ALPHABETIC REFERENCE EXCEL CARE CONTROL ICONS
74-5577–33 (US) 180
EN2B-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 protection
function outside of EOH. When the outdoor air temperature is less than or equal to
2 °C, the table sets a constant room temperature setpoint (for example 10 °C. The
value of the constant is the X2 input of the SWI icon.
Frost protection applies only during the cool-down phase because EOH3 demands a
0 °C flow temperature during this time and the flow temperature setpoint of the
application 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 use
At optimum start, Start (YD2) goes to logic 1 and returns to logic 0 at occupancy
start time.
At optimum stop, Stop (YD3) goes to logic 1 and remains at this value until optimum
start occurs (next day or later).
Optimum Start
with 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 a
corresponding low flow temperature setpoint.
Medium load—switch ON time is occupancy start minus a value between P1 and
P5:
Both the TOat (outside air temperature) and TRm (room temperature) have an effect
on the switch-on time. The statement calculates the flow temperature setpoint from
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