Watson-Marlow 520DuN IP66/NEMA 4X User Manual
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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 250
Ω
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.
