1. The tubing must be reversed. C+ tube must now go to C- and C- must go to C+.
So for double acting actuators you do exactly that, just reverse the tubing, for single acting,
C+ would now be plugged and C- would now be piped to the actuator.
2. Remove the front cover and the indicator in order to expose the cam nut and cam-notice
the cam position.
3. Loosen the cam nut and take the cam out and flip it over-literally 180 degrees.
Place the cam back in the positioner making sure that it is on the opposite lobe side.
(example: on a C1 cam it would go from the C1 A 90D side to the C1 B 90R side)
DO NOT TIGHTEN THE CAM NUT
.
4.
a.
is for double acting applications,
b.
is for single acting applications
a. For double acting applications apply supply air to the positioner. This should move the valve
open, the desired 4mA position. Now simply tighten cam nut. Now the positioner will be
working 4mA Open to 20mA close.
b. Since the positioner was set up originally 4mA closed we must now apply air to the
actuator to get the valve
to move to open. This is
done by pushing up on the
balance arm. The
balance arm is labeled
#2
in this picture. As you can
see the balance arm is
connected to the spool
valve
(#6)
through
connection
#7
. By pushing
up on the balance arm we
are exhausting air out of the
C- port. Once the valve is
open continue to hold the
balance arm up and tighten
the cam nut. Once the cam
nut is tightened release the balance arm, the positioner is now set to operate from
4mA open to 20mA closed.
The positioner should now be operating as 4mA is open and 20mA is closed.
Note: This will not change the “fail safe” action on an actuator with springs (usually
single acting application). To change the fail safe action you should contact the actuator
manufacturer.
