Most of us just use a wire as a jumper to check between pins, no need for a switch unless its permanent as a bypass or similar.

   Anyway hopefully this diagram will help.
 http://www.homanndesigns.com/pdfs/EN010_V8.pdf

  It shows how he is using a 48v power supply to help run his relays.

Just a quick update. I decided to buy the C3 breakout board since I could not find an opto that I KNEW would work. I should be getting it early next week.

In the meantime, my hall effect switches came in the mail, and I built  a circuit.

Basically what I am doing is taking the output from the hall switch and going into a NPN transistor through a 10k resistor. The collector goes to the ground of the G540 which connects to pin 12, and the emitter is going to pin 1 (10) as an input on the G540, and I am using a 12V power supply to power the circuit and connecting ground to the G540 ground as well.

I breadboarded the circuit and it was working as expected yesterday. As I moved the magnet past it, the index light in diagnosis toggled. As quickly or slowly as I moved the magnet past it, it seemed to respond.

I than soldered the actual circuit today, hooked it up and not working. I spent two hours troubleshooting it with a multimeter, and it seems that my 10K resistor is not working properly. Ironically I tested the resistor before soldering, and it was working fine, so something happened to it while soldering. I can see that at the connection from the start of the resistor from my output of my hall switch, I am getting about 6V, when switched on at the other end of the resistor, I am getting nothing at all. When I use the ohmmeter function of the mulitmeter, I am getting no reading at all on that 10k resistor.

So hopefully that is the problem, but I ran out of time to replace the resistor. I hope to be able to do that tomorrow morning and hopefully this thing will work.

At that point I will be able to compare this circuit to the C3 to see which one works better. If both are equal, I will use whichever one is easier to mount/protect.

I thank everyone again for all the help, particularly Hood!

Having C3's on my lathe and mill spindles, I can vouch for their ease of installation and reliability.  My electronics knowledge is weak so I decided to buy them instead of just an opto sensor & resistor as advised by many.

I use the C3 also. But not with the 540.
Be sure to post your final results, thanks.
Russ

Having C3's on my lathe and mill spindles, I can vouch for their ease of installation and reliability.  My electronics knowledge is weak so I decided to buy them instead of just an opto sensor & resistor as advised by many.

Cool, good to know. The one thing I am not sure about is how I am going to mount the opto itself, it seems like the wiring of the C3 is very straightforward, but it does need to be carefully mounted over a disk it appears.

Seems like the hall effect would be much easier, stick a magnet somewhere and mount the hall close by, we will see.

I use the C3 also. But not with the 540.
Be sure to post your final results, thanks.
Russ

Thanks Russ, most certainly will!

By any chance, would any of you guys using an opto or the C3 show me how you mounted the disk and the opto sensor to your lathe via a pic?

I am having a hard time figuring out where and how I want to do this.

Here is one on my "homebrew" lathe.
Just a disc slid on the shaft behind the pulley.

On another older Hardinge, I put it inside but pulled the spindle as it was between the headstock bearings.

Over time, the opto will accumulate dust and oil mist (if present). These are the only problems I've had.
The operator blowing parts off to gauge them puts a fine mist in the air .... it WILL eventually find the sensor. Every month or so we need to clean/flush the lenses with contact cleaner.
I like the magnet idea, easier to keep metallic bits away than the slightly dirty atmosphere. 

Thanks Russ! Looks good.

I got the magnet kind of working, but not reliable right now.

I think I need to play with the sensitivity of the transistor to get it more accurate.

I agree that the Magnet seems like it could be easier to keep clean, just a simple wipe every now and then would probably work.

Never had a problem with the optos needing cleaned when I used them but they were away from any belts so no stoor from them.
Dont think I have any pictures now of my setups when I used optos, I now just use the encoders on my spindle motors.

Hood