Biggest of the filling skids on our site, 5069-L320ER on V33. The fill and CIP sequence is 30 steps, written by the OEM in ladder with a bit per step, 400 rungs of interlocked latches. Nobody here can follow it any more and the last change took a week.

The rewrite's landed on me and I'm normally the network and server side here, which is half of why I'm asking. Rewrite the lot in ST, or SFC, or leave it in ladder because our electricians only know ladder?

I tried an ST version of the first ten steps as a CASE on an integer and its 80 lines and I can read it fine, but one of our electricians looked at it for about a minute and walked off. So that told me something.

Which way would you go when the electricians only read ladder, because I'm not sure I'd get away with ST here?