Running laptop next to a welder?

I received my microcontroller (CUBLOC CuSB-22R) and got it to sort of work, that is, it executes sample programs and prints things on LED display and turns relays on and off.

At some point I will have to write and debug a program to control my welder, with the CuSB inside the welder. I have a laptop that presently runs linux, perhaps I can somehow install Windows on it too so that I can run Cubloc Studio.

My question is this. Is it unsafe for a laptop to be located next to a working welder, with HF possibly turned on, open panels, etc?

Would it be a good practice to download code to the controller, disconnect laptop and take it away (to another room or some such) before starting welding? Or is it unnecessary? Would it be OK to just disconnect the serial cable so that there is no electrical connection between laptop and the welder?

I have other alternatives too:

- connect and disconnect CUSB every time I need to upload a new version, and run with it to a computer (a real hassle)

- buy a 100 ft (sic) serial extension cord and run it to a computer inside the home.

Anyone has any idea what I am even talking about?

i
Reply to
Ignoramus2833
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A few years ago, I noticed that if I activated my 250,000-volt stun gun near my computer, it would start to make a beeping noise. Pretty cool, actually.

Food for thought. ;)

Michael

Reply to
mrdarrett

Yes, be prepared for any supprises, much depends on what kind of interference your sparks amd magnetic fields produce and against what levels is your laptop immune. Any wire hanging around can act as tuned circuit and develope supprising signals with unknown results. So just beware.

Have fun

Stanislaw Slack user from Ulladulla.

Reply to
Stanislaw Flatto

Make a toslink connection. It manages 12 Mbps with plastic fibres upto 10m. Should help some.

Other than that. Strong current = magnetic fields, and magnetic fields are way harder to insulate from. Mu-metall is expensive. I suspect the hardddisc may be vurnable. So you could use a machine with networked storage to overcome this.

Reply to
pbdelete

What if I simply use a 100 ft serial cable to a computer in another room. Would that be OK?

i
Reply to
Ignoramus27153

Electricity follow the conductive path. You have to measure. It can also act as an antenna I suspect. I think optical gap is preffered.

Reply to
pbdelete

Operating a welder close to a computer will subject the computer to very strong "near field" effects. These effects are related to the fact that the very intense electric and magnetic fields produced by a welder are poorly coupled to the free space and are very highly divergent. The intensity will fall off with distance at a much higher rate than the classic

1/distance rate of plane waves, will not efficiently couple to the space around the welder and thus will not be of significant intensity at a distance of only a few feet from the welder.

More than line isolation or filtering, distance from the welder is the key parameter in terms of controlling interference from the welder.

Shielding from the locally intense electric and magnetic fields may be helpful and it is doubtful that mu-metal is required as it will only be effective at extremely low frequencies. The laptop will probably not be affected by very low frequencies unless there is a local ground loop forcing interface signal levels to extreme values.

Shielding will be cumbersome as the screen of the laptop must be visible. Perhaps a transparent conductive material such as copper screen would work.

The welder may also draw such large amplitude current spikes that the local line voltage may be suffering from low voltage ripple or high voltage surges that could affect the power supply to the laptop. In this case a laptop has a great advantage over a desktop computer in that the battery should take out most of these effects.

Hope this helps

John E. Kuslich

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Reply to
johnk55

Thanks. I think that I will simply keep laptop at least a few feet away, and will disconnect serial cable prior to start of any tests.

i
Reply to
Ignoramus27153

Probably, but I'd still unplug it for when you're doing the high current stuff.

Good Luck! Rich

Reply to
Rich Grise

The bummer is that my laptop does not have a serial port, as I discovered. :(

i
Reply to
Ignoramus27153

hardddisc

my dmm would not work right near the welder with hf starter on :-) my first dmm does not work from a high voltage spike it now just beeps flyback got that one :-0

Reply to
kidkv

Possibly. In addition to what others have mentioned, DC magnetic fields can be dangerous to the laptop. This does not result from direct induction of voltages, but shifting operating points due to the field causing failure. I lost a laptop backlight inverter due to a fridge magnet on a shelf nearby. Pushed it a little close (not touching) and it stopped lighting. The core of the backlight inverter transformer had saturated, or gotten close to it, and blown a fuse, as I later found.

Reply to
Ian Stirling

Get a USB->Serial dongle.

j
Reply to
John - KD5YI

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