I did not know about these. Thanks so much for posting. So, after the software stops cycling the output pins, the 10 uf cap discharges through 750 Ohm the opto-isolator's LED and the relay opens. I will have to calculate the time delay, but my back of the envelope says about 0.02 seconds. Is that close to what you observe? Or did I miss a decimal place?
It looks like you have a good design and if you can sell these at a reasonable price they should be standard equipment. But I was thinking, Now that we have companies like JLCPCB who can make printed circuit boards and solder components for well under $1 per PCB, I would not want to be in the business of making and selling small electronic devices. I would design this thing so that it used only parts from JLCPCB's "short list" to keep the cost under $1. Post the design files and let people order their own directly from the manufacturer. My concern with this is that it does not catch a failure where only the user space program crashes and the kernel-space task continues to run. Perhaps something else can watch for this? On Thu, Sep 8, 2022 at 2:15 PM <m...@mattshaver.com> wrote: > On 2022-09-08 15:55, andy pugh wrote: > > I rely on the Mesa watchdog. If I was running a system that couldn't > > do that then I would start looking t watchdog circuits, though last > > time I looked I didn't see anything that simply opened a relay if the > > charge pump stopped. > > I actually make this: > > http://www.mattshaver.com/site.php?link=pcbs/cp2estop/index.htm > > It was used in Smithy machines and I have a bunch of them left. Haven't > sold one in years and don't know what they should cost anymore, but if > someone needs one I could look into it! :) > > Thanks, > Matt > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
