Snuggly's Plasma Build

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15 Oct 2018 22:29 #118853 by snugglylovemuffin
In an effort to save the newcomer, I'm starting this new thread so they can follow progress.

I have a 5x10 plasma table running linuxcnc 2.8. My controller is a Mesa 7i96 w/ dm542a stepper drivers powering Nema 23's. The THC is a Proma 150.

My current plasma cutter is a HF start Eastwood Versacut40; it will be among the first things to be upgraded. Because the machine is HF start, I've gone to great effort to ground the machine including running a ground wire to my shop's earth.

Now that the controller is setup and the machine files are largely complete, it's time to integrate the THC. The Toma files from Proma were developed for Parallel Port and were too difficult to modify for the Ethernet board. Grotius had/had been developing a plasma/laser branch that looks promising; however at this stage the development is too new for a machine to reliably run for a noob as myself. For posterity, here is the link is to the Grotius development thread: forum.linuxcnc.org/plasma-laser/34916-us...lasma-thread?start=0

For the reasons above, I will be trying to use THCUD (THC specific to Mesa) : linuxcnc.org/docs/html/man/man9/thcud.9.html

I've had difficulty in the past implementing THCUD, I hope that this thread will hope those struggling with the software end of the plasma cutter build!
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16 Oct 2018 04:18 #118862 by islander261
Replied by islander261 on topic Snuggly's Plasma Build
Ok, good start.

Do you have your basic X,Y,Z motion working with all desired homing and limits? Are you running 2.8 pre because you have a dual drive gantry machine? Do you have your probing for material surface working ( G code subroutine or inline code)? What input pins do you have your Arc Ok, Down and Up signals connected to? Does your Arc Ok signal work correctly when you manually trigger the torch? Have tried to use Halscope to monitor your input pins yet? To sound like a broken record .ini and .hal files are a big help when trying to solve configuration problems.

John

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16 Oct 2018 23:19 - 16 Oct 2018 23:23 #118909 by snugglylovemuffin
I am able to jog the machine but I have some errors on my limit switches that pop up. I have the switches setup as normally closed so I'll have to find a way to make sure that the software shows a low level trigger

I am using 2.8 because I have a dual drive gantry.

I do have a float switch, however I've not been able to verify that it works.

Pinouts for the THC are:
Input #7 = float switch
Input #8 = arc ok
Input #9 = down
Input #10 = up

I'm not familiar with halscope yet, it's something I'm working on figuring out. I'll post my THCUD build here soon when I'm done with it.
Last edit: 16 Oct 2018 23:23 by snugglylovemuffin.

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17 Oct 2018 01:20 #118917 by snugglylovemuffin
Just a bit of wiring practice and question about specific components. Obviously question marks will show what I don't quite understand how to wire up. I'm not running an encoder on my Z axis, so I think a few of these commands are superfluous for my application.

WILL MY PROMA WORK ON HF START?

THCUD connections found @: linuxcnc.org/docs/ja/html/man/man9/thcud.9.html

thcud.torch-up bit in = pin 10 (hm2_7i96.0.gpio.010.in)

thcud.torch-down bit in = pin 9

thcud.current-vel float in = Connect to motion.current-vel ????????????????

thcud.requested-vel float in = Connect to motion.requested-vel ??Float switch (pin 7)??

thcud.torch-on bit in= Connect to motion.spindle-on ?????????

thcud.arc-ok bit in = pin 8

thcud.enable bit in = Enable the THC, if not enabled Z position is passed through ?????????

thcud.z-pos-in float in = Z Motor Position Command in from axis.n.motor-pos-cmd ?????????

thcud.z-pos-out float out = Z Motor Position Command Out

thcud.z-fb-out float out = Z Position Feedback to Axis

thcud.cur-offset float out = The Current Offset

thcud.vel-status bit out = When the THC thinks we are at requested speed

thcud.removing-offset bit out = Pin for testing

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17 Oct 2018 09:24 #118935 by tommylight
Replied by tommylight on topic Snuggly's Plasma Build

WILL MY PROMA WORK ON HF START?


Yes, it will.
If you have to open plasma to get the voltage for it ( in case your plasma does not have a connector with the voltage divider inside ), have a look at this before you attempt to wire it yourself.

