On Monday, 18 April 2022 10:38:10 EDT Peter C. Wallace wrote: > On Mon, 18 Apr 2022, gene heskett wrote: > > Date: Mon, 18 Apr 2022 04:19:27 -0400 > > From: gene heskett <ghesk...@shentel.net> > > Reply-To: "Enhanced Machine Controller (EMC)" > > > > <emc-users@lists.sourceforge.net> > > > > To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> Subject: [Emc-users] nother Q for > > Peter > > > > Greetings; > > > > How does the A/D on a 7i76D handle overvoltage? I'm considering a > > long > > tailed vfet pair with a 22k pullup to 42 volts. Does it just goto > > full > > scale at an $FF output, or will that blow something? > > Full scale (inputs will take up to 100V indefinitely) > but adjacent inputs may read incorrectly if more than about > 50V is suppled (due to current injection into parasitic > transistors related to the input ESD diodes of the CPU) Excellent news Peter, I'm off to the races then. I think there's current gain enough in a TIP-120 60 volt darlington to make my idea work. $2.95 a 10 pack from MPJA.com. With a long-tailed pair, useing the right one for a threshold adjuster, so it turns down a pwmgen starting at around 16 psia, it ought to work just dandy.
What value R to 42 volts would be full scale, effectively limiting it to 36 and change (full scale) at the input? In that manner the ESD diodes should disappear. Dead accurate isn't required, just decent repeatability. Thank you, stay well, both of you. > > 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, 1940) > > If we desire respect for the law, we must first make the law > > respectable. - Louis D. Brandeis > > > > > > > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > . 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, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
