This happens when the system timestep has just shortened, or “downstepped.” E+ has a zone timestep and a system timestep. Here, it has first run a system timestep of 10 minutes (from 8:10 to 8:20), then later decided it should be shorter and repeated a system timestep that starts at 8:10 (from 8:10 to 8:13). Because of this and other iteration/timing issues, you will have a hard time counting up time entirely on your own. So the EMS runtime language includes some built-in variables for time-related data, see Table 2 in the EMS application guide. The built-in variable SystemTimeStep will be useful for your application (e.g. it will have changed from 10/60 to probably 3.3333/60 in your example below). Combine this with the output processing that happens with an EnergyManagementSystem:OutputVariable that is summed and you should be able to get time counted up correctly. Brent
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of dgerome06
Sent: Tuesday, August 02, 2011 9:29 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] SystemTimeStep in EMS
Hello,
something strange happens during my simulation in which i'm using EMS for calculations.
I would like to count the duration time when my system is on. But i have counted more hours (2400) than the total hours in the simulation (2200). I have checked the .edd file where i have seen :
FONCTIONNEMENT_GROUPE_FROID,Line 1,SET TMP=PLR,0.157648, Occurrence info=TEST SIMU 2MOIS, 08/14 08:10 - 08:20
...
...
...
FONCTIONNEMENT_GROUPE_FROID,Line 1,SET TMP=PLR,0.163321, Occurrence info=TEST SIMU 2MOIS, 08/14 08:10 - 08:13
So the simulation counted twice the period 8:10 - 8:13.
Does someone know where this problem come from??
Thanks
Jerome
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