Siemens RVD110 - 4 Acquisition of the Measured Values; General; Flow Temperature (B1); Types of Sensors

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Siemens Building Technologies Basic Documentation RVD110, RVD130 CE1P2381E
HVAC Products 4 Acquisition of the measured values 27.05.2004
4 Acquisition of the measured values
4.1 General
In the event of a faulty sensor, the RVD110 / RVD130 always attempt to maintain the
required comfort level, even at the expense of certain heat losses, which will not cause
any damage however.
In the case of severe faults that make it impossible for the RVD110 / RVD130 to ensure
control, a fault status message will be delivered. The controller displays this as Er (er-
ror).
Optional sensors (shown with broken lines) cannot be monitored for open-circuits.
4.2 Flow temperature (B1)
4.2.1 Types of sensors
Suitable are all types of Siemens temperature sensors that use a sensing element LG-
Ni 1000 Ω at 0 °C:
• Strap-on temperature sensor QAD22
• Immersion temperature sensor QAE22...
4.2.2 Handling faults
If there is a fault in the sensor’s measuring circuit (short-circuit or open-circuit), the
controller will respond as follows (with all plant types):
• The heating circuit pump will be activated
• The 2-port valve in the primary return will be shut
If plant types no. 4...6 use no space heating, no fault status message will be generated.
In all other cases, a fault status message will be delivered:
• The controller’s LCD displays Er
• When interrogating the flow temperature on the QAW70 room unit – if present – its
display will show --- 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 (sensing element LG-Ni 1000 Ω at 0 °C), for connection to
terminal B9
• Outside sensor QAC32 (sensing element NTC 575 Ω at 20 °C), for connection to
terminal B9
The controller automatically identifies the type of sensor connected.
The range of use is –50...+50 °C.
4.3.2 Handling faults
If there is a short-circuit or open-circuit in the outside sensor’s measuring circuit, the
controller will respond as follows:
• Plants with room temperature sensor:
The controller switches to pure room temperature control.