Watson-Marlow 620U - Manual (Page 61)

Watson-Marlow 620UN, 620U, 620SN, 620S User Manual 61
20.4 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 direct-
ly proportional to the pumphead rotation speed.
0V = zero speed; 10V = maximum allowed speed.
There is no mA output on this terminal for the
620UN. This is available on the 620DuN.
20.5 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 5.578 Hz/rpm - 334 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.
Important: general instructions for remote control inputs
All remote control inputs can be wired in two ways:
Logic
A logic voltage between 5V TTL and 24V industrial logic may be wired
to the input. The pump is configured to operate without modification
anywhere in this range. Any of the 0V terminals - though preferably
the 0V terminal associated with the desired input - is connected to the
control device’s 0V to make the circuit. Low is equivalent to 0V. High
is equivalent to 5V
→24V.
Switch
A remote switch may be connected between the input and any posi-
tive voltage supply from the pump - though preferably the associated
supply terminal. Do not use the 10V supply from the Rem-pot connec-
tor, however.