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Siemens Building Technologies
HVAC Products
At the limit value, the heating curve runs horizontally. This means that the flow tem-
perature setpoint cannot fall below the minimum value.
This function can be deactivated (entry of --- on operating line 86).
13.6
External heat demand at input H5
Heat demand signals can be fed to the RVD240 via digital input H5. When there is a
demand for heat, the contact closes.
For the extent of the external heat demand, a fixed value is used. This value is to be
entered on operating line 97 as the setpoint in °C. Control is performed according to the
temperature acquired with flow sensor B1.
• Plant types 1–x: control of heating circuit pump of heating circuit 1. It is thus possible
to provide manual remote control of the controller setpoint for heating circuit 1, for
example
• Plant types 2–x, 3–x and 4–x: Control of the heat converter's 2-port valve
The function can be deactivated by entering --- .
On operating line 88, it is possible to select whether the external heat demand has ab-
solute priority (setting 0) or whether a maximum selection is to be made between the
external and the internal heat demand (setting 1).
13.7 External heat demand at input U1
Heat demand signals can be fed to the controller via the DC 0...10 V voltage input U1.
The temperature value of the heat demand signal, which corresponds to DC 10 V, is to
be set on operating line 89. This request always acts on the flow temperature setpoint
(B1).
On operating line 88, it is possible to select whether the external heat demand has ab-
solute priority (setting 0) or whether a maximum selection is to be made between the
external and the internal heat demand (setting 1).
Voltage signal:
Voltage
Temperature when operat-
ing line 89 = 80 °C
DC 0 V
0 °C
DC 5 V
40 °C
DC 10 V
80 °C
The controller considers signals below DC 0.4 V as no heat demand signals.
Basic documentation RVD240
13 Function block Valve actuator of heat converter
Temperature when operat-
ing line 89 = 130 °C
0 °C
65 °C
130 °C
55/126
CE1P2384en
27.05.2004
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