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Re: [TRNSYS-users] Error Message 441 after using equation



Ole,
I'm not sure if anyone responded to you about this but it is a classic problem in controls. It is not just a TRNSYS problem. When your zone temperature is greater than 24 then the cooling turns on and brings the zone temperature back to 24C at which point your controller realizes that cooling should be off because the zone temperature is not greater than 24. Cooling is turned off and the zone temperature rises above 24C again. You need to use a controller that has a deadband (cool to 23.5C and then turn off. Don't start cooling until zone temperature reaches 24.5C - or something like that.

What makes this a little complicated in TRNSYS is that you're mixing two ways of doing heating and cooling (energy rate control and temperature level control). I would recommend that you go though the tutorial called "Temperature Level Control from Energy Rate Control" that can be downloaded from http://sel.me.wisc.edu/trnsys/downloads/tutorials_and_examples/tutex17.htm)
Best,
 David





On 1/30/2015 03:36, Ole Nienaber wrote:
Dear All,

I'm modelling a building zone with TRNBuild and I'm controlling my heat and cooling demand by the Heat and Cooling Type Manager. It worked when I use a simple schedule for my Cooling Type Manager to control the temperature. But then I tried to use an input instead of the schedule. In the deck, I implemented an equation which should give back 1 or 0 while using the mathematical function GT(T_zone, 24), so that I get back a 1, when my Zonetemperature increases over 24°C and 0 otherwise to regulate my cooling. But when I tried to calculate it, I received this message like 30 times

TRNSYS Message 441 : The inputs to the listed units have not converged at this timestep. The values at the last iteration will be used and the simulation will proceed. Reported information : UNITS: 56

and then this one:

TRNSYS Message 450 : The maximum number of warnings allowed per simulation has been exceeded. Please fix these warnings or increase the limit on the number of warnings allowed per simulation (LIMITS command) Reported information : Not available

Can anyone help me with this problem?

Thank you so much in advance,

Greetings,
Ole Nienaber
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