Hi,
Hmm, now that is sounding like more work than using code LOL
Two resistors, a capacitor and an op-amp and maybe a relay or SSR to amplify the signal to turn on the pump.
Really, is that more work than learning to code Lua?. Particularly as the code you'll have to write will probably be
(mainly) in the PLC script where all and any code needs to be fast, sleek, efficient and robust. A failing piece of code
in the PLC script can hang or crash Mach and it can be the devils own job to unwind it.
Craig