HygroClip Technology

Probes based on the HygroClip^® technology include two main subsystems:

· ASIC (Application Specific Integrated Circuit): this custom designed circuit measures both the capacitive humidity sensor and the Pt100 RTD and converts the measurements into digital counts. The ASIC also includes two D/A converters that convert the data from the micro controller into analog output signals. The ASIC regulates all supply voltages and generates the reset and clock signals for the micro controller.

· Micro controller / EEPROM: the micro controller uses the counts generated by the ASIC to compute the value of humidity and temperature. Calibration data, linearization and other sensor data are memorized in the EEPROM. The micro controller sends data both to the DIO pin (digital output signal) and to the ASIC (analog output signal).

Higher Accuracy: within a small package, digital processing of the humidity and temperature signals results in several improvements over conventional measuring systems:

• accurate linearization of the sensors over the entire range of measurement

• temperature compensation of the humidity sensor over the full operating range

Digital Signal Transmission: while the HygroClip technology has provisions for converting the digital signal into conventional analog output signals, direct use of the digital input/output (DIO) offers:

• greater signal resolution: up to 0.004%RH and 0.004°C

• higher reliability of data transfer through the elimination of intermediate analog circuits

• potentiometer-free calibration without opening the probe

• added flexibility regarding humidity computations, data recording, unit conversions, etc.