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Probe Wiring
« on: June 03, 2014, 09:26:25 AM »
Hello guys!

I am still on the wiring part, the progress is not going as quickly as wanted but surely we are doing some progress.

Regarding the probe for auto tool Z zero and auto tool height measurement, I am in doubt which way to go and what is better.

I am in use of CSMIO-M which gives me freedom for my input polarity. I've done so that 6 of my inputs are NPN logic and the other 6 are PNP logic. So, in other words, half of them are preloaded with 0V from power supply and the other half is preloaded with 24V from power supply and they expect the opposite polarity to close the loop and have the input ON.

I intend to have two separate two plates, installed on two different locations for my machine. On will be mechanically fixed and will not be able to move. That will be used for auto tool measurement. The other one will be movable and will be put above the part before the auto tool Z operation is started. Of course they both have to be wired to the Probe input.

But my question is more on which polarity to use for the diagram. I basically see two solutions:

Solution 1) Attach 0V from power supply to the tool bit before doing the auto tool operation. Put a wire from the touch plate to the CSMIO input. This way, when the tool bit touches the plate, the electricity will be conducted through the touch plate and thus to the CSMIO input. I'll have to use one of my NPN logic inputs(as explained above).

Solution 2) Apply 0V to the tool bit, apply 24V to the touch plate through a resistor 3,1 kOhm. Then use a wire from the other side of the resistor to the CSMIO input. This way I will get constant 24V and when the tool bit touches the plate, the current will flow to the 0V and the CSMIO input will be OFF. I will use the Mach3 input invert option(low active).


I am just not sure which idea is better. I am also not sure what happens if my machine is Earthed and I apply 0V at the tool bit (which is DC ground). Will that cause any shock to the electrical system?


Also, I am not sure how to combine two signals from two touch plates. Any CSMIO-specific probe wiring schematics?


 

Offline MXJ

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Re: Probe Wiring
« Reply #1 on: October 10, 2014, 04:38:25 PM »
What solution did you use in the end, as I am now at this stage of my build?
Re: Probe Wiring
« Reply #2 on: October 18, 2014, 03:45:11 PM »
Hi MXJ,

I am sorry to see this 8 days after the posting, I didn't get an email for some reason.

Anyway, at the time of writing here, I also contacted CS Labs and they suggested something very simple. In order to feel safe for the CSMIO controller, they suggested that I use a separate 24VDC power supply, only for the auto touch plate. Baring in mind the input needs milliampers to get ON, the smallest 24VDC capacity will make it for you. I intended to buy a 0.42 A from Mean Well but ended with a 1A only because the first was not available locally and I didn't want to wait. Of course, the bigger the power supply, the bigger the current consumption. It is your choice.

Basically, I have a big clamp-like wire, which is preloaded with 0V from the separate power supply. When I am about to perform auto tool zero, I attach the clamp to the tool bit. The touch plate has a big (4 mm ^ 2 wire) soldered to it. The other end goes directly to the negative(-) of the CSMIO input used for auto tool zero. The (+) of the same input number is wired to 24VDC again from the separate power supply.

I feel that I need to mention I didn't go for two different touch plates. I only have one which can get to every part of the work table of my machine. For now, I haven't implemented the auto tool measurement because it is not necessary for the way I work.

When the tool touches the plate, the 0V goes through the touch plate to the CSMIO input and closes the loop which stops the feeding. I've measured my plate's thickness with a micrometer and have inserted a special line in the CS Labs's VB script to set Mach3's Z coordinate to that thickness.

I had some hard time finding the image I got from them in my CS Labs folder. Never mind, I found it in my inbox. If you have any questions on this, I will be glad to help.
« Last Edit: October 18, 2014, 03:47:41 PM by penkomitev »

Offline MXJ

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Re: Probe Wiring
« Reply #3 on: October 19, 2014, 02:14:48 AM »
Hi Penkomitev

Thank you for posting the information. I will go with this solution.

Regards

MXJ
Re: Probe Wiring
« Reply #4 on: October 19, 2014, 02:29:44 AM »
Hi,

last night I was in a hurry to write the post and I am not sure it is very clear what "clamp wire" is because I feel it is my contribution to the English language.

Mine is maybe a little bigger than the one attached. I apply it to the tool cutting part or to the shank, dependent on which one is more available.

The wire(4 mm ^ 2) is soldered to one of the sides. This thing is pretty obvious from many Auto Tool Zero videos on YouTube.

You can use any wire, I just used the biggest one I had in order to have mechanical strength. Just make the wire as long as it could reach your entire worktable, even the farest points.