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Ok I kind of understood that lol

Forgive me because the following follow up questions. They are really dumb and I know it. Teaching an old dog new tricks isn’t easy.


If both the proximity sensor (SN04-N) and the optical switch (OPB830) are rated for up to 30VDC the resistor is needed because of the mA my board would be sending? I'm assuming that's what you meant when you said, "it has to limit the current to 50ma max.”
It looks like from my board specifications that it is a 24v 500mA supply (page 64 of the manual).
The Optical switch has a max of 50mA but the Proximity sensor says 5mA.
So I’d need one resistor to bring one 24v supply from 500mA down to less than 50mA and another resistor on a 2nd 24v supply from 500mA to less than 5?

And I have absolutely no clue what to search for to get the right resistors for those. Any chance you could send me a link to them on say amazon so I know I’m getting the right ones?

Wiring for the optical switches:
Reds/anodes = power
The black wires, the cathodes, you said are grounds so they can be combined and grounded to the machine ground I have set up near them already?
White wires, the collectors, are combined in my current configuration but I still don't understand what they would connect to on my board. I’m kind of thinking they would be to the 0V input on my board as that is common for that series of inputs? But still confused.
And then the greens, the emitters, would go to the individual inputs in that section of inputs?

Or am I completely wrong as usual?

For the proximity sensors:
I get the brown/power wire.
The black is sending the signal which goes to the input on my board.

The specs I just found for this sensor shows the blue as 0V & ground so that could also go to the machine ground or does it need to go back to the 0V on my board?

I’m sure the link you sent with the electrical diagrams actually explains this but I get very confused looking at them.

Thank you again for putting up with my stupidity I'll owe you big time

[Al_The_Man]

Ok the LED's are rated for 50ma, and your supply is 24vdc so R=E/I , 24/0.05 = 480 ohms, 475 is the closest match, you can use either in series with the cathode or anode of the input Opto diode.
IOW source from 24vdc with 475 resistor to anode or sink to 0v from cathode with same value.
On the output of the OPB830W11Z the connection is as shown in earlier links/diagrams depending whether you need to sink or source the output.
You normally would connect directly to the inputs on the BOB .
Pages 17-21 of the BOB manual/

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Thank you for trying to help me.

I get the resistor portion now and have them ordered off amazon.

The limit switches are easy, and I have that now. You’re saying the 0V is not a machine ground even when it says it’s a ground, but it goes back to the board to the 0V there.

As for the rest, I must not be conveying how limited my knowledge is of circuitry and therefore I'm not explaining my questions well enough for you to explain it to me in a way I understand. As I said before I just don't understand electrical diagrams so saying to connect my switches like the earlier diagrams show doesn't help me at all.

Maybe you're approaching this like a teacher getting the student to work through the problem themselves instead of giving me the answer but that isn't working because I still don't get it

I plan on sending power from the board to the Anode/red wires of all three homing switches. I'm also assuming you mean the Cathode/black wires should go back to the 0V on the board and not to the machine ground. This would mean all of them three of them need to be combined because I don’t have that many 0V inputs.

Then I’m lost where the collector/white wire and the emitter/green wire connect to.

Pages 17-20 are helpful for me to a point but then they start relying on circuitry diagrams again and the pictures of how the three wire switches help but I’ve got four wires, so I’m lost again. I know the signal the switch is sending goes out on one wire and I’m assuming that would be the collector, which goes to input on the board, but what does the emitter wire go to??????

Thank you again for putting up with me and if you’ve dumbed it down the best you can already don’t worry about spending anymore time on this.

[Al_The_Man]

If I have time tomorrow I can perhaps sketch it out. I have never used that board at all, I assume you are using a 24v supply?

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If I have time tomorrow I can perhaps sketch it out. I have never used that board at all, I assume you are using a 24v supply?

Thank you I’m sure it’s very simple I’m just not grasping it.

And yes a 24 power supply to the board.

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Attachment 490134

I was finally able to get approved into the forum for the manufacturer of the MachBob3 (MB3) board with ESS. It's not a very active board probably due to the fact the registration portion is not working as intended.

The moderator, who is also the person that's name was on the orders and sales emails when I purchased the MB3, replied with the attached picture. I replied with "This switch can take up to 30vdc but no more than 50mA so wouldn’t it make more sense to use 24v with the correct size resistor instead of 5v?" Since he's in Thailand I'm guessing I'll hear back later.

I also wanted to ask him which connections from all three switches were safe to combine to cut down on the number of wires needed and number of physical connections on the board.

[Al_The_Man]

The resistor size for the LED on 5v is 100ohm. It is optional, depending on what supplies are on hand.
Typically you normally use 24vdc for wiring out on the machine, 5v is for local and non sensitive (less noisy) areas.
I didn't get chance today but if need I may have time tomorrow AM.for the sketch.

[Dbl_Tap]

The resistor size for the LED on 5v is 100ohm. It is optional, depending on what supplies are on hand.
Typically you normally use 24vdc for wiring out on the machine, 5v is for local and non sensitive (less noisy) areas.
I didn't get chance today but if need I may have time tomorrow AM.for the sketch.

And the limits and home switches are definitely out on the machine so I’d want them running 24v

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Attachment 490194

He updated his drawing for me and said that 24v is fine but he drew in 3 separate resistors at each switch. I would have done one then split the power but I'm getting a lot of resistors so that's no big deal.

[Al_The_Man]

Yes, each Opto requires its own resistor! You cannot use a common one.
Why did they specify such a high value?? Result <8ma.
The 470 ohm resistors will give you a tad under 50ma when you factor in the diode drop.

[Dbl_Tap]

Yes, each Opto requires its own resistor! You cannot use a common one.
Why did they specify such a high value?? Result <8ma.
The 470 ohm resistors will give you a tad under 50ma when you factor in the diode drop.

Yeah I thought it was strange he specified one that big. I thought I was missing something lol