SR-Flipflop not Flopping Properly - Programmable Logic

[Steve Atkins]

I have set up programmable logic for the following:
1. When water level drops to lower sensor (possibly due to RODI supply running out or ATO pump failure) the main circulation will turn off.
2. A manual reset is required to start main circulation again. This is because when the main circulation pump turns off some water will flow back and lift the sump water level above the bottom sensor and the pump must not turn back on because of this.
3. I have used the “Return Pump” level function with level sensor 2 to trigger the event
4. I have used Maintenance 3 as the manual action to start the return pump again
5. I have used SR-Flipflop to control the operation.

The Results
• Shutting down the pump when the water level reaches the lower sensor works
• The pump remaining off until manually reset works
• The pump starting again after I select Maintenance 3 works.

HOWEVER – when Maint 3 is turned off (either manually or via max on time timer) the main circulation pump turns off again.
It appears that the Reset trigger trailing edge is having an effect but according to the manual it should be ignored.

What am I missing?

Settings are below, along with a graphical representation of what is happening.
Note that the socket actually uses Programmable Logic 1 INVERTED so the socket picture is slightly wrong (socket setup in picture was for picture purposes only)

Unit is Profilux 3.1N running 6.14 firmware.

 

[Steve Atkins]

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 the order in which you define gates may be important.