E-78-D is a microprocessor-controlled instrument that operates with the principle of frequency and period measurement. With impact sensors, it can be used to measure process variables such as speed, speed and timer.
 
Frequency of the input signal should be between 0.2 Hz and 10 kHz. Depending on the selected input type, it calculates the frequency differences and ratios of these inputs by measuring the frequencies and periods of the signals from two different inputs. Values are multiplied by the Pscl1 parameter and divided by the Pscl2 parameter and displayed on the screen.
 
The instrument checks the output relays by comparing the SET1 and SET2 values that can be set with the process value. With the RS-485 communication port, the instruments configuration parameters and results can be transmitted to other instruments via the Modbus protocol.