Thread: How should we wire the photoswitchs?
View Single Post
  #44   Spotlight this post!  
Unread 15-01-2011, 17:02
iambujo iambujo is offline
Mentor
FRC #2729 (Storm)
Team Role: Mentor
  
Join Date: Feb 2008
Rookie Year: 2008
Location: NJ
Posts: 86
iambujo is a name known to alliambujo is a name known to alliambujo is a name known to alliambujo is a name known to alliambujo is a name known to alliambujo is a name known to all
Re: How should we wire the photoswitchs?
So I worked with the students today to explore the sensor for wiring and sensitivity. Long story short I read this thread prior to attempting any wiring. When we looked at the the voltage at the DSC inputs with a DC volt meter, the sensor appears to sit at ~.7V for logic low and 3.99V for logic high.

Anyone else see this? I honestly don't know if this is expected. With the pull-up built into the DSC I wouldn't have expected so much voltage drop for the high.

At first I assumed we would have to build a circuit for pull-up/pull-down, but after reading the thread about the open collector and DSC built in pull-up I followed the logic. (the data sheet that wasn't too descriptive)

So, does .7 and 4V make sense? Are they within the tolerances for digital high and digital low in the DSC and cRIO? I am assuming if we had been able to sync up with software today they would have just been able to use the VI and be on their merry way. But we probed the values, and then got to thinking. And then that took us on tangents.

Thanks!