Instruments are intended for the measurement and the writing into the memory of value and waveform based on the external sensors. Sensors can be the most diverse: temperature, stress, humidity, pulses, rotation. With the aid of these registrars it is possible to conduct monitoring and control to 32 signals simultaneously, which come from different external sensors. Model 8420-51: 8 channels model 8421-51: 16 channels model 8422-51: 32 channels