SR-Flipflop Not behaving as Expected

[SteveAtkins]

I set up a programmable logic gate to do the following:

- Stop the main circulation pump when water level in sump went down to lower level sensor (sensor 2)
- Keep the main circulation off until I manually started it by setting Maintenance 3 ON.
- Use SR-Flipflop with the SET trigger being the water level reaching sensor 2 and RESET trigger being Maintenance 3 going on
My function works perfectly until Maintenance 3 turns OFF again (either manually or due to max on time)

When Maintenance 3 turns off the main circulation stops. The logic is correctly turning the circulation pump on with the leading edge of the reset trigger (Maint 3 ON) but is then also responding to the trailing edge of the reset trigger (Maint 3 Off).

Below is a graphic of what is happening and included at the bottom is what should be happening according to the Programmable Logic manual

LowSumpTriggerFunction.jpg

[SteveAtkins]

Have resolved it.

I moved the logic further down the gate hierarchy (which I don't think had any effect) and also rearranged it to put the flipflop function after the gates that provided its input.

Previously I had the flip flop first then built up the set and reset logic in subsequent gates.

I haven't done any more testing since I got it working fully but suspect order may be important.