thatcadguy wrote:I (like many others) want to use the RPi3 (or any of them really) in an industrial automation environment. I see that there are a lot of hardware projects out there along these lines (UniPi, etc.) but so far none that I've seen are really up to the task. Most of them have analog voltage I/O (not 4-20mA current), and only 1-2 of each (need much more, like 4+ of each). Some of them don't have RS485 serial ports either (need this for Modbus RTU), or Ethernet ports (kind of pointless without this).
I don't care about ladder logic or IEC 61131-3 languages, just usable, proper I/O. Thanks for any responses.
Using the Pi in a industrial application is a very tall order. To compete against the PLC sequencer
Using Ladder logic, Production lines need fast repair , with off the shelf spares , and easy programming
In your programming you must have a high safety factor , All isolating must be don in open loop Manual.
Easy fault finding , and program checking is a must AND ALL PROGRAMING MUST BE FAIL TO SAFE
The PLC will integrate with all other sensors and MIcrocontrollers signals , 4/20ma & 0/10v are common
Industrial sensor signals to interface with the PLC in/put modules.
One last point ,a industrial environment is a very noisy( electrical) place, So a very high noise rejection
System is needed, The PLC is well suited to this