Power Plasma control pinout for CNC

[Loki]

I'm building an interconnect for a CNC table but the unit is still in the mail. I could figure all this out when the unit comes in but I wanted to see if I could get some parts ordered sooner.

From the pictures it looks like a 4 pin male connector with a threaded outer housing is used for the control lines. However from a previous post you mention that your using a 7 pin connector for the new IGBT line.

For a Power Plasma 70, although I think the control connectors are all the same, what is the pinout and what kind of connector is that?

The pinout could be various things. From the 7 pin connector it looks like pin 3 and pin 5 are power/ground, pin 4 ties into an A/D converter of some sort, possibly on a micro controller, pin 6 and pin 7 are not used and so are shorted together, while pin 1 and pin 2 are connected usually to the trigger switch and themselves are either power and ground with one of them having a line to a micro controller to detect a voltage drop or rise when connected.



If its like in the pictures and has a four pin connector, then most likely pin 1 is power, pin 3 is ground, pin 2 has a current limiting resistor tied to ground and a voltage sense line going to a micro controller to determine a short to power, and pin 4 is the middle pin connect for a potentiometer voltage divider.

I need to know how accurate the above musings are and what the voltages are like. Are they 3.3v, 5v, 12v, or something else?

Finally, the strategy I'm considering using is a simple low current relay switch or transistor switch to control the pins and a voltage sensing loop of wire to tell when the plasma cutter has switched from the pilot arc mode to actually cutting.

As mentioned in another thread, the case will be grounded to true ground and we will make every effort to isolate the motor controls from the table frame.

Thanks in advance.

[everlastsupport]

The Power Plasma has a 4 pin connector. If I recall 1 and 2 can be shorted to fire the unit. You would have to pop the cover and look.

Not sure about any power coming from the remote connector? You are talking about just a plasma cutter right? Not a 4-1 unit?

[Loki]

Yeah I noticed that the powerplasma only had a contact start wired into the machine. I was hoping to be able to easily interface with the machine for cnc better.

I couldn't find an adequate plug to mate with the control switch so I wired in a new one. It isn't as robust but considering this thing is for cnc work it'll do. I also noticed that there were some features missing that a cnc machine could use, but would be easy to add. I've been mired in delays because the machine didn't ship with a torch head for some reason, but in theory that issue is fixed.

I've got a wiki that details what I did to interface with the plasma cutter. Its dirt simple, although I'm afraid I'm going to need to do some more work to get decent cuts. Top of the list is detecting when the plasma cutter switches over from pilot to the clamp. I also want to be able to dynamically adjust current on the fly, which should be possible as well. To do this, there is a multiplexer in the machine that switches from the pilot arc control circuitry to the potentiometer current knob on the front of the machine. So, I just detect when this hand off occurs, and I can be somewhat sure that its time to cut! I could also insert into place a digital variable voltage divider to replace the potentiometer. Obviously adding this much circuitry is more trouble than adding in a pc-to-plasma cutter switch, not to mention shielding it and such.

My next plasma cutter purchase will hinge on how easy it is to interface with, or I might be purchasing one for the case and the parts and strip out the control interface to replace it with a microprocessor.

Here is the link to the work I'm doing, forgive the state of the documentation as in theory it will get cleaned up someday. http://openfarmtech.org/index.php?ti...ch_Table_Build

[performance]

The plug connectors for the front of the machine are fairly inexpensive, if that is what you are talkng about.

BTW, Parker is Chinese. You had it listed as American...unless they have changed.

[Loki]

Yeah I was looking for the model number or some kind of descriptor for the plug connector. Its difficult to try to match because there are so many different standards, and searching google for "plug connector" will find you lots of wrong answers.

I ended up using a phone jack connector which actually worked well, and since its for doing cnc, the connector can be a bit fragile.

If you have a part number or something more descriptive than "plug connector" I would still be interested in wiring it together right.

I noticed that actually, I'm quite confused about the whole deal because http://www.affordableplasmacutters.com/about makes it sound like they are designed in the US and built in China, but are now switching over to American side manufacturing, etc... anyways. They didn't have a pilot arc plasma cutter in stock a month ago, so we went with everlast, however our machine didn't come shipped with a torch head for some bizarre reason and it took almost a month to sort it out.

On the plus side the interface worked and we now have a pc to plasma cutter interface that cost less than $10.

[everlastsupport]

On the plus side the interface worked and we now have a pc to plasma cutter interface that cost less than $10.

This is the interface not the controller right?

[Loki]

Terminology crunch.

The interface is the device that makes the short between the control pins normally performed by the manual trigger. This is accomplished by using a solid state relay that has optoisolation built in . The part number is AQV252G . It cost around $4.61 from mouser I believe. The rest of it was housing and wiring for the thing.

[everlastsupport]

You had me all excited. I thought you had the controller for $10. You are talking about the remote on off for the torch.

Not sure if I would use an SSR for the remote control, I would have gone with a mechanical relay. But if it works that is great, will last for a lot longer time. I like using SSRs for AC switching with none inductive loads. But that is just me.

Post up some pictures. I would love to see what you have.

[WAYNESWORLD]

Yes, please post some pictures.
Wayne