Data loggers automatically record precise measurements in real time even when personnel cannot be present. The portable designs feature internally or externally located sensors that have exceptional sensitivity to record and store data in any application or environment needed. These electronic instruments have programmable tracking in single or multi-channel options. Enabling reading over long periods, the data loggers alert if conditions are abnormal for safety and optimum testing quality through visual or auditory alarms. These battery powered loggers have data acquisition system to measure and acquire data sample rates.