 Jan 2019 02:33:54 -0500
> From: Gene Heskett <ghe...@sh...>
> Reply-To: "Enhanced Machine Controller (EMC)"
>     <emc...@li...>
> To: emc...@li...
> Subject: [Emc-users] PCW, spindle enable for pico pwm-servo, needs 12 volts.
> 
> On my G0704, which has the OEM motor I'm abusing, I've been studying up
> on how to get a 12 volt enable signal, which currently is a sparkfun
> contraption driven by a std bob signal.
>
> But with the 7i76d, can I feed 12 volts into the pin a vfd's 12 volts
> would normally drive, ground the Spindle- terminal, and get the 12 volts
> for spindle enable from the Spindle Enable+?  Page 18 seems to indicate
> I could source a few ma that way. I'll be using a different pin for the
> pwm signal that amplifier needs, probably the pwm will show u on step or
> dir 4, on tb3?

The ENA+ and ENA- are just a (normally open) switch (OPTOcoupler transistor) 
so can be use as such making sure you dont exceed the current rating (50 mA) 
and obey the polarity


>
> Obviously this is a bridge not crossed yet. And in investigating where
> the pwm might show up, there isn't such a critter in the 5i25 as
> programmed for the 7i76d! Looks like I will have to load a software
> pwmgen and feed it out of a gpio on the 5i25's p2?  Why is this not an
> error?:

Standard 7I76 firmware does not have a PWM generator, there is firmware tha 
replaces stepgen-04 with a PWM gen, if a 5V PWM signal is OK

http://freeby.mesanet.com/5i25_7i76_1px2d.bit

>
> loadrt hm2_pci config="num_encoders=1 num_pwmgens=1 num_stepgens=4"
>
> I'll sort it, but tis a surprise that no pwmgen shows in the halmeter
> menu.  Or is it there, and completely gobbled up by the builtin spinx1
> in the 7i76d? Ack the 2 pass output yes its there. Must figure out how
> to access its raw output... For the pico amp the analog out on tb4-2
> that would feed a vfd's analog input is not usable. Looks like I'll need
> a software pwmgen feeding a gpio on p2, And feed both pwmgens?  Hummm.
>
> Advice needed Peter. I don't think I'm seeing the whole picture.
>
> Thanks.
>
> Cheers, Gene Heskett
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
>
>
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Peter Wallace
Mesa Electronics

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