problem with state machine

[Turillo]

Hi! I've got a VI intended to control a storage tank. I've tried to do that by creating a simple state machine that changes the value(on/off) of some valves basing on 2 conditions:

-when a certain temperature reaches a pre-set value AND its derivative is <0, the state must change from on to off,

-when some time passes the state must change from off to on.

Unfortunately I can't get this work as it never changes state (e.g if I start with on always remain on "on" and viceversa).

Could you please tell me what I'm doing wrong? I'm attaching the screenshots of the 2 states.

Thanks!

[GerdW]

duplicate post, continued here!