Flowserve NRR 2-40 - Manual (Page 20)

20
Commissioning
– continued –
Calibrating the feedback potentiometer of an external control valve
The feedback potentiometer of an external control valve with electric actuator has to
be manually calibrated before commissioning.
1. Ascertain the total resistance of the feedback potentiometer.
2. Set the control valve manually into mid-position.
3. Adjust manually the position of the feedback potentiometer until the partial
resistance values of the measured total resistance are equal.
■ The GESTRA level controller type NRR 2-40 requires a 1000
Ω Ω Ω Ω Ω
feedback potentiometer.
■ The NRR 2-40 works as two-position controller when the terminals for
the feedback potentiometer are not wired or the feedback potentiometer
is defective.
■ Use the control and display unit URB 1 for semi-automatic calibration of
the feedback potentiometer of an external control valve without
measurement of the resistance value. For more details see the
installation instructions of the URB 1.
Fig. 12
Attention