This manual describes the functions and use of the HygroLog HL20 and HL21 data loggers.
The Rotronic HygroLog HL20 is a relative humidity and temperature logger capable of recording up to 20,000 pairs of values within ranges of -10 to 60°C and 0 to 100% RH. The HL21 model functions as a dedicated temperature data logger for the same range. Both models utilize internal sensors (Pt100 RTD for temperature and Hygromer IN1 capacitive sensor for humidity) and are powered by three AA batteries, offering up to 20 months of operation depending on settings.
| Relative humidity range (HL20) | -10 to 60°C and 0 to 100 %RH, non condensing |
|---|---|
| Temperature range (HL20/HL21) | -10 to 60°C (14 to 140°F) |
| Memory capacity (HL20) | 20,000 pairs |
| Memory capacity (HL21) | 20,000 values |
| Power source | Three AA batteries (1.5V) |
Battery lifetime depends on usage; models without an LC display can record data for up to 20 months, while those with a display and sleep function enabled last about 13 months.
No, the HL20 and HL21 do not have a power on/off switch because they must always keep track of the date and time.
No, while it can calculate and display the dew or frost point as a parameter, it cannot be used to record these values.