Proline_2150 plasma Arc dropping out

[SutherlandMachining]

Good morning everyone, I am working on the above machine and having some trouble. the machine has just be brought second hand and the customer is seeing problems holding an Arc. It pierces fine and cuts for about 10 mm then the arc drops with no real feed back as to why.
I have left site now but am trying to support them through this problem. I will list some of the details below

- Proline_2150
- INOVA torch height controller
- Burny_10 CNC Software
- material thickness has no bearing on results
- we did have the machine cutting on 3mm for a short while, at this time we had to set the arc volts much higher than recommended to get a result
- machine pierces moves to cut arc cut's every time pretty consistently
- we have done a chopper test
- checked leads
- cannot confirm the adequate ground stake but earth from chassis to proline unit appears to be good
- gas pressures are set to Proline recommendations
- LED's on boards are as nominal to the best of my knowledge

If anyone can help on this one I would be very grateful, Also happy to pay for successful diagnosis


Thanks

Ross Sutherland
Manager
Sutherland Machining Services Ltd
0278857620
www.Sutherlandmachiningservices.co.nz

[rodw]

Ross, I don't know your machine but at a guess, there is a poor connection or signals are affected by noise.
The E cable seems a suspect based on the manual.

When the ProLine 2150 is ordered with the integrated Inova torch height controlsystem, connect the Inova C cable between P8 on the rear of the power supply and P3 on the Inova control panel. The C cable is used to interface the plasma start, plasma hold, and machine motion signals between the Inova and the ProLine 2150. Next,connect the Inova D cable between P7 on the rear of the power supply and P2 on the Inova control panel. The Inova D cable is used to interface the cutting arc voltage and plate sensing circuit between the Inova and the ProLine 2150. Next, connect the Inova E cable between the Work terminal on the ProLine power supply and theGround lug on the Inova control panel. Note that the E cable is not a safety ground. It is part of the voltage feedback circuit used for arc voltage control. See the Inova manual for details on x/y machine, operator’s remote, and positioner interface.

Does the machine use ohmic sensing? I am aware of one new HF machine where the ohmic probe signal as being triggered spuriously by noise (the Ohmic wire is a very effective antenna). On that system, it was an error if the probe was triggered while cutting so the machine halted intermittently. It was under warranty but we thought a $15 decoupling capacitor where that wire entered the control panel would have fixed the issue. Of course manufacturers don't want to listen to advice like that from apparent amateurs!

[SutherlandMachining]

I am not sure Re: Ohmic Sensing. are you saying that there may be interference (noise) from the plasma being induced into the sensing Circuit?
I have found an error code #9 Output voltage above 185V,
Do you think a good start would be to measure the output voltage and see what it actually is ?

[rodw]

I found the email with the advice from my resident HF electronics advisor. The machine in question was using a Hypertherm Maxpro 200 and from new sometimes the machine would error out because of a spurious probe signal while cutting which most CNC controllers will treat as an error and stop cutting.

The probe wire needs to be filtered (preferably with an LC Filter) at the end of the wire as it enters the metal case containing the electronics circuit. Sound like the wire is behaving as an antenna and picking up RF from the plasma. Plasma are extremely “dirty” from an RF point of view. Something like this

Of course your machine may not use ohmic sensing and could rely on a float switch to sense the material surface.