The basic function of the device LB-850 is measurement of carbon dioxide concentration CO2 content in the atmospheric air. The additional device functions are: temperature measurement, signaling exceeding the alarm conditions and regulation connected with CO2 and temperature measurement.
The device LB-850 is a stationary device, of small size, powered from an outside power supply. The meter is characterized by a modern construction based on the NDIR method (non-dispersive infrared method of not scattering an infrared stream). It is relays on measurement of attenuation of infrared radiation of a defined wave length put through the measured gas, which is suppressed depending on the carbon dioxide content in the examined gas. The NDIR method assures accurate and stable measurement result as well as failure-free work for many years. A sensor for CO2 measurement is placed inside of the device and the measured air can be supplied from the outside using the connection pipes, what allows on bringing the gas using a pipe to a remote place. The device can be made in a version with different measurement scopes depending on the application (standard: 10000 ppm).
An outside sensor attached to the device’s clamps is used for
temperature measurement. In the temperature sensor a precise
thermoresistor was applied, which assures measurement repeatability
even if the sensor is exchanged for a different one.
The device has few output interfaces, what allows on using it in
many applications. A digital interface RS-232 is used during the
meter’s calibration and is used for connecting the device to a digital
system of measurement result collection (specialized software lbx500),
just like an interface S300
LAB-EL. The device has also two analogue outputs: one 4..20 mA and one
0..10V that can be used for measurement results output or (optionally)
for proportional controlling of the executive devices (i.e. a valve, a
fan) in the process of CO2 concentration regulation. Two transmitter
outputs can be used for signaling exceeding the alarm conditions or for
regulation in a mode on/off (i.e. ventilation).
The actual measurement results of CO2 concentration and temperature are visible on an alphanumeric illuminated LCD display. A built-in keyboard is used for programming the alarm thresholds and (optionally) the parameters associated with regulation. Exceeding the programmed alarm thresholds is signaled by a built-in buzzer and the LED diodes placed on a front panel of the device.
The measurement results can be (optionally) registered in a built-in device memory (approximately 30000 measurements) and read later on through the interface RS-232.The device casing is adapted for assembly on a bus rail TS35. The device is powered from a network 230V/50Hz or optionally from a source 24V AC/DC.
The scope of meter usage can be in example:
|CO2 sensor type
|Scope of measurement of CO2 volume content
||0...10000 ppm (0...1%)
|CO2 measurement accuracy
||+/- 5% of the actual indication +/- 50 ppm
|Standard scope of the analogue outputs
|Meter heating time after power supply switch on
Outside, with a
|Maximum scope of measurement
|Measurement accuracy in the scope –15...+70°C||+/- 0,2°C +/- 1 last digit
|Measurement accuracy in the scope –35...+100°C
||+/-0,5°C +/- 1 last digit
|Measurement accuracy outside of the scope
||+/-2°C +/- 1 last digit
||Insulated, wattless, voltage 8..29V,
||Not insulated, minimum load 1000 ohm, scope
|Analogue 4...20 mA
||Insulated, wattless, outside power supply
scope 0...10000 ppm
||2 outputs, 1A/250V, resistance load, alarm or
|Scope of work temperatures
|Scope of air relative humidity
||230V/50Hz/3VA (optionally: power supply 24V
||115 x 90 x 62 mm