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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
4 Acquisition of measured values
27.05.2004
4
Acquisition of measured values
4.1 General
In the event of a faulty sensor, the RVD230 always attempts to maintain the required
comfort level, if necessary at the expense of certain heat losses. This will not cause any
damage.
In the case of severe faults, which make it impossible for the RVD230 to perform its
control functions, an error message will be generated. The controller displays this as
Er
(Error).
4.2
Flow temperature (B1, B12)
4.2.1
Types of sensors
Suitable are all types of temperature sensors from Siemens with a sensing element LG-
Ni 1000. The following types are presently available:
•
Strap-on temperature sensor QAD22
•
Immersion temperature sensors QAE2…
When the RVD230 is used as a primary controller (all plant types 5–x and 6–x as well
as 7–2), the measured value of flow sensor B1 is passed on and distributed via LPB.
4.2.2 Handling
faults
A flow temperature sensor with a short-circuit or open-circuit always triggers an error
message, irrespective of the type of plant. If that occurs, the heating circuit pump will be
activated and the primary mixing valve driven to the fully closed position in the case of
a mixing circuit, and the heating circuit pump will be deactivated in the case of a pump
circuit.
In all cases, an error message will be generated. This means: The controller’s LCD
displays
Er
.
When querying the flow temperature on the QAW70 room unit (if present), its display
shows --- if there is a short-circuit or open-circuit.
4.3
Outside temperature (B9)
4.3.1
Types of sensors
The following types of sensors can be used:
•
Outside sensor QAC22 with a sensing element LG-Ni 1000
•
Outside sensor QAC32 with a sensing element NTC 575, for connection to terminal B9
The controller automatically identifies the type of sensor used.
The sensing range is –50…+50 °C.
The outside temperature can also be acquired via LPB (refer to subsection 21.2.4
"Outside temperature source").
4.3.2 Handling
faults
If there is a short-circuit or open-circuit in the measuring circuit of outside sensor
QAC22 or QAC32, the controller will respond as follows:
Note
