Re: Proper pull up resistors for optical limits

Thanks for the help and info!

Frank

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Harvey White <madyn@i...>
wrote:

> On Fri, 14 May 2004 17:12:45 -0000, you wrote:
>
> One way to tell if the emitter is working is possibly the IR

detector

> sheet that Radio Shack sells. Another way is a video or digital
> camera, although it really helps if the camera has an infrared

mode.

> You don't have to take a picture, just look through the electronic
> viewfinder.
>
> Harvey
>
>
>
> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, "fun2b432002"

<fpaul28@h...>

> >wrote:
> >> Wondering if anyone could give me advice on the correct pull up
> >> resistor for my optical limit/home switches. I'm placing

slotted

> >> optical switches on the + side of my X,Y,Z axis to use as limit

and

> >> home. My servos are WorldServo SST1500s and the manual

suggests

> >> using optical switches on the + axis side. There is a diagram

in

> >> the manual that shows connecting them to +5V (which is supplied

by

> >> the servo through the limit switch plug). They show a resistor
> >> between the +5V and the optical interrupter switch but do not

give

> >a
> >> value on the resistor. I assume this is a pullup resistor (I

know

> >> very little about this) and I'm wondering if anyone can help me
> >with
> >> determining which size resistor to use???? The optical

switches

> >are
> >> transistor output type, Min Output 0.5 IC @ 20 mA IF. Another

type

> >> I may use are the same except Min Output 1.8 IC @ 20 mA IF.
> >>
> >> Thanks,
> >>
> >> Frank
> >
> >I still have my test setup of those laying in front of me.
> >I had a hard time getting this to work because the first
> >time I tryed to use it I could not get anything to work,
> >found out much later that the emitter did not work on my
> >optical interrupter switch.
> >That was 1 out of 4 and I sure picked the bad one to start with.
> >The way I found out was when holding it at the right angle
> >to a external light source it started to show a current.
> >The emittler is sort of like a Flashlight shining onto
> >the detector, you want to prevent a external light from
> >shinning directly onto the detector when choosing a final
> >mounting position this could cause trouble.
> >
> >My test setup is wired as follows.
> >
> >(+) +5volt power (D) ground
> >(E) ground (+) Pin 11 on LPT port
> >
> >This worked fine as is.
> >The diagrams I have show a 4.7kohm resistor in line
> >with both (+) lines.
> >seams to work without these to I think they are just
> >for protection.
> >Good Luck
> >
> >
> >
> >
> >
> >
> >
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