Baud rate
Transmission rate of serial interface.
Electronic output
After reaching the preset value, a positive (PNP) or negative (NPN) signal is emitted at the output
(transistor or optocoupler).
Emitted interference
Electromagnetic pulses emitted by devices that are spread over the air or over lines (EN 50081).
Interference immunity
The capacity of a device to continue to operate correctly and without functional restriction in sprite of electromagnetic interference (EN 50082).
LED-display
Self-luminous, easy-to-read
7-segment display.
LCD-display
Liquid-crystal display. Can be read thanks to background illumination or normal light incidence.
Protection
It is indicated according to DIN 40050 and IP (International Protection) followed by a 2-digit number. 
Relay output
A relay is switched when the preset value has been reached.
Interfaces
Used to communicate (input and output) with external systems.
Limit value
An output is switched when this value has been reached or exceeded (up or down).
Classifications
Classifications (EN 61010) are descriptions of connected protective measures against electric shock.
Scaling factor (electronic gear)
Multiplier to evaluate input pulses. Possibility of evaluating incoming pulses and thus of adapting electronic and mechanical equipment.
Reset
Return to initial value of tachometer.
Timeout
A reset of the display is effected in case the pulses were interrupted after this period has lapsed.
Parity
Control bit for error recognition of data received serially.
Totalizer
A counter that counts the input pulses by adding or subtracting them without any kind of control function.
Update time
Repeated display or measurment cycle.
VAC
Voltage supply: Alternating current.
VDC
Voltage supply: Direct current.