[nsantolick]

I'm upgrading my old ULS-25 to the X7DSP controller. The original machine has optical limit sensors with four wires coming out of each. My X7 has inputs for 24V, YLIM+, XLIM+, XLIM-, YLIM- & GND.

How do I connect these???

The limited instructions only show hooking up a simple limit switch with one positive wire per axis & one single ground.

I'd appreciate ANY help anyone can provide me with... :-)

[minicncuser]

try google proximity switch wiring

[bluecuriosity]

Typically the optical limit switches need 5v to operate the led. Then simply connect the two wires you would normally connect to your mechanical limit switch to the sensor.

The typical optical limit I have seen on machines is a normally closed type, the sensor and led are held in a black U-shaped thingy. When something breaks the beam, the circut is broken. There is a parameter setting in the lasercut software called limit polarity, swap this value from negative to positive based on normal-open or normal-closed limit switches.

[cgerber]

I ran into this exact situation on my ULS25PS.

Your optical limit sensors have an emitter and a receiver. Two wires for the emitter, two for the receiver. The receiver is an open collector transistor type of circuit, normally connected in a fashion in which the collector will pull a signal to ground when it is receiving light from the emitter, (ie: when your X and Y axis are NOT blocking the emitter, thus not in the home location). This is a problem because the DSP controller wants to see the ground signal when the X and Y are at home. In my case, the AWC608 which I have, does not have the capability to invert the signal in the software (at least that I could find), so I had to build a transistor signal inverter board to invert the signal so the AWC608 would act correctly when the optical limit sensors were blocked (X and Y home). Now if the X7DSP controller has the added function to invert these in the software, you are in luck and will not need to go to the trouble of building a circuit to invert the signal.

If the X7DSP has this functionality, please let me know, I may consider upgrading sometime.

By the way, if you can accomplish this and maintain using the optical limit sensors, you are far better off than converting to limit switches.

Thanks. Chris...

[bluecuriosity]

yea, AWC708c does allow swapping of normal open/normal closed. I have seen users have an issue with the machine having an issue with the normal closed where the signal is interfered with by the steppers or power supply... they fixed it by changing location of wiring. Inductance is a *****.

[LaserBoyUK]

I ran into this exact situation on my ULS25PS.

Your optical limit sensors have an emitter and a receiver. Two wires for the emitter, two for the receiver. The receiver is an open collector transistor type of circuit, normally connected in a fashion in which the collector will pull a signal to ground when it is receiving light from the emitter, (ie: when your X and Y axis are NOT blocking the emitter, thus not in the home location).

Hi Chris

Could you elaborate on this a little - I think the pairs are red & green (emitter ?) and white & black (receiver ?)
Is it 5v supply to the emitter - do I need any current limit eg 180ohm resistor?
and the same with the receiver any current limitation ?
Did you have a circuit diagram ?
I think my DSP allows me to swap high and low so I dont need the invertor

thanks
Adrian

[nsantolick]

Ugh. I'm STILL looking for an answer. Can anyone offer any assistance please?

[nsantolick]

I wonder if the y+ and y- mean spaces to wire home sensors AND limit switches on the y-axis???

[nsantolick]

I ordered 2 of these:

https://smile.amazon.com/gp/product/B00J3MHT1E

I read 36 volts off of 4 of the six terminals, with one being the ground. Not sure why one of the y- points is just giving me around 3 volts?

Does anyone think this is a bad idea? I'll use one on each of the positives so my 5v optical switches will work, I think. lol