I hope somebody can help.
i have same experience with arduino and electricity
Machine runing 3 phase motor 480v. Picture is attacked.
So i upgraded manual part with 1 42 stepper motor and Arduino mega 2560.
Everything is wired properly only i have problem with USB communication when i press
footswitch (turning 3 phase motor on). important thing is:
If footswitch not touching machine,if is on floor then arduino losing communication with usb pc port.
(arduino working, only no communication and i have to reconnect usb cable)
If i remove gnd wire from arduino then no losing communication with usb port.
If i make footswitch to touching machine i don't have any problem even arduino gnd is connected.
Also i don't have problems when arduino is powered by external power supply and footswitch is on floor.
But then i don't have communication with pc and i need pc to controll arduino by my visual studio
program.
So somthing is about arduino ground.Nema steeper motor is wired on same power as machine.Only 1
phase,neutral and eart (220v). Arduino board is in plastic electric box.
Tested with 2 arduino boards and 2 pc but i get same problem.
Sorry for may english and thank you for reading a topic.
Thank you Tom.Hire is simple wiring.I will tell you what is strange.
it doesn't matter do i connect Stepper or not.
I take only arduino board (in plastic electric box) without wiring stepper driver .When i connect arduino gnd pin on machine box (made from metal ) and press footswitch, arduino losing communication with port (no restarting arduino board).
If i connect led and write simple code arduino working.Only brake communiation with pc.
But when i make footswitch touching metal of machine,everyting working without problems for ever.It is so strange.I will try tomorrow cut + and - wires from usb cable.Make like Data only cable to send and receive data and i will power arduino by external 12v power supplay.
As others have said, check the earthing of the machine first. When you know that is ok and if the problem persists then I would suggest you check carefully how the earthing of your pc is arranged.
If the pc is a laptop then the power supplies for them are often not explicitly earthed at all. If you have a CRO handy, try looking at the 'earth' connection of the machine when you start the motor. You may be surprised at just how much noise is there.
If you don't have a CRO then a DVM between the machine earth and the shell of the usb cable (disconnected from the arduino) may give you some idea of any problem there. Try low range AC settings first.
My thinking is that the noise generated in the earth circuit is coupling into the usb in common mode and overdriving the usb interface.
Let me know how you go and if the pc is a laptop and if it has an earth pin.
So much noise is there and if lift foot switch top of machine then no noise.What you think if i order bluetooth serial communication module or do you have some advice what is best way to avoid a noise.
And my laptop charger have EARTH but i think it is not so god.
Paul_KD7HB:
One phase to neutral/earth is 277 volts, not 240 volts. Sorry.
Paul
I don't understand where you get 277V from. In Aus we are supposedly 230V phase to neutral although in NSW around 250 is more common until they get the grid sorted out.
In many cases Paul trying to found mistakes.I don't want to argue with him and my english is not god.
If you know and if you wish, help.....If not....Then don't.
That is reason why i put smyle Paul you are right.
I know 1 phase,neutral,earth in Finland 130 - 140 volt
PedantEngineer thank you.I was checking all day end BINGO.
You was right.I tested wit third old hp laptop and no problems.
I will try this week with desktop Pc and inform you.
PedantEngineer:
I don't understand where you get 277V from. In Aus we are supposedly 230V phase to neutral although in NSW around 250 is more common until they get the grid sorted out.
Because a couple of weeks ago I had to replace our reflow convection oven. They run 480 VAC 3-phase. The electrician checked the voltages as a final step. Phase-to-phase was about 485 volts. Each one a couple of volts different. Also checked volts to common and they were about 280 volts with a couple of volt variation.
So, when I read the comment about the voltage being 240 volts from a 480 volts service, I knew that was wrong.
The logic ground signal/line should be considered separate from protective ground (earth). Protective ground is not designed for current transmission, else an earth leakage circuit breaker should disconnect all mains connections. This means that logic ground must be wired properly, to all parts the control circuit, separated from protective ground. If required, the control logic must be isolated from parts (motors...) connected to power supplies (mains...).
I live and learn! 480V is common enough in industrial USA. Who knew!
It seems to be a thing only in big industry. Small scale in the US is largely still 2 phase 115/230 (or any one of a thousand variations on the theme) or 3 phase 208 or 400, I'm not sure which is the more common. I suspect it depends on how "small" you define small industry.
So there it is, the reason all those relays I have designed into products over the years that had a 277V rating on the contacts; it wasn't 240/415 + 15% after all.
Within the US, 277 volt (single phase to ground, only with grounded wye distribution) is commonly used for factory floor/industrial/commerical lighting. In the day, both florescent and high pressure sodium/metal halide devices were common, now it is moving to LED for new installations. Just Google "277 volt LED lighting"
PedantEngineer:
I live and learn! 480V is common enough in industrial USA. Who knew!
It seems to be a thing only in big industry. Small scale in the US is largely still 2 phase 115/230 (or any one of a thousand variations on the theme) or 3 phase 208 or 400, I'm not sure which is the more common. I suspect it depends on how "small" you define small industry.
So there it is, the reason all those relays I have designed into products over the years that had a 277V rating on the contacts; it wasn't 240/415 + 15% after all.
PE.
We have talked for years to our land lord about getting 480 into our suites. All suites have 208 three phase, 200 amps per meter. We have 3 meters and have to use one, through a step up transformer, to get 480. He was involved in the initial development of the entire industrial area around us. All those transformers giving 208 are fed by 480. The property across the street has 480 and 208. The property on the corner has 208 and 480. Down the block, a company that cuts marble for counter tops, etc. had to run a new line under a street to a transformer to give them 480.
Don, our land lord, tried to get the building owners to put in 480 for us and a machine shop, but nothing has ever happened. Sure would make out lives easier! Too much cost!
Hey OP,
Sorry, I've been buried deep in my own project for a while and just come up for air, and read you are giving up!? Oh no! Don't do that. I would be very disappointed to think you asked for help and were trying so hard yourself and then we failed to help you.
It is curious that the operating system makes a difference but not totally surprising. If I am right (as you suggested I seem to be) about the noise issue then it is a matter of how the OS handles errors and clearly Windows doesn't do it as effectively as Ubuntu in this case. Either way, you have a noise issue that needs sorting out.
Is it possible in your project to isolate the PC using opto couplers for example? I'm thinking that the noise is likely to be far too big for an RS485 type interface and fairly high frequency as well (sharp edge signals even at low repetition rate will mean high frequency components in the spectrum). So the high CM voltage tolerance as well as the high dv/dt rating of an opto might be your best bet. There are also 'digital isolators' around that might be the ticket and they make to job sooooo much easier. Have a look at ADuM7240 and ADuM7241 for example. They might be expensive but if they prove the point then you can concentrate of a cheaper solution knowing you are working in the right direction.
I hope that helps and I'm not too late with the advice.