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17 Oct 2018 14:41 #118942 by islander261
Replied by islander261 on topic Snuggly's Plasma Build
Ok, I've never tried to use this hardware or configuration but this is where I would start. If you haven't figured out using Halscope at least use Halmeter to verify that all your connections work as desired. Read about the problems with motion.requested-vel as at some point in the future you may wish to change how the component works, this is not a problem when working out basic configuration and cutting.

John

[Just a bit of wiring practice and question about specific components. Obviously question marks will show what I don't quite understand how to wire up. I'm not running an encoder on my Z axis, so I think a few of these commands are superfluous for my application.

WILL MY PROMA WORK ON HF START? YES

THCUD connections found @: linuxcnc.org/docs/ja/html/man/man9/thcud.9.html YES

thcud.torch-up bit in = pin 10 (hm2_7i96.0.gpio.010.in) YES

thcud.torch-down bit in = pin 9 YES

thcud.current-vel float in = Connect to motion.current-vel ???????????????? YES

thcud.requested-vel float in = Connect to motion.requested-vel ?? YES

Float switch (pin 7)?? = motion.probe−input

thcud.torch-on bit in= Connect to motion.spindle-on ????????? Usually

thcud.arc-ok bit in = pin 8 YES

thcud.enable bit in = Enable the THC, if not enabled Z position is passed through ?????????YES

thcud.z-pos-in float in = Z Motor Position Command in from axis.n.motor-pos-cmd ?????????YES

thcud.z-pos-out float out = Z Motor Position Command Out pid.z.command

thcud.z-fb-out float out = Z Position Feedback to Axis YES

thcud.cur-offset float out = The Current Offset

thcud.vel-status bit out = When the THC thinks we are at requested speed

thcud.removing-offset bit out = Pin for testing
/quote]

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17 Oct 2018 21:00 #118957 by snugglylovemuffin
@Tommylight - I have my Proma 150 wired up as Proma directed; negative to the torch, positive to work clamp. I've done all the wiring internally on the plasma cutter to reduce wire length and HF interference.

@Islander261 - I have no clue how to deal with the portions of the code that have question marks next to them. I don't even know if all these are supposed to go into the machine HAL. I am assuming as much, but more complete instructions are necessary for my skill level.

Just a quick peek inside my (grounded) control box
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17 Oct 2018 21:15 #118958 by tommylight
Replied by tommylight on topic Snuggly's Plasma Build
Use a shielded cable from control box to the Proma THC, grounded only on the control box side.
Use a simple relay for the probe switch, powered from the same power supply as the drives ( assuming you are using 24V ), or if you do have a 5V one. The probe switch should just turn on that relay, nothing else, the NO side of the relay should be wired to the input of your mesa card. That will eliminate all the interference from the cable going to probe switch.
As a side note, i refrain from putting the Proma THC anywhere near the plasma, i use double shielded cable to wire the output voltage wires to the proma. I am fully aware that if those two wires come near each other all hell will break loose the instance the torch is fired.
I would advise to move the voltage cables from the output terminals and rewire them as near as possible to the capacitors that are used to protect the rectifier inside the plasma. That will help a lot in avoiding interference.

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18 Oct 2018 03:06 - 18 Oct 2018 03:10 #118973 by islander261
Replied by islander261 on topic Snuggly's Plasma Build
Ok

You need to do something like this to connect the hal component pins together:

net thc-connect-current-vel motion.current-vel thcud.current-vel

or the way I find easier to follow

net thc-connect-current-vel <= motion.current-vel
net thc-connect-current-vel => thcud.current-vel

more details here:
linuxcnc.org/docs/devel/html/hal/basic-hal.html#_net

Use halmeter or halscope to test operation.

John
Last edit: 18 Oct 2018 03:10 by islander261. Reason: Added testing.

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18 Oct 2018 04:15 #118978 by snugglylovemuffin
@Tommylight
I'll swap over the proma to the controller box and run a shielded cable to it. I'll see what I can do about adjusting the mounting points of the the voltage cables for the thc, it's a pretty dense unit and it was pretty difficult to get them where they are currently.
My float switch is normally open and I have my relay setup (inside the shielded controller box) as normally open, with pins 13(-) and 14(+) triggering the relay. That would be => hm2_7i96.0.ssr.0.out-00

@Islander261
I think the problem I'm having is understanding the actual inputs of these individual components. I'm going to have to read that source and see if I can make heads or tails of this code.
The following user(s) said Thank You: tommylight

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