4195KA, KB, and KC Series
3–7
Figure
3–4. 4195KA Series Controller Schematic
SET POINT INDICATOR RESET BELLOWS (VENTED)
REVERSE ACTION
QUADRANT
PROPORTIONAL
BELLOWS
PROPORTIONAL
BAND ADJUSTMENT
FLAPPER PIVOT
DIRECT ACTION
QUADRANT
FLAPPER
NOZZLE
BEAM
CONNECTING
LINK
PROCESS POINTER
REMOTE SET POINT
CONNECTED HERE
INPUT ELEMENT
CONNECTED HERE
SUPPLY
PRESSURE
RELAY
OUTPUT PRESSURE
TO FINAL CONTROL
ELEMENT
SUPPLY PRESSURE
OUTPUT PRESSURE
PROPORTIONAL PRESSURE
NOZZLE PRESSURE
FEEDBACK
LINK
FEEDBACK
MOTION
INPUT
MOTION
46A9764-A
B1489-2 / IL
Remote Set Point (suffix letter M)
Operation
The capability to adjust the controller set point from a
remote location is available with all 4195KA Series
controllers. This option is designated by the letter M in
the type number.
A control pressure is applied to the capsular element
within the remote set point assembly. The expansion
and contraction of the capsule moves the set point
adjustment via a connecting linkage. Increasing the
control pressure to the capsule increases the set point
setting and decreasing the control pressure reduces
the set point setting.
Auto/Manual Station (suffix letter E)
Operation
A controller with the auto/manual station (designated
by the suffix letter E in the type number) has piping on
the output side of the relay as shown in figure 3–5.
Supply pressure to the relay is also applied to the
manual loader. The manual loader, functioning as a
regulator, applies pressure to one side of the plastic
tube and to the auto/manual switch. Output pressure
from the relay registers on the other side of the plastic
tube as well as in the auto/manual switch.
When the auto/manual switch is in the MANUAL posi-
tion, the manual loader output is channeled through
the auto/manual switch and becomes the controller
output. When the auto/manual switch is in the AUTO
position, the relay output is channeled through the
switch to become the controller output.
Before the auto/manual switch is operated, the relay
output must equal the manual loader output to avoid
bumping the process. Adjusting the set point varies
the pressure on the left-hand side of the plastic tube.
Adjusting the manual loader knob varies the pressure
on the right-hand side. When the pressures are equal,
the metal ball is centered in the tube and it is held in
place by a small magnet. A pressure imbalance forces
the ball to one end of the tube where it forms a seal,
blocking air flow through the tube.
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