1-4
IM 05P01C31-01EN
1.3 Control Functions
Control Mode
The UT55A/UT52A are controllers equipped with 8 control modes. Some control modes
require a remote input (RSP) terminal.
For the auxiliary functions of control modes, see the respective sections.
Controlmodeschematicdiagram Description
Single-loop
control
PV
OUT
PID
“Single-loop control” provides the basic control
function having one control computation unit.
► 8.1.1Single-loopControl,Single-loop
Heating/cooling Control, Single-loop
Position Proportional Control, and Single-
loop Two-position Two-level Control
Cascade
primary-loop
control
PVSwitch
to AUTO
FAIL
TRK
SP output
PV
Cascade
RSP
OUT
DI
OUT
PID
RSP
RET DO
Primary
Secondary
PID
“Cascade primary-loop control” sets up a
controller as the primary-loop controller when
two controllers are used for Cascade control. It
is used in connection with “Cascade secondary-
loop control.” It provides the output tracking
function and FAIL output to the secondary-loop
controller.
Remote input (RSP) terminal is required for
output tracking input
► 8.1.2CascadePrimary-loopControl
Cascade
secondary-loop
control
PV
Switch
to AUTO
FAIL
TRK
SP output
PV
Cascade
OUT
PID
Primary
Secondary
PID
RSP
RET DO
RSP DI
OUT
“Cascade secondary-loop control” sets up a
controller as the secondary-loop controller when
two controllers are used for Cascade control. It
is used in connection with “Cascade primary-
loop control.” It provides the target setpoint
output function and tracking signal output
function to the primary-loop controller.
Remote input (RSP) terminal is required for
cascade input.
► 8.1.3CascadeSecondary-loopControl,
Cascade Secondary-loop Heating/cooling
Control, and Cascade Secondary-loop
Position Proportional Control