These data loggers offer absolute data security and integrity, combined with very easy and simple handling and operation. Collected data are safely stored in EEPROM and can be read either on-site using the special model 580 data collector or after transfer into the interface by the ComSoft3 software package. The different models offer either single parameter logging of environmental temperature, voltage and current or as the multi-channel loggers monitoring of several independent temperatures or temperature and rel humidity at the same time. Temperature and humidity sensors of all models are built in, and models 175-T2, 175-T3, 177-T3 and 177-T4 and 177-H1 also allow connection of external temperature sensors. Extenal humidity sensors cannot be used! The loggers are programmed via the interface and can be started after transport to their logging site by simply pushing one buttom. Once started, the loggers will record data for the preprogrammed time window using the specified interval timing. Max. and Min. limits can be set, and exceeding any limit value will be shown in the display, which otherwise will always show the last recorded values. The high speed interface transfers the logged data within less than 90 sec into any PC. Models 175 and 177 can be read even on-site without interrupting the programmed measurement cycles.