Re: Linear Encoder Question

> From: TADGUNINC@...
>
> Mo,
> The piece I was inquiring about is shaped like an "F" with a single slot

in

> the opposing faces of the legs has a drawing of a diode on one of the

legs.
Then it is definitely an photo interrupter (like the things inside your
mouse or printer paper sensor)
The leg with the diode symbol contains the LED

> I think I can figure out, with a diode tester, which pins are for the led?

That may be misleading if it contains signal conditioning (I am sure it does
because it only has 3 leads)
Does the model number begin with GP ?

>do you think it would work off of VCC or a smaller voltage?

The Sharp signal conditioned units almost always work off 5v there is the
odd exception which uses 24v !

> And finally, am not familiar with these types of devices, would you use

the output to drive a FET

> or transistor to gain some useful current capabilities or would you be

able

> to hook it directly to one of the limit/home circuits of one of the
> driver/controllers?

Being a signal conditioned unit it contains a limiting resistor for the LED,
a voltage regulator, an amplifier with schmitt trigger
and an output transistor, you will not need anything other than a resistor
or two to interface the output to the home/limit switch circuits.
Your pin functions will be VCC, Gnd & Output the output will normally be the
collector of the output transistor ( the emitter is internally connected to
Gnd )
The output pin should be connected to VCC using a 10K resistor - take
another connection from the output pin and connect it to the home or limit
circuit.

You need to work out the pinout, the three most common are:

1=VCC 2=Gnd 3=Out
1=Gnd 2=Out 3=VCC
1=VCC 2=Out 3=Gnd
Try them out using a 10K resistor from Out to VCC and a meter across the Out
and Gnd pins - stick something into the slot and the signal should toggle
state.

Finally, I would not recommend the use of an opto sensor in a machining
environment with cooling fluid, swarf, metal dust etc.
a mechanical switch is far more reliable here.

Mo