Migration from VB6/RSLogix to C#/NET.ABLINK

[BLees 0]

The PLC controlling our refrigeration plant is a PLC 5/40. Years ago I wrote a VB6 GUI program using INGEAR's ABCTL driver;

It still works perfectly under XP, but, needing Windows 10, I had to get their NET.ABLINK driver and rewrite in C# (at which I'm no guru).

The program's basic function is to make one read of 5 ints, one read of 2 ints, three reads of 8 bits of DI, three reads of 8 bits of DO, assigning the read values to screen elements after each read. These calls are in a Timer event that allows plenty of time for the I/O. There are thread.sleep calls between the reads as well, to give them more than enough time to complete. (I also put some test code nonsense in Button events).

My C# program works initially, but after 1 to 10 minutes it begins to spit error messages about startIndex, which I can't even find in my solution. If I let it run it it throws an error for incorrect data types, as though the PLC is responding to an int read with bit data.

I attach a screen shot of the failure, as well as the form code (to open in Notepad or code editor). Thanks for any tips you can provide!

RefrigForm.cs

RefrigForm.cs.txt

RefrigForm.cs

[BobLfoot 302]

PLC 5/40 and serial comms and only 250 ms between read calls.

I'd try a 60,000 values in the thread.sleep command and see if things behave differently. {One read per minute to start and if that works drop down. }

Just a quick off the cuff first idea!

[pturmel 160]

On 9/19/2023 at 3:33 PM, BLees said:

error messages about startIndex, which I can't even find in my solution

That strikes me as a likely threading error.  I'm not familiar with those libraries (haven't touched .Net in ages), but that kind of error rings a bell in the back of my head.  See if the docs are annotated with multithreading limitations or best practices.  (You generally cannot interact with GUI components from a non-gui thread in most platforms.)