Level Switch Program issue

Hi Guys,


I wrote a Program on Tank Over fill Protection system. There are Five Tanks/Five Rosemount 2120 Level switch inputs and One Audio Visual Alarm output.
I SET the Alarm with inputs from the Level Switches on the Tanks and RESET all with a Push Button.

Carrying out internal FAT today, I noticed that the Trigger input from the Level Switches remains TRUE so long as the switch is still in contact with the liquid and this renders my code irrelevant.

QUESTION PLEASE:
How can I achieve this? Rising edge don't seem to work here.
I'll Appreciate your supports.

You need to use a one-shot instruction.

I'm assuming the switch goes from off to on and remains on as long as the liquid is covering it. Using a one-shot will require the switch to go from off to on before it alarms again.

sparkie said:

You need to use a one-shot instruction.

I'm assuming the switch goes from off to on and remains on as long as the liquid is covering it. Using a one-shot will require the switch to go from off to on before it alarms again.

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Thanks, it worked