[bean_086]

Ok i have my sensors mounted and they work if i only have 1 sensor. however as soon as i try to run them in parallel i can not get them to trip unless they are both tripped. Helllpppp I am abut to pull out my hair.
These are the sensors i am working with I am using 12 v power supply to power them Amazon.com: Amico DC 6-36V 300mA NPN NC 8mm Tubular Inductive Proximity Sensor Approach Switch LJ18A3-8-Z/AX: Home Improvement
I am using this as the BOB
http://www.kelinginc.net/KL-DB25.pdf

[ViperTX]

How do you have the switches wired? Do you have the instruction with the switch or a data sheet?

[jalessi]

Bean_086,

If you are only using one input for multiple NC proximity sensor's they need to be connected in series.

Jeff...

[bean_086]

I dont have any specs on them just what amazon has on there site. I have the + on both sensors to my 12Vdc+. I have the - wire on both sensors connected to my 12v- dc power supply, and i have both of the switched legs conected together to a resistor that is then connected to my breakout board that is associated with that axis 11:x, 12:y if i have just one sensor connected it reads correctly in mach 3 and if i have both connected and tripped it reads correctly in mach 3.

[bean_086]

how would you wire in series

[Al_The_Man]

They are N.C. so if you have them paralleled one will still be closed.
They need to be open collector N.O. to run in parallel.
Al.

[bushwakka]

NPN sensors have the load between the positive and the switch wire, meaning that the sensor is switching the negative part of the load circuit to ground.

Not sure how you have it wired in your CNC but in mine but I connect the switched wire directly to the input. When the switch has something in its proximity range it pulls the switch wire to ground (and hence the input to ground).

I have never looked to see what is it doing when it is not activated (floating voltage or high voltage), but I would install the 2 switches in parallel with no resistor. If either switch is triggered, then this will pull the input low.

Of course for this to work you would need a breakout board that has pull up resistors, so the input is held high unless a switch is triggered to pull it hard to ground.

Attachment 195458
Cheers
Bushwakka

[ViperTX]

Hopefully you've learned not to buy stuff with out any specifications. You can't use a single resistor, each switch must have it's own resistor that way they can trip individually.

Bushwakka...I believe what you have are the NPN NO (normally open) type of proximity switches.

[jalessi]

Bean,

See attached diagram for wiring switches to multiple inputs.

You must use a resistor for each switch.

Jeff...

[bushwakka]

Bean,
The switches you have are unable to be connected in parallel to both trigger the same input with OR logic. Because they both pull the switch wire to ground, they can't be wired in series. You will require NPN Normally Open (NO) switches in parallel for active low ( pulling input to ground) or PNP Normally Closed (NC) in parallel for active high (pulling input to supply voltage).

Viper, you are correct with regards to NO switch.

Cheers
Bushwakka

[jalessi]

Bean,

Here is a example of multiple PNP proximity switches connected to one input in series.
The switches are PNP in this example.

Jeff...