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Heat Generation for a Specified Time

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Hello all,

I have a model in which I have two heat sources, one of which starts at the beginning of the simulation, and the other is controlled (turned on) by a temperature probe. Is there any way to specify the duration that the second heat source is turned on for? I.E; The second heat source should kick on when its boundary probe reaches a specified temperature and then turn off after 60 seconds.

I have tried to define a tau variable that captures when the boundary probe reaches the target temperature, but unfortunately it becomes a continuously increasing value during the simulation...

Thank you for your help!

Ben

1 Reply Last Post Oct 15, 2012, 3:16 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Oct 15, 2012, 3:16 a.m. EDT
Hi

there is an example of a PID controller implementation somewhere in the model library, you need then to define your "switch" variables, i.e. limits and a time counter that starts to integrate with the turn on switch. Now remains an unknown how to reset the switch, perhaps with an if(,,,) on the limit value. If you have a fixed time the rectangle/pulse function is nice to use, as its "smoothed".

What is certainly possible is to drive all this from Matlab

--
Good luck
Ivar
Hi there is an example of a PID controller implementation somewhere in the model library, you need then to define your "switch" variables, i.e. limits and a time counter that starts to integrate with the turn on switch. Now remains an unknown how to reset the switch, perhaps with an if(,,,) on the limit value. If you have a fixed time the rectangle/pulse function is nice to use, as its "smoothed". What is certainly possible is to drive all this from Matlab -- Good luck Ivar

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