ALPHABETIC REFERENCE EXCEL CARE CONTROL ICONS74-5577–33 (US) 180EN2B-0184 GE51 R0518 (Europe)EOH3 Operation Example 1 The following schematic diagram illustrates the usage of the EOH3 statement.A switching table implements an outdoor air temperature-dependent frost protectionfunction outside of EOH. When the outdoor air temperature is less than or equal to2 °C, the table sets a constant room temperature setpoint (for example 10 °C. Thevalue of the constant is the X2 input of the SWI icon.Frost protection applies only during the cool-down phase because EOH3 demands a0 °C flow temperature during this time and the flow temperature setpoint of theapplication program that is equipped with frost protection is overwritten.The following flowchart illustrates the logic decisions of this example.EOH3 Operation Example 2 The following diagram shows another example of EOH3 useAt optimum start, Start (YD2) goes to logic 1 and returns to logic 0 at occupancystart time.At optimum stop, Stop (YD3) goes to logic 1 and remains at this value until optimumstart occurs (next day or later).Optimum Startwith a Room Sensor Switch ON time depends on the load on the system:Light load — switch ON time is occupancy start (P1 minimum preheat time) with acorresponding low flow temperature setpoint.Medium load—switch ON time is occupancy start minus a value between P1 andP5:Both the TOat (outside air temperature) and TRm (room temperature) have an effecton the switch-on time. The statement calculates the flow temperature setpoint fromP1P5 Occupancyminimumpre-heatpre-heat at0°C
