Valid Arc Lost 2

Had a busy morning and finally got around to jaycar.

Turns out they dont have 5W resistors in ceramic, only wire bound, will this do?

I grabbed 270 Ohm 1W ceramic resistors as well just in case but unsure if these will suffice.

Will the 3x 270 Ohm 5W wire bound resistors be fine? I assume they do the exact same job as ceramic resistors, just in a bigger footprint.

They will do just fine.

little_sparky wrote: Will the 3x 270 Ohm 5W wire bound resistors be fine? I assume they do the exact same job as ceramic resistors, just in a bigger footprint.

Yes use these ones to handle the current.

Phew, finally at 11:13 at night I have time to upload the ini and hal files, sorry it took ages.

I still havnt had time to wire in the new resistors to test if they work but here are the files to check them out.

My only concern is any debounce or lowpass filters I have missed.

Thanks for the help thus far.

hal



ini



connections.hal

little_sparky wrote: Phew, finally at 11:13 at night I have time to upload the ini and hal files, sorry it took ages.

I still havnt had time to wire in the new resistors to test if they work but here are the files to check them out.

My only concern is any debounce or lowpass filters I have missed.

Thanks for the help thus far.

I don't run a lowpass filter on the THC, so I can't comment there.

I (and a few others) run a debounce on the arc-ok input as it's a mechanical contact. It solved a problem similar to yours on my and CBEAR's tables. I attached a modified version of your connections_hal file to add a 5ms debounce to the arc-ok input. That could essentially equate to a 0.005s added pierce delay (which I doubt anyone will notice ).

Between that, and pulling the minimum current through your relay contacts, you should have a reliable table for years to come.

Let me know if you have any questions.

snowgoer540 wrote: [I attached a modified version of your connections_hal file to add a 5ms debounce to the arc-ok input. That could essentially equate to a 0.005s added pierce delay (which I doubt anyone will notice ).

Between that, and pulling the minimum current through your relay contacts, you should have a reliable table for years to come.

Its never wise to do two things at once because you don't know what the fault was. Save this one until after you have wired in your resistors and cycled through a few attempted cuts. I personally think if it was a debouncing issue, you would have had problems well before this.

I would tend to disagree, debouncing should always be used with mechanical contacts
unless the sampling interval is slower than the longest bounce times.

quick update, wiring in the 3x 5W 270Ohm resistors didnt make any difference, also checked my PSI into the machine and had more than enough, turned it down to about 100.

Am putting in the new connections.hal code snowgoer wrote and will report back.

Did you cycle it a few times to burn off the oxidisation? Don't give up straight away...

Okay so, I think it works!

Cycled the machine through about 10 times, didn’t work.

Put snowgoers file in, didn’t work.

Went for a little walk from one end of the shop to the other wondering what the scrap metal price of a plasma cutter that I have been building for 2 years is worth.

Came back and had a thought, what if somehow the -24V isn’t supposed to come from field power on the board. So I moved it to the -24V from the DC power supply and it worked!

Makes me wonder, would it have worked without the resistors or the new code? I’m not sure but I will do a process of elimination to find out in the near future, for the minute I have some cutting to do!

Thanks heaps guys.