Libraries for Building Automation Function Block ... - Wago

Start/Stop Optimization (FbStartStopOptimization)Example: navigation of level 3.tStartLowTemperature = t#50m min/KtStartHighTemperature = t#10m min/KrOutsideTemperature = 0°CrActualValue = 18°CrReferenceValue = 20°CFor example, a start time of 30 min. is yielded from the characteristic curve (Fig. 1) atan outside temperature of 0°C.==> Start time = (20 °C – 18 °C) * 30Start time [min / °C]min = 60 min°C.tStartLowTemperaturee.g. 30 min/°C.tStartHighTemperature-10 °C 0 °C ...+10 °CFig.1: Start time in relation to the outside temperatureOutside temperature[°C]By starting up the heating installation on time, the required reference temperaturecan be reached at the beginning of the service period. If the remaining time until theservice period starts is smaller than the calculated start time, the "xHeating" and"xOptimization" outputs are switched to TRUE (see Fig. 2).dtActualTimeSwitchingOff*On*Calculatedstart timeServiceTimeFig. 2: Start-up time in relation with the calculated start timeThe "xOptimization“ output signal is reset to FALSE when the required referencetemperature, minus the ".rVariation" tolerance, is reached, or when the "normal"service period begins. This shows that the start time optimization is finished.Ideally, the reference temperature is reached when the service period begins. If theroom temperature is reached too early or too late, the characteristic curve can beadjusted automatically by shifting the grid points. This ensures that the thermalcharacteristics of the building are identified by the function block.Automatic correction of the grid points will not be performed if the installation isswitched off for more than 20 hours (see Holiday Effect).Subject to design changes WAGO Kontakttechnik GmbH & Co. KG P:O. box 2880 • D-32385 Minden Phone: 05 71 / 8 87-0 E-Mail: info@wago.comCopyright © 2013 Hansastr. 27 • D-32423 Minden Fax.: +49 (0) 5 71 / 8 87-169 Web: http://www.wago.com16