YOKOGAWA UT55A - Page 32

1-7
IM 05P01C31-01EN
Introduction to Functions
1
1.3 Control Functions
Two-positionTwo-levelControl
Two-position two-level control has two target setpoints to control ON and OFF
respectively.
► 8.2.4Two-positionTwo-levelControl
OFF
ON
Output
PV
Main SP
Initial value: Reverse
Hysteresis Hysteresis
Sub-SP
Initial value: Direct
(offset from main SP)
SamplePIControl
Sample PI control is useful for processes with long dead times where the results of the
controloutputarenotquicklyreflectedonthePV.
► 8.2.6SamplePIControl
BatchPIDControl
BatchPIDcontrolisusefulforcaseswherecontrolisperformedcausingthePVtosettle
to a SP as quickly as possible without overshooting.
► 8.2.7BatchPIDControl
Feedforward Control
Feedforward control cancels the disturbance before the effects of the disturbance appear
in the controlled system by applying a signal – to correct for the disturbance – directly to
the controller.
► 8.2.8FeedforwardControl