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Home » Devices » CO2 concentration » CO2 and O2 Meter LB-856

Carbon Dioxide & Oxygen Concentration Meter with Recorder - LB-856

LB-856 CO2 and O2 concentration meter
  • CO2 (carbon dioxide) concentration measurement
    • standard built-in
  • Additional measurement inputs:
    • O2 (oxygen) concentration meter (external sensor)
    • -60…+150°C thermometer (external temperature sensor)
    • analogue (any 0…10 V sensor)
    • any S300 sensor
  • Recording memory
    • capacity: 256 kB
    • CO2, O2, temperature, etc. recorder
  • Ethernet interface
    • 10/100 Mb/s
    • optional POE power supply
  • Standard communication protocols and data formats:
    • IPv4, IPv6
    • HTTP: HTML (WWW overview), JSON, XML
    • SNMP
  • Alarm signalling:
    • 16 independent alarms
    • SNMP TRAP sending
    • email sending (SMTP)
    • syslog messages sending
  • software
User manual

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Ethernet network configuration manual

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Online demo

A working device may be viewed at the following address:

General Description

The LB-856 CO2 concentration meter is used for collecting data from environmental measurements, subsequently shared via Ethernet interface via a range of communication protocols.

CO2 and O2 monitoring — Ethernet

Sample applications

Monitoring of rooms: CO2 and O2 concentration measurement, air humidity and temperature measurement (additional LB-710 sensor), recorder.

Mini weather station: CO2 and O2 concentration measurement and recording, air humidity and temperature, and atmospheric pressure measurement (additional LB-715 sensor).

Measurement inputs

The meter is equipped with an internal module for O2 concentration measurement and 4 measurement inputs for externally connected sensors:

CO2 (carbon dioxide) concentration

The basic version of the module provides a Co2 concentration meter without the need to connect external sensors.

O2 (oxygen) concentration

The O2 (oxygen) sensor input allows an external sensor to be connected — e.g. LB-856-O2 type, providing measurement in the range of 0–100%.


The thermometer input enables temperature measurement with the use of an external thermistor probe in the range of -60…+150°C. The dedicated probe with special thermistor provides for optimum precision of measurement amounting to 0.1°C in the range of -30…+100°C, and 0.5°C in the remaining range.

The thermistor probe is an optimum and money-saving solution for measuring temperature in most cases. If a temperature measurement is required in a wider range, with a higher precision, and in a considerable distance from the LB-856 module, or perhaps with a type/calibration certificate issued by the Central Office of Measures, than the temperature sensor with S300 interface may be used.


The S300 input of this CO2 recorder enables virtually any sensor to be connected with the S300 interface. The S300 is a digital current loop interface, providing double-wire connection of the sensor and allowing considerable distance between the sensor and the data collection module, at the same time powering the sensor via the module and delivering digital data from the sensor to the module.

In particular, the CO2 concentration meter is compatible with:

  • LB-710 — thermo hygrometer
    or any other device transmitting data in the format compatible with the LB-710;
    • LB-474C — temperature and humidity regulator;
    • LB-522 — thermo hygrometer;
    • LB-705 — panel thermo hygrometer;
    • LB-720/722 — dehumidifier controller;
    • LB-720C/722C — climate regulator;
    • LB-725 — panel thermo hygrometer;
  • LB-710T — thermometer;
  • LB-710E — thermometer with extended range;
  • LB-711 — 8-channel thermometer;
  • LB-715 — thermometer–hygrometer–barometer;
  • LB-716 — barometer;
  • LB-716P — absolute manometer;
  • LB-716D — differential manometer;
  • LB-746 — wind speed and direction meter;
  • LB-747 — wind speed and direction meter;
  • LB-750 — laboratory barometer;
  • LB-781 — the road sensor,
  • LB-797 — hygrometer for solid materials;
  • LB-850 — CO2 concentration and temperature meter;
  • LB-900 — solar radiation meter;
  • LB-901 — 2-channel solar radiation meter;
  • LB-905 — oxygen and other gas concentration meter;
  • LB-910 — surface humidity meter / flooding sensor;
  • LB-920 — soil moisture meter;
  • LB-921 — universal A/C converter.


Analogue input of the CO2 concentration meter enables voltage measurement, thus enabling the connection of any sensor with 0–10 V output.

CO2 and O2 recorder

The CO2 concentration meter is equipped with a built-in recording memory, allowing for automatic recording of CO2, O2, temperature and other values.

Ethernet interface

The Ethernet interface enables the incorporation of the LB-856 module in the data transmission network or direct connection to a PC. The interface may operate in 10/100 Mb/s modes.

An optional power supply over Ethernet — POE — is also possible.


The LB-856 module supports standard communication protocols, thus allowing simple integration with any measurement systems and existing software.


