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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
14 Function block Valve actuator heat converter / primary controller
27.05.2004
14.5 Minimum limitation of the flow temperature
The minimum limit value is to be set on operating line 86. The setting range for the
minimum limit value lies between 8 °C and the maximum limit value (setting on operat-
ing line 85).
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).
14.6 External heat demand at input H5
Heat demand signals can be fed to the RVD230 via digital input H5. When there is a
demand for heat, the contact closes. This facilitates manual remote control of the con-
trolled setpoint, for instance.
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 executed according to the
temperature acquired with flow sensor B1; the controlled actuating device is Y1.
The function can be deactivated by entering --- .
On operating line 88, it is possible to select whether the external heat demand has
absolute priority (setting 0) or whether a maximum selection must be made between
the external and the internal heat demand (setting 1).
When contact H5 is closed, the controller’s response is as follows, depending on the
type of plant:
Plant type Effect on control
Current operating mode
button on the controller
0–x None*
–
1–x
Control of heating circuit
Flashing
2–x
Control of common flow
Steady on
3–x
Control of common flow
Steady on
5–x Precontrol
Steady
on
6–x Precontrol
Steady
on
7–2 Precontrol
Steady
on
8–4
Reception of heat demand signal not possible –
* Plant types for d.h.w. heating only
If the RVD230 is configured as a primary controller (plant types 5–x, 6–x and 7–2), it
receives the heat demand signals from the consumers via LPB. For detailed informa-
tion, refer to chapter 13 “Precontrol".
14.7 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). It can be selected on operating line 88 whether the external heat demand has
absolute priority (input 0) or whether a maximum selection is to be made between ex-
ternal and internal heat demand (input 1).
Voltage signal:
