G540 and proximity switches

[Al_The_Man]

Looking at the ebay listing they are shown as N.C. , not N.O. as normal.
Al.

[ny_racer_xxx]

Al, regardless if they are NO, or NC, the problem is having the supply voltage bleed onto the control signal. The control signal needs to be either open, or shorted to ground.

These were the ones I purchased: 5pcs SN04 N 5mm Approach Sensor 6 36V DC Inductive Proximity Switch | eBay

Says NO....

[Al_The_Man]

I havn't used the G540 but looking at the schematic for the G540, the inputs are opto isolated and fed from the 12v supply via a 2.2k resistor, so it is simply using the output of the prox to the input without any pull up, and the Prox should sink the input to 12-ve (common) when tripped.
You should be able to use the same supply or at least have the prox and the G540 commons connected.
Max.

[ny_racer_xxx]

Al, I'm using a 18v wall wart, and I see 18volts from ground on the blk signal wire with it not tripped, and dead short to ground with it tripped. I have the PS gnd and the wall wart gnd connected together, there's no continuity from the on the ac side of the wart to the output side..

I'm just not sure about connecting it to the G540 with juice on the input even if it's opto isolated....

Tell me if I'm wrong, but I thought that's the difference between a NPN and a PNP type prox???

CR

CR

[Al_The_Man]

If you have the Prox powered separately to the opto input, the BLK (output) would go to the G540 input but you need to at least connect both commons together.
You could however use the same supply because of the opto isolation.
Al.

[ny_racer_xxx]

Al, I appreciate all of your comments and knowledge, but I do understand that part, and I'm good with the powering the prox, the issue to me is the output to the G540, I'm not sure if the prox is behaving as it should, and I don't want to burn up my controller.

A SN04-N, is suppose to be a NPN NO prox, so with the prox open should I see any voltage on the blk signal lead and ground with it powered up? And with the switch closed, I should see the signal lead shorted to ground?

Thanks
CR

[ny_racer_xxx]

I jumped off this for a bit, I had some real work in there and i built a table for the gantry...

I did figure out how to use those SN04-N Prox, but not directly... No matter what I did, I still had voltage on the trigger going to the G540. So what I found in with my electronic stuff was a solid state signal relay. That has an opto coupler, and what looks like an LED to trigger it. So what I did was take the supply voltage (19volts) figure what resistor I needed drive a LED 20ma (1k) wired it up to an actual LED for testing, worked like a charm. So I put a continuity meter across the switch side of the relay, hooked my resistor and prox trigger and Bingo! Sucess!!!

I just used some double sided tape to hold the sensors in place, but everything worked, I just have to tune the slow zone so the gantry doesn't smash into the sensors or creeps for a long time...

One thing I came across for the G540 which is so stupid simple, I never thought of it.... Why not just use something to ground out for the home/limit sensor? Just like a touch plate does...

[Gilmax]

Here is a quote from a thread on another forum related to proximity switch wiring from Mariss himself.

"I Googled "APS4-12s-e-d" and pulled-up the specifications .pdf for this switch. Here's what you do:

1) Get the "NPN" version of this switch.
2) Connect your proximity switch to the power supply you intend to use for it (+24VDC to "1", GND to "3").
3) Connect proximity switch term "1" to the G540 term 12.
4) Connect proximity switch term "4" to the G540 input you plan to use (INPUT 1, 2, 3 or 4).

That's all there is to it.

Mariss"

If you check out the PDF of that switch and read what he wrote it is pretty straight forward. I wired up my NPN ebay chinese proximity switches the same way and it works without problems.

[ny_racer_xxx]

I tried PNP's, NPN's, wired it every way from Sunday, I get supply voltage at the control pin, no matter what in one of the conditions, not good for the G540....

This was works fine, and they're opto isolated also...

CR