The IPv6 protocol support in the LB-856 meter enables it to be used in networks in which this protocol is employed, or in networks that will shortly require such a protocol. In the case of migration of current IPv4 networks to IPv6 protocol, the LB-856 module will not require any extra work or additional investments.

The mechanism of no-state auto-configuration of the IPv6 (SAC) address allows the incorporation of the LB-856 module in the network, without the need for individual configuration of each module.


The LB-856 module enables direct data overview in a web browser. The data are automatically updated every 10 seconds.


The LB-856 CO2 concentration meter shares data in JSON format, with the use of the HTTP protocol. Typical applications of the CO2 recorder are all network programs that are able to read out data in the below format.

The sample simple PHP script shows how the data from the CO2 meter may be read-out and incorporated in the WWW webpage: lb856-json.php


The LB-856 module shares data in XML format, with the use of the HTTP protocol. Typical applications are all network programs that are able to read out data in the following format.


The CO2 concentration meter shares all data in the form of SNMP protocol variables for the network management software (NMS).

SNMP monitoring enables obtaining information about the state of the network interface and read-out all measurement results obtained by the module. In a typical case such as server-room monitoring, the temperature may be monitored in a few places at ones, water flooding may be detected, and information may be received about door opening.

It is possible to programme threshold alarms for all measured values, which — when detected — trigger a trap (SNMP TRAP) sent to the NMS software. When an alarm state is detected, the NMS informs particular individuals via the use of the specified mechanisms (email, text message, etc).

SNMP monitoringSNMP monitoring


The LB-856 module shares all data in the form of MODBUS variables for SCADA class software. The standard MODBUS/TCP protocol is supported, according to the Modbus Organization Specification.


The CO2 concentration meter enables 16 independent alarms to be defined for the measured data. Alarms are signalled in the form of SNMP traps sent to a designated NMS address, email messages and syslog messages.

For every alarm the following may be configured:

  • correlation with the measured value (any measurement result from any given input), for which an alarm is to signalled;
  • a lower and upper threshold (an alarm signal is triggered when the lower or upper threshold is breached);
  • minimum breach time (filters out momentary changes that should not be signalled in a given application).).

The possibility of correlating every alarm with any of the measured data enables, for example, setting individual alarms for 16 different parameters, or, in extreme cases, 16 independent alarm ranges for one measured value.

Dedicated software

The device may additionally come with software for Windows — LBX software — enabling:

  • presentation of current readings from devices;
  • operation of devices — access to settings and all functions;
  • alarm monitoring and signalling;
  • presentation of archived data — charts, reports, histograms;
  • data archive management;
  • access for remote clients.
CO2 and O2 monitoring

Power supply

The LB-856 module is by default powered by an external 12 V power unit. This power source enables easy usage of the rechargeable battery power supply in systems that require it.


Optionally, the LB-856 CO2 recorder may be equipped with the POE module, providing a power supply via the Ethernet cable, without the need to use an external network power unit. This option features a simplified installation, eliminating the need to establish a connection with the electricity mains — e.g. in places, where it is not available or not convenient. The use of POE requires a suitable network infrastructure — the used network switches must be POE type ports; it is also possible to use an intermediary power unit (midspan).

Technical Data

CO2 concentration meter: LB-856
CO2 measurement Sensor: built-in, NDIR
Measurement range: 0…5,000 ppm (0…0.5%)
CO2 measurement precision: ±100 ppm / ±5% of the measurement value
Reaction time: 20 seconds
Warming-up time after switching the power on: ≤ 1 minute
Additional measurement inputs O2 sensor: external LB-865-O2
Measurement range: 0.0…100.0%
Measurement resolution: 0.1% or 0.01%
Measurement uncertainty: 0.1%
Temperature Sensor: external, 10k thermistor
Measurement range: -60…+150°C
Measurement uncertainty:
-0.1°C in the range of -30…+100°C
-0.5°C in the range of -60…-30 and +100…+150°C
Measurement resolution: 0.1°C
S300 Compatibility: any data source in the standard of S300 digital current loop
Data transmission: 300 bps 7/N/1
0…10 V Measurement range: 0.00…+10.00 V
Measurement resolution: 0.01 V
Measurement uncertainty: 0.01 V
RS-232 Universal input/output of the serial interface
Interfaces Ethernet 10/100 Mb/s, full-duplex / half-duplex, flow-control
POE (optionally on request)
Power supply External power unit Power supply voltage: 12…24 V DC
Power input: max. 2.5 W (without S300 inputs)
Each S300 input increases the power input by 25 mA (at 12 V power supply: 0.3 W)
POE (Power Over Ethernet)
(optionally on request)
36…57 V
Class 1 (max. 3.84 W)
Power supply via 1-2/3-6 data lines or via unused 4-5/7-8
Operation conditions Temperature range: 0…+50°C
Humidity range: 0…95%,
without water condensation
External dimensions Plastic housing 85 x 85 x 40 mm