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Laboratory Electronics

THERMOMETER – HYGROMETER LB-701 with a reading panel LB-702 BAROMETER LB-702B

  • functions: thermometer, hygrometer (humidity meter), recorder, barometer (optionally)  
  • measurement: temperature, air relative humidity, dew point temperature, water steam content
  • optional measurement: barometric pressure (with a panel version LB-702B)
  • portable device 
  • battery or network powered  
  • registry up to 640 measurement points
  • interface RS232C
Termometr higrometr LB-701 + LB-702


Attention: Panel LB-702/ LB-702B is not produced at this time- it was replaced by a new version- panel
LB-706/LB-706B/ LB-706T.

Thermometer - hygrometer LB-701 with a reading panel LB-702 is designed for air temperature and humidity measurement. The panel can be made in a version with an internal pressure sensor (version LB-702B). It is then possible to measure atmospheric pressure additionally. It is a portable device, powered from a battery or from an outside feeder cable calculator.

The device is composed of two major parts: a hytherograph LB-701 (made in a form of  a measurement probe) and a reading panel LB-702. Both parts are connected by 1...20 m cable.

The measurement probe LB-701 includes: a thin layer temperature sensor Pt-1000, thin layer capacitive relative humidity sensor, electronic processing systems and a system of programmed non volatile memory, where all individual probe characteristic are stored as well as identification and technical data. A replaceable casing, which type depends on what the device is used for, protects the measurement probe sensors. The device in a standard version is equipped with a sensor casing (anti pollution filter) type F1.

The reading panel receives signals that had been already processed that include coded information concerning temperature and relative humidity values. It allows on changeable use of different reading panels with the same hytherograph LB-701 without any influence on the measurement results.

The microprocessor from the device's reading panel, basing on information from the probe (processed measurement signals and read calibration characteristics) computes the values such as: relative humidity, temperature, dew point temperature and volume water vapor content in the air. In the panel version LB-702B there is and additional pressure sensor and a precise analog to digital converter inside of the panel. All of the results (temperature, humidity and optionally pressure) are presented on an alphanumeric LCD screen at the same time (2 lines for 16 characters) and can be sent out using an interface. The lack of switches increases device's reliability at work and simplifies its use.

The device is equipped with an interface RS232C, which allows for it to be attached to any computer system. It allows on remote control, automatic measurement data collection and entering the calibration data during the original and secondary calibration.

The panel LB-702 has a programmed local time clock, which counts the time from the moment of turning on the power supply, or synchronizes with the real time equipment clock, if such a device is installed in the device. The panel in a version LB-702PR also has additional equipment - a non-volatile memory of measurement results and a real time clock. It allows on using the device as a temperature, humidity and optionally air pressure register. The memory allows on storing approximately 400 measurement points.

The device does not have any mechanic calibration elements (i.e. potentiometers). The device's calibration means sending trough a digital interface to a device's non-volatile memory the calibration data obtained in model climate conditions. It guarantees comfort and high calibration accuracy as well as stability of the device's meteorological parameters in time.

Thermometer - hygrometer LB-701 has obtained a certificate of type RP T 95 76 issued by the President of the Central Measurement Office in Warsaw.

Thermometer - hygrometer LB-701 also has a positive expertise from The Central Army Meteorology Office in Zielonka (no. 71 dated 05.05.1995), performed basing on the method of legalizing hygrometers and hygrographs.

Thermometer - hygrometer upon a special order, can have an individual authenticating certificate from  the Central Measurement Office in Warsaw or (upon a request) from the Central Army Meteorology Office in Zielonka (for devices used in the Army). Barometer (upon an additional request) can have a calibration certificate from the Technical Institute of Air Force in Warsaw.

Methods used for relative humidity and air temperature measurement using a hytherograph are introduced in an additional description.


Measurement inaccuracy
+/- 0,2°C
Scope of measurement LB-701 -40..+85°C
Measurement inaccuracy +/- 2.0% in the scope 10...90%
+/- 4.0% outside of the scope 10...90%
Scope of measurement LB-701 10..95% for temperatures up to +40°C
10..60% for temperatures up to +70°C
10..40% for temperatures up to +80°C
Scope of measurement LB-701H 0..100% for temperatures up to +60°C
0..70% for temperatures up to +70°C
0..40% for temperatures up to +80°C
Measurement inaccuracy +/- 1.0 hPa in the scope of temperatures 0..+50 °C
Scope of measurement 700...1100 hPa
Scope of readings Resolution
Air temperature -40.0..+80.0°C 0,1°C
Relative humidity 0.0..100.0% 0,1%
Dew point temperature -40.0..+100,0°C 0,1°C
Volume water vapor content in the air 0..99999ppm 1ppm
Time months, days, hrs., min 1 min
Pressure (optionally) 700...1100 hPa 0.1 hPa
4 batteries R6 (AA)
Network stabilized feeder 9V DC
interface RS232C not active app. 15 mA
interface RS232C active app. 25 mA
Probe LB-701 -40..+85°C  
Panel LB-702 0..+50°C  
Scope of temperatures 10..40°C
Scope of humidity 20..80%
Level of environment corrosion aggressiveness accord. PN-71/H-04651


Series RS232C, 4 lines (RxD, TxD, DTR, GND), switching on the interface's power supply system active line stage DTR from a computer, transmission parameters: 9600 bps, 8 bits of information, without evenness control, 1 stop bit.
Possibility of reading the measurement results and storing of device's calibration in its non volatile memory.


Approximately 185x100x45 mm - the case for the reading panel with a screen (calculator type) and connected with a cable 1...20 m in length the measurement probe dimensions diameter 25 mm, length 130 mm (for a metal case probe: diameter 18 mm, length 150 mm).


  • power pack and a cable for the interface RS232C,
  • stand for a probe LB-701,
  • program "User's Interface" for a PC computer,
  • 4 batteries R6.

EQUIPMENT optional 

  • protective cover hand bag


The following versions are available upon a special order:
  • LB-701H- with extended compared to standard, range of constant humidity measurement to 0...100%,
  • LB-701Fn-  sensor casing version (according to a description), the version is given if it is different than F1,
  • LB-702PR- with a reading panel equipped with the RTC clock and additional memory for the measurement results (storage capacity 80 or 640 measurement points),
  • LB-702B- with a reading panel equipped in an air pressure sensor.
Other panels that collaborate with the probe LB-701: LB-705, LB-706, LB-706B, LB-725.