YOKOGAWA UT55A User Manual

6-22
IM 05P01C31-01EN
In Cascade control, perform Loop-2 auto-tuning in AUTO and RUN modes, then Loop-1
auto-tuning in Cascade and RUN modes.
LampStatus
Status STOPlamp CASlamp MANlamp
During auto-tuning of Loop-2 Unlit Unlit Blinking
During auto-tuning of Loop-1 Unlit Lit Blinking
Description
Auto-tuning is a function with which the controller automatically measures the process
characteristics and sets PID constants, which are control-related parameters, to optimum
values for the setpoint. Auto-tuning temporarily executes ON/OFF control, calculates
appropriate PID constants from response data obtained, and sets these constants.
 CAUTION
Do not perform auto-tuning for the following processes.
Tune PID manually.
● Processeswith
fastresponsesuchasflowratecontrolandpressurecontrol.
● Processeswhichdonotallowtheoutputtobeturnedonandoffeven
temporarily.
● Processeswhichprohibitoutputchangesatcontrolvalves(orotheractuators).
● ProcessesinwhichproductqualitycanbeadverselyaffectedifPVvalues
fluctuate beyond their allowable ranges.
AT = Started
ON
OFF
Temperature
SP
Control
output
Time
ON/OFF control
PID control using PID
constants calculated from
the AT results
Auto-tuning in progress
MAN lamp blinkng
There is a hysteresis of 0.25% of the input range above and below SP.
WhenSPbiasinauto-tuningisset
AT = Started
ON
OFF
Temperature
SP+AT.BS
SP
Control
output
Time
ON/OFF control
SP bias in auto-tuning
(negative setpoint)
PID control using PID
constants calculated from
the AT results
Auto-tuning in progress
MAN lamp blinkng
There is a hysteresis of 0.25% of the input range above and below SP.
6.3PerformingandCancelingAuto-tuning

YOKOGAWA UT55A Specifications

General

Brand	YOKOGAWA
Model	UT55A
Category	Temperature Controller
Language	English