Changing Controller Action; Switching The Auto/Manual Station; Prestartup Checks For 4194Ha Controllers - Emerson Fisher 4194HA Instruction Manual

Instruction Manual
D200156X012
(0 to 15 psig). Then, at a proportional band setting of 100 percent DIRECT, the controller output goes from 3 to 15
psig as the process pressure differential goes from 0 to 15 psig. If the proportional band setting is subsequently
changed to 50 percent DIRECT, the controller output would change from 3 to 15 psig as the process pressure
differential changed from 0 to 7.5 psig.
Adjusting the proportional band has minimal effect on the set point.

Changing Controller Action

Controller action is switchable from direct to reverse or vice versa by simply loosening the screws on the proportional
band indicator cover and moving the cover out so the proportional band knob can be rotated to the desired action.
The white portion of the adjustment enables direct controller action. The black portion enables reverse controller
action.
Switching The Auto/Manual Station (suffix letter E)
Note
Switching the controller between automatic and manual mode without balancing can disturb the process and cause controller
cycling.
Refer to figure 6‐5 if the controller has the auto/manual option.
To switch from automatic to manual mode, you must balance the manual output with the controller output.
Two balance methods are available to equalize the manual output with the controller output.
To switch from automatic to manual mode, carefully adjust the loader knob until the metal ball inside the plastic tube
moves into the switching zone. Then move the automatic/manual switch to MANUAL. Turn the loader knob clockwise
to increase the controller output or counterclockwise to decrease it.
To switch from manual to automatic mode, adjust the set point manually or with remote set point pressure to move
the ball into the switching zone. Turn the switch to AUTOMATIC and adjust the set point manually or with remote set
point pressure to control the output.
When the automatic/manual switch is in AUTOMATIC, adjusting the loader knob has no effect on the controller
output. When the automatic/manual switch is in MANUAL, changing the set point adjustment has no effect on the
controller output.

Prestartup Checks for 4194HA Controllers

Refer to figure 3‐1 for location of adjustments and refer to figure 6‐1 for location of key numbers.
When performing the checks, open loop conditions must exist. An open loop exists when the controller output does
not affect the input pressure or other control signal to the controller.
Note
If the controller has the auto/manual option (suffix letter E), be sure the controller is in the automatic mode before performing the
prestartup checks.
4194HA, HB, HC Controllers
July 2018
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