Arduino for "serious" motor control?

[Skogsgurra]

I need to replace a few firing units for thyristor control with something newer and better.

These drives are running in a ten-thousand-dollar-per-hour-potential-loss application and I would not like to see any EMI issues ruining the system.

When I compare the old analogue system to the Arduino board, I feel quite confident that there shouldn't be any problems at all. I have also compared the Siemens LOGO! board and that board ought to have a few problems in an industrial environment. But it seems to work quite well - which surprises me.

The Arduino boards, again, are sturdier with shorter traces and better gnd plane etcetera. So it should not cause any problems. But the problem is that I haven't been able to verify that it actually is as good EMI-wise as I think it is. Anyone out there with positive or negative experience?

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Sorry Gunnar, but I always roll my own and have never really used Ardunos much. Something about the name grates on me. :]

I can also agree that a lot of thyristor firing circuits are dang archaic and could use improvement. If after examination you feel Arduno a likely candidate why not add all the classic installation mitigations and give them a try?

e.g.
Maybe box them in metal
Add filters
filter the power with extreme prodigious
sheilded twisted pairs where applicable
etc etc. YOU certainly know the drill.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

Thanks for the moral support, Keith!

There's one psychologic reason for a metal box - it hides the ugly truth from the user.

I have already replaced firing units in other systems, and it works well. The gating pulses are now even and exact. Before, they were uneven (+/-4 to 7 degrees variation) and that caused ripple in the armature current. But, if anything goes wrong in this system - I guess that the customer won't be his usual friendly himself. I have planned to make a quick swap-back possible. I keep the old stuff and put in multi-pole connectors so they can get back to the "inferior" system if they don't trust my SUPERIOR system

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[ScottyUK]

There's one psychologic reason for a metal box - it hides the ugly truth from the user.

That's what potting compound is for!

 

[itsmoked]

Oh, nice Gunnar.
What are you doing for syncing the Arduinos to, what, the power line?

Are all your prior endeavors motors or were any heating?

The customer should have some wee bit of humor if you're actually improving their system. Everyone usually realizes that the road up to Improvement often has a few bumps on it. Having a retreat planned is certainly the conservative ideal I'd try to go with..

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

There's more to it than that, Keith. It is about this giant company and their need to have "respectable" suppliers that use "respectable" components in their designs.

The fact that they even approached our mom&pop operation to ask for help is surprising and we do not need or want a discussion about our ability to design controller boards (which we have made for a long time, our first MCU was an i4004). So instead, we will make custom boards with the necessary terminals, power interface, analogue circuitry etcetera and drop in an "industry standard" processor board instead of using our standard MCU.

The Arduino seems to be used everywhere now, and I think that it is accepted in many industries. At least, that is what it looks like.

I think that my question was more in the direction: Is the Arduino "respectable enough" to be used in "respectable" organizations?

It is all about respect, I think.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[3DDave]

Don't mention Ardiuno - say it's an Atmel microcontroller, which it is.

For other followers of the thread, the main 'Arduino' part is the software which is just compiled into Atmel microcode/machine language. The main competitor is PIC, which is used in the controller for my home highish efficiency furnace. I think that some PICs are better armored than the Atmel processors used in the Arduino community, but they are both used in industrial applications as well as for hobby use. But the armor can be applied externally to electrically protect the chip and even the PIC won't take 110 volts straight on. If you've been making controller boards this is not news to you.

 

[itsmoked]

Actually you can hook 240V to PIC pins.

They have fairly robust protection diodes and if you limit the current with a series resistor to prevent their overheating, it works fine. Of course, you do have to consider the isolation issues.

Keith Cress
kcress -

http://www.flaminsystems.com