I forgot to mention that the bender in the video isn't the exact one, it's the same style but we have a different controller on it and no SICK safety sensor. Link to the controller we have on it now.http://www.currenttech.com/cab2pines.htm
A transistor array like the ULN2803 is like a "transistor bank".
Thanks for the info on the array this should come in useful.
The encoder it self is mounted directly on the pivot point on the arm, so it never actually makes it more than 3/4 of a revolution and that's in at least 3-4 seconds. So maybe 900 counts per second.
I haven't done a lot of research into it yet but I'm thinking what I read on count loss had to do more with the high RPM than anything else. I'll have to do some testing.
Just for reference
If it has solid state relays then they are optoisolated already.. Can't you just control them directly with Arduino?? Why the transistors?
It currently has a rack of opto 22 G4 OAC5 for the outputs and G4 IAC5 for the inputs they all mount to an interface board similar to the one I linked below, the specs are in the linkshttp://www.opto22.com/site/pr_details.aspx?cid=4&item=G4OAC5http://www.opto22.com/site/pr_details.aspx?cid=4&item=G4IAC5http://www.opto22.com/site/pr_details.aspx?cid=4&item=G4PB16H
I could be wrong but even at 5 volts I didn't think the small power supply would be able to handle the current needed to turn them on or off. If I am wrong that would be nice to take that out of the equation.
Getting inputs from sensors/switches on the machine, that's a longish cable run in a noisy environment, I would not run Arduino inputs directly. Maybe isolate with opto couplers or at least harden them with a series resistor and clamping diodes.
The two safety mechanisms (SICK and palm buttons), try not to implement that functionality with the Arduino but rather leave them as is. I'm not sure how OH&S will view an non-certified program handling these functions. I'd hate the thing to fire up at the wrong time because your code has & instead of &&.
As you've read the input are isolated the only inputs that I was contemplating on wiring directly would be the selector switches on the control panel.
We usually have a safety mat connected to a safety relay and the hand palms go throw another relay with timing logic. This make sure the operator can't tape one of the buttons down and try to operate it.
Both of these would be separate from the arduino. The mat cuts the power directly to the clamping cylinders and hand palms I believe go to an opto input. Ill have to check that last one.
I have some parts coming and need to gather the rest from the bender. Thanks for all the posts and advice.