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Author Topic: hello there - help please, how do you do the light sensor limit switch - 3 wires  (Read 2257 times)

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Offline nobby

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https://docs.rs-online.com/82f4/0900766b812c8e16.pdf

10v
not worth the risk?

pardon my ignorance, but i dont undestand 10v in and 28v out
?

Offline nobby

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its all a bit nice and stock with them
hmm
its a lovely machine, i have already bodged the motors on....

Offline MN300

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Quote
pardon my ignorance, but i dont undestand 10v in and 28v out

The input voltage powers the photosensor. The maximum voltage is 10V. However 5V is all it requires.
The output uses an open collector transistor that acts like a normally open contact to ground, just like a mechanical switch. The maximum voltage it can withstand is 28V.

There are many low cost voltage regulators on eBay, Here is one example.
https://www.ebay.com/itm/403714437758?
You can use it to reduce your 12V to 5V for supplying the photo sensor.

This one's output is set by two areas marked A and B where you blob two pads together with solder.
There is a chart to show you how to set the voltage. For 5V there's no blob on A and a blob on B.

Offline nobby

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hello
i have six of them 2 on each axis
can i get one of these

12v in red to 12v on nvem breakout board, black to ground

5v 3a out
yellow to pin 1 vcc on all 6  sensors
black to ground on all six sensors

then simply take vcc out
x axis x++ and x--
y axis y++ and y--
z axis z++ and y--

in mach have the same pin for both switches on the same axis
send it to home whichever way
?
thanks

Offline nobby

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thinking about it, i crashed my last machine a lot on soft limits - not having any travel after the switch

rookie mistake I hasten to make again


Offline MN300

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Yes you can power all the sensors with one supply, its 3A output is enough for 100 30mA sensors.

Quote
then simply take vcc out
x axis x++ and x--
y axis y++ and y--
z axis z++ and y--

I'm not sure what you mean by vcc out, do you mean the output of the sensor? It's not Vcc, The output just makes a connection to ground when on.
You can connect two of these outputs to one input. The input needs to be the type that works with a switch contact to ground

Offline nobby

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ahh
so there is no ground for it as its used to step the 12 volts down to 5

?

so it is impossible

-great

2 wire limit switches
keep it simple

overtravel 10mm for soft limits

!!!


Offline MN300

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This is what I think you are asking for, two switches from the same axis connected to one input

Offline nobby

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12v out
input pin x axis ++ -- limit
ground

i can take the 12v  and the ground on the controller step that down to 5v and use the ground for the returning 5v to ground

the ground pin can be used for both 12v and 5v was confusing me
-or it isnt possible?

I am a novice
« Last Edit: February 09, 2023, 04:07:40 PM by nobby »

Offline nobby

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oh, and thank you