4150K and 4160K Series
11
Figure 8. Proportional-Plus-Reset Controller Adjustment Locations
RESET ADJUSTMENT KNOB
PROPORTIONAL BAND
ADJUSTMENT KNOB
PRESSURE SETTING KNOB
(KEY 36)
PRESSURE SETTING
DIAL (KEY 38)
ADJUSTER SCREWS (KEY 43)
CALIBRATION ADJUSTER (KEY 41)
FLAPPER (KEY 45)
NOZZLE (KEY 57)
48B6002-A
A5433-3 / IL
For example:
200
2 psig
30 psig
^
13%
(1.3 proportional band setting)
4. Proportional Action
Disturb the system by tapping the flapper lightly or
change the set point a small amount and check for
system cycling. If the system does not cycle then low-
er the proportional band (raising the gain) and disturb
the system again. Continue this procedure until the
system cycles. At that point, double the proportional
band setting.
Note
Proportional band adjustment affects
the set point. Proportional-only control-
lers will show some offset from set
point depending upon proportional
band setting and process demand. After
adjusting the proportional band, re-zero
by carefully rotating the nozzle (key 57)
until the steady-state process pressure
equals the process pressure knob read-
ing.
This tuning procedure may be too conservative for
some systems. The recommended proportional band
setting should be checked for stability by introducing a
disturbance and monitoring the process.
Proportional-Plus-Reset Controllers
This section describes the adjustments and proce-
dures for calibration and startup. The adjustment loca-
tions are shown in figure 8 unless otherwise specified.
All adjustments must be made with the cover open.
When the adjustments and calibration procedures are
complete, close and latch the cover. To better under-
stand the adjustments and overall operation of the
controller, refer to the Principle of Operation section in
this manual for proportional-plus-reset controllers. Re-
fer also to the schematic diagram in figure 14.
Adjustments
Adjustment: Set Point
Adjust the pressure-setting knob by turning the knob
clockwise to increase the set point and counterclock-
wise to decrease the set point.
Rotate the knob until the indicator points to the desired
set point pressure value. The pressure setting dial will
reflect the desired set point if the controller is accu-
rately calibrated.
Adjustment: Proportional Band
To adjust the proportional band, rotate the proportional
band knob to the desired value.
