I am a mechanical engineer delving into Arduino and need some, who am I kidding, a LOT of help…
I want to combine a bunch of shields into one board for use in a harsh manufacturing environment. I want to combine one of the Logos Electromechanical 4X4 Driver Shields(I need at least 12 high current DC switches, 16 is preferred), one of the Sparkfun BMP085 Breakout boards, and 4 of the Tautic Electronics MAX31855 Type K Thermocouple to Digital Converter - v2 boards(for 4 thermocouple inputs).
To add a level of complexity I want to put all of this into a Deutsch EEC-5X650A housing with a DT13-48PABCD-R015 header connector integrated into the custom PCB. Board size to fit into this enclosure ie 5" X 6.50" with a few keep away zones but seems like way more than what I need for space base don the size of the shield sizes I noted above.
I am completely unfamiliar with Eagle design software… Any help is greatly appreciated!
When you say “harsh” do you mean physically or electrically harsh or both?
In either case, I would not use an unmodified Arduino in any kind of industrial environment. Learning Eagle will be the least of your concerns here.
First concern is power: where is it coming from? Are you assured of having a nice, clean 5 or 12V supply in all cases or does it need additional filtering. Even if you do, what happens if a tired technician connects it backwards?
Then let’s think about I/O. Sure you may connect a thermocouple to that input, but what faults can happen to the thermocouple wiring? Could the probe be mounted on a machine that has a ground that’s 20V above the Arduino ground?
Likewise, if the load on one of your DC switches is accidentally shorted, what protects the drivers? Can a fault there take out the entire system, so it’s down for the rest of the day or until a spare unit is brought in?
Not trying to be a negative nanny, but there is a reason that PLCs are hardened as much as they are: the manufacturers have seen just about every failure mode possible and attempt to protect against it.
What I am doing is aking a 4 motor vacuum hold down table for my ShopBot Desktop CNC. Everything will be in an enclosure of some sort.
So far I have a Mean Well RT-125D power supply that outputs 5VDC(8A), 24VDC(3A), and 12VDC(2A). I can get a different one if needed. The only technician that will be working on it will be myself or my dad… It’s not a full time business just a hobby.
The I/O will mostly be in stainless piping for vacuum which will have ground lugs all over it to dissipate any static caused by the vacuum as well. Anything I can do to protect the thermocouples and/or pressure sensors would be great.
If the system had to go or did go down it wouldn’t be that big of a deal. Commercial vacuum systems are extremely pricey and we are doign the same thing for a fraction of the cost with much more control.
We do have a AB Micrologix 1100 but would rather give the Arduino a go before we go to a PLC. Let me know your thoughts.
First question I’d ask is why are you combining the shields? Do you plan to make it into a commercial product? Otherwise why not just keep the existing shields you have? You can save a bit of cash: instead of 4 thermocouple shields, it should be possible to use just one with a 4x1 multiplexer.
There’s no problem with what you are trying to do, but when I heard “harsh manufacturing environment” and “Arduino” my ears perked up. Are you just concerned about learning how to use Eagle?
I totally understand and appreciate the thoroughness.
The reason for the custom board is two things, I have a nice enclosure I want to package things into and I’ve never been through the design and development of a PCB so it is also a learning opportunity for me as well…
