Float Switch Issue

[nathan_madness]

Hey, I have a float switch in my HLT that I want to control the heating element using ladder logic. I've tested and re tested everything so I know it's wired correctly, but when the float switch is activated it switches on the element for only a second or two then it shuts back off.

Has anyone else had this issue or point me in the direction of where I am going wrong?

Thanks
Nathan

[oakbarn]

Not enough Information.
How is the float switch wired?
NO or NC switch?
What is your Ladder Logic?

Pixs are good to see also.

[JonW]

Do you have "one shot" checked on your DIN?

[nathan_madness]

Hey, the float switch is wired for NO and I don't have "One Shot" enabled. Here is a image of the ladder.
Thanks
Nathan

[Joyride-Brewing]

What does OUT0 do? What is the HLT temp probe process and exit?

[nathan_madness]

"Out0" is the HLT Element

I don't have any process for it yet. I can't even get it to work in "Manual" mode.

I have found that if I don't have "Out0-4" in PID control (all in on or off) the "Out0" will come on even though it should be controlled by the "Din0" float swich. If i switch any of the Out's 1-4 into PID control the "Out0" will turn off.

[Joyride-Brewing]

Sorry, I knew OUT0 was the HLT element SSR input, I didn't know if you had a parallel process for it in the logic for the HLT temp probe, I know you can't control the same output from a process and ladder logic at the same time. Maybe try using the float switch to start a process and control your OUT to power the SSR via the HLT temp process statements without the ladder logic.

I also had a multi position rotary switch to start processes one at a time that had a high resistance short causing a major problem, so if you eliminated the float switch and used a plain toggle switch to simulate the float switch as a hard contact, it's hard to troubleshoot someone else's system from a keyboard and screen.

[JonW]

Hey, the float switch is wired for NO and I don't have "One Shot" enabled. Here is a image of the ladder.
Thanks
Nathan

Your ladder logic looks fine. Anytime Din0 closes, Out0 should turn on.

You said it is wired for NO contacts, but what are the connections it is wired to?



Edit: Forget my question above.... Your ladder logic is not working because you are running in manual mode. Manual mode disables ladder logic.

[brahn]

Just wanted to point out that the screenshot you posted is consistent with what we would expect based on your ladder logic. The manual mode process would want to turn the HLT element on, but the ladder logic is forcing it off because DIN0 is not on.

I don't have enough information to say if anything unexpected is happening in your setup, but at least the screenshot you posted is expected behavior.

[nathan_madness]

Thanks for all your help guys. So there is no way to protect my HLT element when running in "Manual" mode unless I wire the float switch inline with the element SSR? Here is a link to some more pics of my system http://forum.embeddedcc.com/viewtopic.php?f=16&t=2569.

Cheers,
Nathan