Re: [CAD_CAM_EDM_DRO] Re: Proper pull up resistors for optical limits

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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