[Starleper1]

I'm using the CNC4PC C3 board for my axis home/limit switches, and I'm getting strange results. I have the XYZ all connected to the sensor input, and when a sensor is triggered it creates an output to the BOB input. This is the 'normal' operation.

Now this is where it gets weird. Two of the three sensors work as expected with no problems. But when I connect the third sensor it some how disables the two other sensors leaving only the third sensor working. I've been pulling my hair out trying to figure this out, with no luck.

If I disconnect the third sensor, then the two other sensors go back to normal operation. I ordered a replacement sensor but had the same result.

Any of you electronics guys have any ideas?

[Al_The_Man]

Did you substitute one of the ones that are working in the non working spot, to eliminate the sensor itself?
How are they connected?
What type of sensor?
Al.

[Starleper1]

Did you substitute one of the ones that are working in the non working spot, to eliminate the sensor itself?
How are they connected?
What type of sensor?
Al.

Yes it doesn't matter which axis, it's always the same sensor.

I have them connected as the C3 manual shows.

The sensor is an NTE3100

[Al_The_Man]

If it is not the sensor, then it could be the wiring, how about connecting the sensor at the C3?
Al.

[Starleper1]

Already tried that. Same result. It has to be something with the sensors.

I took a couple voltage measurements , and I'm hoping this will give you an idea of what could be going wrong here. First I took measurements with the "working" sensors connected in the un-triggered state. From terminal "C" to terminal "E/K" I get 1.95VDC. From Terminals "A" to terminal "E/K" I get 1.15VDC. With the working sensor in the triggered state, from terminal "C" to terminal "E/K" I get 3.5VDC. "A" to "E/K" remains the same at 1.15VDC.

Now with the "non working" sensor connected, in the un-triggered state, from terminal "C" to terminal "E/K" I get 0.20VDC. Terminal "A" to terminal "E/K" remains the same as the "working" sensor in both triggered and un-triggered state at 1.15VDC

[Al_The_Man]

The pdf details are a bit scarce!
The transistor side is + and E and the diode side is + and D.
There are a couple of ways to connect and it depends on whether the P.S. is common for both sides or separate?
There is a resistor required for each side value depending on the voltage, and the E & D can be the common(s) and the resistors on the + terminals, which is just one of the ways to connect.
Emitter common and collector output or vice versa.
D would be the cathode or K.
The way you have it hooked up and powered would help?
Al.

[Starleper1]

This is how it shows in the PDF manual of the C3. I have all the sensors wired the same.

[Al_The_Man]

Look like you might have a damaged sensor?
Al.

[Starleper1]

I thought so too, so I ordered another one. I ended up with the same exact results.

It's driving me nuts.

I appreciate your time with this by the way.

[Al_The_Man]

BTW, I never order NTE unless I can't help it, they are a substitute semi company, and their prices are typically 200% to 500% more than the original make.
There are many versions of these that I would have sought out first before going NTE.
You can also get Light-ON or Dark-On versions.
Al.

[Starleper1]

Well the sensors came with the board, so I didn't have a choice. I wish I knew what was going on here.

[john-100]

to me it looks like the diagram in the manual is wrong !


I'd expect the photo transistors Emitter (E) and the LED's cathode(K) to be connect to the terminal E/K

the photo transistors Collector (C) to terminal C

and the LED's Anode (A) to connect to terminal A

with close up pictures of both sides of the board
I'd be able to help with detailed tests if needed

John

[Starleper1]

to me it looks like the diagram in the manual is wrong !


I'd expect the photo transistors Emitter (E) and the LED's cathode(K) to be connect to the terminal E/K

the photo transistors Collector (C) to terminal C

and the LED's Anode (A) to connect to terminal A

with close up pictures of both sides of the board
I'd be able to help with detailed tests if needed

John

It looks like all you did was switched the two "+" terminals. I just went out and tried it. No luck the output just stays on or off depending on if I have the jumper set active hi or low.

Like I said the board works fine until I connect the third sensor. And it doesn't matter where I connect the sensor, it's always the same result. To me that says it's the sensor. But like I said I replaced the sensor with a new one and the problem still exists. Whatever the difference between the sensors seems to be the problem. I don't have enough experience in electronics of this kind to make that call. I really need to resolve this. This is all I need yet to finish my build.

[Al_The_Man]

The Terminal E/K looks to me like P.S. common, this could be where to connect the emitter and the Cathode, the collector would be the output and the + side of the LED is the anode (+) side?
That is the way I interpreted it if in fact it worked with the other Slot Opto's?
Al.

[Al_The_Man]

May be this is a loading problem? Do you mean when you connect only the third sensor? But now it seems you mean when ever two are connected and when you connect any third sensor you have the problem?
As a basic premise, sensors like this that operate on light, can only be AND'ed (in series), versions that operate on Dark can be OR'd (paralleled).
Al.

[Starleper1]

What do you mean a loading problem? Let me see if I can explain this a little better.

The C3 board has an LED that is lit or extinguished when an output is present. This is dependent on the active hi or active low selectable jumper. I have it setup as active low (I tried active hi....same result) When I have the Xaxis and Yaxis connected they both operate normally and create an output on the C3 when either sensor is triggered. When I connect the Zaxis, both X and Y become inactive, meaning they no longer create an output from the C3 when triggered. However with all three connected only the Zaxis sensor remains working. If I disconnect the Zaxis sensor, then the X and Y work properly again.

It acts the same way even If I have only one other sensor connected. i.e. Xaxis and Zaxis or Yaxis and Zaxis. The only two combination I can get to work is X&Y.

Here is a picture of my switch setups. They are spring loaded plungers that trigger the sensor when depressed. They are connected to the sensor via a receptacle and molded cord (not pictured). This allows me to move any sensor to any molded cord and I get the same result with any possible configuration of sensors/cords.



This is what leads me to believe it is a sensor problem. Hopefully this better explains exactly what is happening.

[Starleper1]

It's almost like the Zaxis sensor robs all the power from the other sensors. Not sure if that is possible but just a thought.

[Al_The_Man]

If you are trying all combinations of cords and sensors, How are you deciding which is the 'Z'?
Al.

[Starleper1]

If you look at the picture, they all have different mounting styles. The one farthest to the right is the Z axis. I can take that one and plug it in to any of the cords and I get the same result.

i.e. I connect the Z axis switch to the X axis cord and get the same result. What I'm saying is it doesn't matter which cord it's connected to, I get the same result. Ruling out any wiring issues from the machine to the C3 board.

[john-100]

if you look at the picture in post 7
it has E= emitter
D= diode

this should be E = light Emitter = LED
D = light Detector = photo transistor

on boards have used in the past
"E" indicated the photo transistors Emitter connection

I assume you are connecting the sensors in parallel
and the moving flag normally interrupts the light until the limit is detected

if you trace the connection on the C3 pcb board from the terminal A
I expect you will find terminal A is connected to the +5V supply by a resistor
of about 200 ohms (any thing from 100 to 300)

this resistor is intended to limit the current to one LED

I think , on two of the sensors , you will need to use an extra 180 or 220 ohm resistor to connect each of the two LED's anode to the +5V supply


John