Watson & Sons 520DUN user manual Speed analogue output, Tachometer frequency output

22.5 Speed: analogue output

An analogue voltage output signal is available on the Tacho output connector (J11), between the V terminal and the 0V terminal. The voltage is fixed and directly proportional to the pumphead rotation speed. 0V = zero speed; 10V = maximum allowed speed.

A current analogue signal within the range 4-20mA is available between the mA terminal and the 0V terminal. The current is fixed and directly propor- tional to the pumphead rotation speed. 4mA = zero speed; 20mA = maximum speed.

Note: If the mA output is to be used for reading from a multimeter, a 250Ω resistor is required in series.

22.6 Tachometer frequency output

A tachometer frequency output is available on the Tacho output connector (J11), between the freq terminal and the 0V terminal. It provides a +5V square wave pulse, maximum 0.5mA, the frequency of which is directly proportional to pumphead rotation speed. It provides 5.717 Hz/rpm - 343 pulses per output shaft revolution. The pulse train from the pump can be used to calculate the speed of rotation or to determine the number of pumphead revolutions. This output has the required strength to be effective up to 3m from the pump. Longer cable runs require signal amplification.

Watson-Marlow 520DuN IP66/NEMA 4X User Manual 66