andy and PCW thanks so much for the help.

I will be back in touch when my other cards come  I will probably just
update my build thread on the forum so that the next person having issues
can seach the posts for my issue

regards

Andrew

On Thu, May 21, 2020 at 2:05 PM andrew beck <andrewbeck0...@gmail.com>
wrote:

> hey peter
>
> I am using a 5i25 and 7i76 combo.  and currently supplying power from the
> 5i25
>
> so I don't particularly want to make the computer ground the same as
> everything else lol.
>
> it sounds like I need to connect a external 5v powersupply up to the 7i76
> and change the jumpers around to suit.  and then connect up everything
> again.
>
> I have a 7i89 coming soon and I will wait until then to sort this out I
> think.  I will just disconnect the encoder feedback for now and make some
> parts.
>
> as my servo drives are tuned now.
>
>
>
> its a bit silly that it only just now failed though.  it was working
> perfectly yesterday.
> regards
>
> Andrew
>
> On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace <p...@mesanet.com> wrote:
>
>> On Thu, 21 May 2020, andy pugh wrote:
>>
>> > Date: Thu, 21 May 2020 02:33:16 +0100
>> > From: andy pugh <bodge...@gmail.com>
>> > Reply-To: "Enhanced Machine Controller (EMC)"
>> >     <emc-users@lists.sourceforge.net>
>> > To: "Enhanced Machine Controller (EMC)" <
>> emc-users@lists.sourceforge.net>
>> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>> >
>> > On Thu, 21 May 2020 at 02:22, andrew beck <andrewbeck0...@gmail.com>
>> wrote:
>>
>> >> I read a post you made while ago saying that the 5v and 24v
>> powersupplies
>> >> need to be within a certain threshold to work well.  or else they need
>> to
>> >> be commoned together
>>
>> >This is really a question for PCW. I think that they need to be within
>> >12 (17?) volts to work.
>>
>> There should be no substantial common mode voltage. That is the
>> quadrature source and the 7I76E must have a common ground.
>>
>> The input common mode range on the 7I76E encoder input is -7 to +12V
>> you can easily exceed this (and even damage the reciever chip)
>> if the source and 7I76E do not have a common grouns
>>
>>
>> >> so if I test between the 7i76 mesa 24 field power ground ( this is the
>> same
>> >> power as the servo drive control power)  and the logic 0v on 7i76 I
>> should
>> >> get close to 0v  is that correct?
>>
>> >The important thing is that the difference between + and - is a couple
>> >of volts or so (positive or negative) and in both states the
>> >difference between each input and 7i76 gnd is <12V (or possibly 17,
>> >the number is in the manual)
>>
>>
>> --
>> atp
>> "A motorcycle is a bicycle with a pandemonium attachment and is
>> designed for the especial use of mechanical geniuses, daredevils and
>> lunatics."
>> яя George Fitch, Atlanta Constitution Newspaper, 1912
>>
>>
>> _______________________________________________
>> 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.
>> _______________________________________________
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>>
>

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