Remote Set Point (Suffix Letter M) Operation; Auto/Manual Station (Suffix Letter E) Operation - Emerson Fisher 4195KA Instruction Manual

4195K Controllers
July 2018

Remote Set Point (suffix letter M) Operation

The capability to adjust the controller set point from a remote location is available with all 4195KA 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.
Figure 3‐5. Fisher 4195KA Auto/Manual Station Schematic
AUTOMATIC
POSITION
OUTPUT PRESSURE
TO FINAL CONTROL
ELEMENT
RELAY OUTPUT PRESSURE
SUPPLY PRESSURE
MANUAL LOADER OUTPUT PRESSURE
48A5230‐A
A2999‐1
When the auto/manual switch is in the MANUAL position, 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.
24
AUTO/MANUAL
SWITCH
RELAY
SUPPLY PRESSURE
Instruction Manual
MANUAL LOADER
MANUAL
LOADER KNOB
PLASTIC
TUBE
METAL
BALL
AUTO/MANUAL
SWITCH
OUTPUT PRESSURE
TO FINAL CONTROL
ELEMENT
D200160X012
MANUAL POSITION