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Laboratory Electronics


  • measurement characteristics for many materials
  • output interface RS-232
  • battery powered
Wilgotnociomierz LB-790 + LB-756


Meter LB-790 along with a reading panel LB-756 is used for relative humidity measurement of loose construction materials. The set is can be used as a stationary as well as a portable device. Panel LB-756 can be powered from a battery or from an outside power supply. The measurement result and the actual time and date are shown on a 32- character LCD screen. The sixteen key button membrane keyboard with which the panel is equipped and the multilevel menu shown on the LCD screen, make the device easy to use.

The relative humidity value of the tested material is set by the frequency measurement of the high frequency measurement generator. The generator's frequency is proportional to the condenser's value capacity that is also a meter’s sensor. The sensor's capacity depends on the dialectic's penetration value, which is used to test the material sample.

Before taking measurements of a tested material sample one should perform device calibration using two material samples for which the relative humidity values are already known. The calibration data is stored in the non volatile memory located in a measurement probe, so even if there is a short lack in power supply the calibration data is unaffected by it and stays stored. Panel LB-756 can cooperate with various probes type LB-790. In the non-volatile probe memory up to 24 calibration sets of different tested materials can be stored. At any time a user can choose an adequate set of calibration data, adequate for the type of the material tested. The user can also perform another calibration of the set chosen. In order to increase measurement accuracy few calibration sets can be used for one type of material. One set can cover wide humidity scope and be used to assess the humidity value of the tested material; the other sets can cover calibration data prepared for narrow humidity sub-ranges.

The main part of a program realizing humidity measurement algorithm is placed in the programmable constant panel LB-756 memory. Because of it a user has an option of getting program upgrades provided by a producer. The reprogramming is done after attaching the panel to a computer (additional connection cable) and starting a special loading program.


Scope of voltage
5,5...12 V DC
Energy consumption
15mA average
50mA maximum