Thanks Jon. You're right - the waveform is from the raw photosensor outputs.
Would it be posible for you to provide a circuit diagram using the LM193
please? I have tried an op-amp (Max942) as I have a few kicking around. I
connected A+ to one i/p and A- to the other following a diagram that I found by
a University student working on a Puma. It doesn't work!
Thanks
Jonathan
----- Original Message ----
From: Jon Elson <[EMAIL PROTECTED]>
To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net>
Sent: Thursday, 4 September, 2008 2:31:12 AM
Subject: Re: [Emc-users] Puma560
Jonathan Hancock wrote:
> Hi all - just a quick update on my Puma project.
>
> As a thought, the output from the original encoders is a sin/cos
> waveform (to see goto http://www.flickr.com/photos/[EMAIL PROTECTED]/ ). I
> will try to convert this low level signal into a ttl level square wave
> using an op-amp. The encoder has a pair of leds and photo sensors in.
>
OK, looking at the very asymmetric waveforms, I'm guessing these
are just raw photosensor outputs, and not real sine/cosine
signals ready to be interpolated. I can't tell the voltage
levels from the pic, but a simple comparator circuit should be
able to convert to TTL levels.
Don't use an op-amp, they are too slow and don't have a
"digital" output stage. Use a comparator such as the LM193.
> I am looking at using a pic adc to gain limit and homing signals from
> the pots on the back of the motors. This is looking quite promissing.
>
> I've installed ubuntu and emc2 on my machine and now baffled!
>
> Jon - am I sorting the correct things out to interface to your cards?
I guess so. You would need digital A, B and Z signals, and a
contact closure or opto-isolator output for the limit signals,
and home switch simulation.
Jon
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