Data Sheet for Product

QPA20xx Series Indoor Air Quality Room Sensors Technical Instructions
Document Number CE1N1961
July 26, 2019
Siemens Industry, Inc. Page 3
CO
2
/VOC Concentration
(QPA2002 and
QPA2002D Only)
The sensor acquires and evaluates the CO
2
/VOC concentration and converts it to a
ventilation demand signal.
It represents the result of maximum selection of the CO
2
measuring signal and the
filtered VOC measuring signal. With maximum selection, the two demand signals are
compared and, depending on the result and the selected VOC sensitivity, delivered as
the common air quality demand.
The ventilation demand signal is delivered via output X2 as a signal to be fed to the
ventilation controller.
Figure 2. VOC Signal Output (X2).
VOC Sensitivity
Using jumper X130 on the setting element for the measuring range, the impact of VOC
ventilation demand on maximum selection against CO
2
ventilation demand can be
changed.
The position in the middle (R2) produces normal sensitivity of the VOC signal (factory
setting). The other two positions are used for increasing (R3) or decreasing (R1) VOC
sensitivity. See Figure 3.
Response Time VOC
Signal
Before the processor handles a change of the measured VOC value for maximum
selection, there is a delay in response time of three minutes for every Volt the signal
value changes.
Relative Humidity
(QPA2062 and
QPA2062D Only)
The sensor acquires the relative humidity in the room with a capacitive humidity
sensing element whose capacitance changes as a function of the relative humidity.
An electronic measuring circuit converts the signal from the sensing element to a
continuous signal, corresponding to a relative humidity range of 0 to 100%.
Temperature
(QPA206… Only)
The sensor acquires the room temperature with a sensing element whose electrical
resistance changes as a function of the temperature.
The change is converted to an output signal with a selectable measuring range ( 32°F
to 122°F [0°C to 50°C] or -31°F to 95°F [− 35°C to 35°C]).