Back in the early-mid 80s
I worked in a large hospital laundry and the two work horse machines were 450lb divided chamber washers - don't remember the name of the machine manufactuer but I remember that on the left side of the machines was a small window and inside was a metal mesh covered drum with a row of contact arms and to program the machine wash, rinse, extract times/sequence you would take a laminated sheet that was outlined with rows that matched the contact arm postions and cut out a length of each row and that would determine the length of time each action
would run. You would have, for example - fill, pre-wash, dispense initial detergent, drain, extract, fill, main wash, dispense detergent, drain, extract, 1st rinse, drain, 2nd rinse, drain, extract, final rinse, dispense sour/softener, drain, final extract - any number of combinations. The cut out sections of the program sheet would allow the contact arms to contact the metal mesh on the drum completing the circuit and resulting in a particular action being completed in the cycle.
I was interesting to run those big behemoth machines and we used alkaline detergents that were neuteralized during the final rinse with the softener/sour mix.