TWO POSITION CONTROL SYSTEMS
Process Controls
Two Position Controller
A two position controller is a device that has two operating conditions: completely on or
completely off.
Figure 12 shows the input to output, characteristic waveform for a two position controller that
switches from its "OFF" state to its "ON" state when the measured variable increases above the
setpoint. Conversely, it switches from its "ON" state to its "OFF" state when the measured
variable decreases below the setpoint. This device provides an output determined by whether the
error signal is above or below the setpoint. The magnitude of the error signal is above or below
the setpoint. The magnitude of the error signal past that point is of no concern to the controller.
Figure 12 Two Position Controller Input/Output Relationship
IC-07
Page 18
Rev. 0
