Siemens QMX3.P37 Technical Principles page 21

Fan control
(QMX3.P34, P74, P37)
Room operating modes
(QMX3.P34, P74, P37)
Presence button
(QMX3.P34, P74, P37)
Comfort extension
(QMX3.P34, P74, P37)
Air quality measurement
and assessment
(QMX3.P70, QMX3.P74)
Notes on CO sensor
2
Siemens
Building Technologies
controllers is available.
The setpoint (from local operation or received via bus) directly influences the first
threshold value (see description in sections 5.5.4 and 5.5.6).
Room temperature controller, humidity threshold value, and air quality threshold
switching can be activated or deactivated. As a result, simple sensor function or
room operation is possible also.
Manual room fan control can be enabled, offering three different types for selection
such as single stage, 3 stages, or continuous from 0 to 100 percent. The 9 display
bars change after 10% (display: 10% one bar, ...100% 9 bars). For manual
operation, a bar is added on each button press, corresponding to a change of +/-
11%. This function can be activated or deactivated.
Fan control is independent of the room temperature. When the fan operating mode
is Auto, the setpoint value via bus is executed.
The room operating modes can be controlled from Auto to Comfort, Pre-Comfort,
Economy, and Protection. This function can be activated or deactivated.
The presence button allows for manual changeover between Comfort and Pre-
Comfort. This function can be activated or deactivated. When activated, the
Comfort extension is not available (key 8, see section 4.3).
When the presence function is deactivated, Comfort can be extended.
Extensions are set between 5 and 120 minutes in ETS.
This function can be activated or deactivated (key 8, see section 4.3.
The following table provides information on assessing room air quality based on
the determined CO
concentration.
2
[ppm] Typical CO concentration
2
<400 Outside air
700 City air
1000 Comfort limit
1500 Ventilation strongly recommended
2000 Inacceptable indoor air quality
4000 Bedroom at poor ventilation
5000 Max. concentration for workspaces (MAC value)
40000 Exhaled air
CO concentration measurements are influenced by air pressure and temperature.
2
The lower the air pressure, the lower the measured value. Temperature influence is
corrected automatically. The sensor allows for correcting the determined measured
value to the prevailing average air pressure at the mounting location. To do this,
altitude [m above sea level] must be set. The correction has the following effect on
an uncorrected measured value of 1000 ppm at normal conditions (0 m altitude,
25 °C):
Altitude [m] 0
CO [ppm] 1000
2
• Function: The sensor determines the CO
measurement (NDIR). The sensor is maintenance free in normal environments,
thanks to the built-in self-correcting ABC (Automatic Baseline Correction)
algorithm. This algorithm keeps track of the sensor's lowest reading within 8
Wall-mounted sensors and room operator units for KNX/ETS and KNX/ACS
Functionality / Use
500 1000 1500 2000
1095 1201 1317 1445
concentration via infrared absorption
2
2500 3000
1586 1740
CM2N1602en_05
2018-09-14
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