what tools (if any) could I use to program a logic control scheme graphically

Hi, Mike Francis, new member.

I've had a long career in Automation, and Process Controls, so have been using PLC's (Programmable Logic Controllers) for many years.
Now that a PC (in the form of the Raspberry Pi) costs less than a good bottle of wine, it occurred to me that Excel - with it's Math and Logic capabilities - could well be used for real-time, real-world control. I/O (Inputs/Outputs) is available for PC based platforms from Opto 22 (Digital / Analog and Bus based).

However, Excel would do a lousy job in the area of programming the logic - PLC's tend to use Ladder Logic, or Flowchart Based, or GRAFCET based languages. Ladder logic is familiar to Electrical Engineers, as it emulates (in its very basic form) relay logic. That graphical representation makes a PLC very easy to program.

So.... what tools (if any) could I use to program a logic control scheme graphically, that could then be 'compiled' in to a format that Excel could execute in real time?

And what tools are available for Excel to communicate with real world I/O?

And before anyone says 'Why?' (because I know someone will), this is purely a out of curiosity.

Thanks !

Excel's VBA ties directly into Window's COM, you can make a DLL, register it(or not) in Windows, and then reference it in the VBA project with events and all. That's likely going to be as close to the bare-metal IO as you're going to get with VBA.