ARCA Regler GmbH
13 Commissioning
Series 824
37 / 46
09.2018 / 1.0
13.2
Limit value transmitter
The limit contacts are normally adjusted so that a signal is present in
each of the end positions (open/closed). Both vanes can be infinitely ro-
tated so that intermediate positions can also be signalled. To ensure reli-
able switching, the switching point should be set approx. 2% before the
mechanical stop (open/closed). We recommend the valve position
"closed" for the limit value transmitter "A" and the valve position "open"
for the limit value transmitter "B", whose setting is described below for a
normally closed valve.
▪ Loosen the screws (81).
▪ Position the limit value transmitter (85) in the centre of the slots.
▪ Tighten the screws (81).
▪ Loosen the screw (82).
▪ Coarse adjustment of the two vanes (86) with input signal at 0% and
100%.
▪ Tighten the screws (82).
▪ Apply a 2% input signal.
▪ Loosen the screw (81) on the limit value transmitter "A".
▪ Adjust vane "A" so that a signal is present at the limit value transmit-
ter "A".
▪ Tighten the screws (81).
▪ Apply a 98% input signal.
▪ Loosen the screw (81) on the limit value transmitter "B".
▪ Adjust the vane so that a signal is present at the limit value transmit-
ter "B".
▪ Tighten the screws (81).
13.3
Position feedback
13.3.1
Feedback potentiometer
The rotary movement of the positioner shaft is transmitted to the poten-
tiometer (91) via a gear unit. The zero point and range setting must be
done on the downstream devices (not included in the scope of delivery).
13.3.2
Position transducer
The built-in position transducer (R/I) measures the change in resistance
of the feedback potentiometer and converts the input signal into the out-
put signal (0/4 - 20 mA). The zero point and range setting is done using
the screws provided for this purpose on the position transducer (92).