--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Brad,
>
> Zero(ish) and four(ish) levels are proper levels.  But there should be TWO of
> them for A and also two of them for B.  Sometimes called A+, A-, B+, B- or
> sometimes called A, /A, B, /B.  The complementary signals are simply inverted so
> that when the A+ signal is high the A- signal is low, and similar for B+ and
> B-.  The receiver circuit, Kanalog in this case, compares the levels of the two
> signals.  Which one is higher determines the state of the signal.  This is what
> provides the great noise immunity.  There might be a 6V ground level difference
> between the driver and the receiver so the signals are both switching between 6V
> and 10V rather than 0V and 4V and the system will still work properly.  If you
> are only connecting one of the two signals the behavior will be erratic as
> the other input that Kanalog will be comparing to will be floating.   In the
> case that you only have single ended signals (only one A and one B), you can
> connect them directly to KFLOP JP5 which bypasses the Kanalog differential
> receivers.  But this will be much more noise sensitive.
>
> I hope this helps
> TK
>
>
>
>
> ________________________________
> From: b.parcels <bparcels@...>
> To: DynoMotion@yahoogroups.com
> Sent: Wed, April 6, 2011 11:07:13 AM
> Subject: [DynoMotion] Kanalog Encoder issues
>
>  
> Hi all,
> I am sure I'm just doing something goofy here, but for the life of me, I cannot
> get these darn encoders to work...
>
> I've got several Renishaw linear encoders that should be putting out rs422A
> digital signals... I was having very erratic behavior (not working at all) when
> connected to the KAnalog board, so I am looking at them on an oscilloscope:
>
> Look like great little square waves - even cleaner if I terminate them
> properly... HOWEVER ... It looks like a single-ended signal - I only see
> zero(ish) or four(ish) volts. The signals are proper quadrature form, and in
> sync - just look single-ended (and perhaps not full strength).
>
> I haven't actually worked with rs422 before, but my understanding is that I
> should be seeing plus 5(ish) to minus 5(ish) volts... is that not correct?
>
> For what it's worth - the encoders are powered directly from the KAnalog, and
> that has an ATX PSU for KFlop and itself.
>
> Are my encoder differential drivers shot - if so, can I just buffer the signals
> somehow? Potential wiring issue? Am I just being clueless?
>
> Thanks so much for any suggestions!
> -Brad
>
> P.S. Sorry about all the (ish)s... I think I've lost it
>

--- In DynoMotion@yahoogroups.com, "b.parcels" <bparcels@...> wrote:
>
> Hi Tom,
> Thanks for the clarification... unfortunately, the problem remains - I do have A+/A- B+/B- - however, it's almost like the complimentary signal doesn't drive... A+ referenced to ground doesn't show signal, A- referenced to ground shows no signal, same for B+, B-... It's only when referencing A+ to A- that the signal appears. As you describe it, a scope signal between A+ to A- should then switch between +4(ish) and -4(ish), right?
>
> Cheers,
> Brad
>
> --- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@> wrote:
> >
> > Hi Brad,
> >
> > Zero(ish) and four(ish) levels are proper levels.  But there should be TWO of
> > them for A and also two of them for B.  Sometimes called A+, A-, B+, B- or
> > sometimes called A, /A, B, /B.  The complementary signals are simply inverted so
> > that when the A+ signal is high the A- signal is low, and similar for B+ and
> > B-.  The receiver circuit, Kanalog in this case, compares the levels of the two
> > signals.  Which one is higher determines the state of the signal.  This is what
> > provides the great noise immunity.  There might be a 6V ground level difference
> > between the driver and the receiver so the signals are both switching between 6V
> > and 10V rather than 0V and 4V and the system will still work properly.  If you
> > are only connecting one of the two signals the behavior will be erratic as
> > the other input that Kanalog will be comparing to will be floating.   In the
> > case that you only have single ended signals (only one A and one B), you can
> > connect them directly to KFLOP JP5 which bypasses the Kanalog differential
> > receivers.  But this will be much more noise sensitive.
> >
> > I hope this helps
> > TK
> >
> >
> >
> >
> > ________________________________
> > From: b.parcels <bparcels@>
> > To: DynoMotion@yahoogroups.com
> > Sent: Wed, April 6, 2011 11:07:13 AM
> > Subject: [DynoMotion] Kanalog Encoder issues
> >
> >  
> > Hi all,
> > I am sure I'm just doing something goofy here, but for the life of me, I cannot
> > get these darn encoders to work...
> >
> > I've got several Renishaw linear encoders that should be putting out rs422A
> > digital signals... I was having very erratic behavior (not working at all) when
> > connected to the KAnalog board, so I am looking at them on an oscilloscope:
> >
> > Look like great little square waves - even cleaner if I terminate them
> > properly... HOWEVER ... It looks like a single-ended signal - I only see
> > zero(ish) or four(ish) volts. The signals are proper quadrature form, and in
> > sync - just look single-ended (and perhaps not full strength).
> >
> > I haven't actually worked with rs422 before, but my understanding is that I
> > should be seeing plus 5(ish) to minus 5(ish) volts... is that not correct?
> >
> > For what it's worth - the encoders are powered directly from the KAnalog, and
> > that has an ATX PSU for KFlop and itself.
> >
> > Are my encoder differential drivers shot - if so, can I just buffer the signals
> > somehow? Potential wiring issue? Am I just being clueless?
> >
> > Thanks so much for any suggestions!
> > -Brad
> >
> > P.S. Sorry about all the (ish)s... I think I've lost it
> >
>