Starting at $325.00
  • Usually ships in 1-2 weeks



  • HL20 logs humidity and temperature data
  • Both models available with or without a display
  • Highest accuracy at 0.8% RH and 0.2°C
  • Outstanding long term stability
  • 20000 data point memory with date & time stamps
  • Programmable alarm limits
  • Programmable recording intervals
  • Psychrometric calculations of dew and frost point values available
  • FDA 21 CFR Part 11/Gamp 4 compliant
  • UART to USB interface
  • Long battery life


The Rotronic HygroLog HL20 is the latest development of data loggers for relative humidity, temperature, dew point and frost point. This logger provides the accuracy and reliability to measure and record essential data whether it be in pharmaceutical clean rooms, storage facilities, manufacturing areas, buildings, museums or any other critical area. The HL20 is fully compliant with FDA 21 CFR part 11 and GAMP 4 requirements for electronic records and electronic signatures (ERES).

The foundation of the Rotronic HygroLog HL20 data logger is the AirChip3000 digital technology. The AirChip3000 temperature compensates humidity readings with over 30,000 reference points. It also enables dew/frost point calculation, sensor auto-diagnostics, automatic correction, and active alarming. The AirChip3000 also conforms to FDA21 CFR Part 11 and GAMP4 (audit trail).

The Rotronic HygroLog HL20 series data logger is available with or without a display. The display is backlit and has a battery charge indicator. It shows measured and calculated data with resolution to 2 decimal places and has a function key to start and stop logging.

The HygroLog HL20 logs up to 20,000 relative humidity and temperature value pairs. Each record is time and date stamped, the log interval is adjustable and there are two data recording modes: start-stop or loop. The HL20 has visible alarms that can be programmed to detect the following: an out-of-limits value, communication loss with the probe or a sensor failure and sensor drift.

The Rotronic HygroLog HL20 series data logger is also available as a set and includes the HL20, HW4 software and an AC3006 cable.


Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.


Please consider these optional accessories.