THERMOMETER – HYGROMETER LB-701 with a reading panel LB-705

  • functions: thermometer, hygrometer (humidity meter), recorder
  • measurement: temperature, air relative humidity
  • optionally a probe LB-701T for temperature measurement in the extended scope
  • stationary device
  • big, easy to read screen 
  • internal measurement registry 
  • interface RS232C and a digital current loop
Thermometr - hygrometr LB-701 + LB-705


Thermometer - hygrometer LB-701 with a reading panel LB-705 is designed for air temperature and humidity measurement in locked places (warehouses, laboratories etc.). It is a stationary device, powered from 220V/50Hz network supply or from an outside source of 12V constant voltage.

The device is composed of two major parts: hytherograph LB-701 (made in a form of  a measurement probe) and a reading panel LB-705. A cable 1 meter in length connects both parts. There is a possibility of extending the probe’s cable up to 14 m. Replaceable casings protect the measurement probe sensors (their type depends on what the device is used for). The device in a standard version is equipped with s sensor casing (anti pollution filter) type F1.

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.

The reading panel receives signals that had been already processed, which 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 the information from the probe (processed measurement signals and read calibration characteristics) computes the following values: relative humidity, temperature, dew point temperature and volume water vapor content in the air. The temperature and relative humidity values are presented on the alphanumeric LCD screen at the same time (the size of numeric characters 25 mm) and can be sent out through the interface. The lack of switches increases device's reliability at work and makes its use a lot easier.

The device is equipped with two serial interfaces: RS232C, which allows for it to be attached to any computer system and with a LAB-EL digital current loop for data transmission to long distances. The interfaces allow on remote and automatic measurement data collection and entering the calibration data during the original and secondary calibration.

Panel LB-705 has a programmed local time clock, which counts the time from the moment of turning on the power supply, or synchronizes it with the time real equipment clock. The panel has a non-volatile memory of measurement results (capable of storing approximately 640 measurement points) what along with a real time clock allows on using it as a temperature and humidity recorder. An interval between the entries can be set from 1 up to 90 minutes (with a 1 minute stop) or from 100 to 1580 minutes (with a 10 minute stop). The device is quipped with a PC computer program used for setting the registry parameters and for reading the memory.

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

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

Thermometer- hygrometer LB-701 received 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.

Each thermometer-hygrometer, upon a special order, can have an individual calibration certificate from the  LAB-EL Calibration Laboratory.

LB-701T The device is produced also in a version for temperature measurement  (thermometer LB-701T with the panel LB-705). Thermometer LB-701T has a measurement converter (in a cylinder case) and an outside temperature sensor Pt1000 (or Pt100) in a standard or special case, adjusted to the individual user requirements (i.e. in a form of a rod from the acid resisting steel, with a special cable). Special version of the sensor casing allows on different values measurement in an extended scope of temperatures (-200...+550°C). Thermometer LB-701T can be also purchased separately, as additional equipment for the set LB-701/LB-705. However, in such case it is required that the internal software for the older versions of panel LB-705 is updated. Thermometer LB-701T cable length amounts to: between an outside temperature sensor and a converter - 1..40 m, between a converter and a reading panel - 1..15 m (the cables length is defined by the customer).

Methods used for relative humidity and air temperature measurements using hytherographs are introduced in a description below.


Measurement inaccuracy
+/- 0,1°C
+/- 1 last digit
Scope of measurement  -40.. +85°C
-200.. +550°C
LB-701T - sensor in a special casing
Measurement inaccuracy
+/- 2,0%
+/- 4,0%
in the scope of 10.. 90%,  +/- 1 last digit
outside of the scope 10.. 90%
Scope of measurement LB-701
10.. 95%
10.. 60%
10.. 40%
for temperatures up to +40°C
for temperatures up to +70°C
for temperatures up to +80°C
Scope of measurement LB-701H 0.. 100%
0.. 70%
0.. 40%
for temperatures up to +60°C
for temperatures up to +70°C
for temperatures up to +80°C
Scope of readings
Air temperature (LB-701)
-40,0.. +85,0°C 0,1°C
Air temperature (LB-701T)
-199,9.. +550°C
Relative humidity
0,0.. 100,0%
MEASUREMENT READINGS (additional using a series interface) 
Scope of readings
Dew point temperature
Volume water vapor content in the air
1 ppm
months, days, hrs., min
1 min
Probe LB-701M
-40,0.. +85,0°C

Thermometer sensor LB-701T
for a standard version 
for a special version 
Thermometer converter LB-701T
-40,0.. +85,0°C

Panel LB-705

Scope of temperatures
Scope of humidity 20..80%
Level of environment corrosion aggressiveness accord. PN-71/H-04651 
Degree of casing protection
IP 60 (limited additionally by the class of filter protection)
*) - Going beyond recommended constant work conditions (i.e. when installing the device in the open space) requires using additional protection means for the device's electronic part so that water out dropping does not start inside of the device (protecting the electronic part with silicone or using an additional external case).
Network 230V AC / 50Hz / 10VA
Low voltage feeder 12V DC / 0.4A


Series RS232C, 3 lines (RxD, TxD, GND), transmission parameters: 9600 bps, 8 bits of information, without the evenness control, 1 stop bit.
Creates a possibility of reading the measurement results and storing of the device's calibration in its non-volatile memory.


Series so called digital current loop, 1 line TXD (active TXD line stage complies with 25 mA current, in the rest stage 15 mA), time transmission parameters in accordance with RS232C: 300 bps, 7 bits of information, without evenness control, 1 stop bit.
Possibility of sending automatically the measurement results to long distances in big measurement systems (i.e. to multi sensor climate supervision systems - see LB-731). Galvanic isolation output.




The following effects are available upon special order:
Other panels that collaborate with the probe LB-701: LB-702, LB-704, LB-706, LB-706B, LB-725.
Elektronika Laboratoryjna Produced by: LAB-EL Laboratory Electronics
68b, Bodycha Str., 02-495 Warsaw
tel: (022) 667 71 18, 0601 209656, fax: (022) 867 53 32
e mail:
home page:
internet meteorological station:
meteorological station on a mobile phone:
Last updated: 25.03.2005
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