Rt (Robust Tuning) - Omron E5CN-HT User Manual

Determining the PID Constants (AT or Manual Settings)
Operation Level
PV
C
25.0
0.0
Note
3-8-2

RT (Robust Tuning)

r t
RT Features
68
4. To return to the operation level, press the O Key.
PID Constants
When control characteristics are already known, PID constants can be set
directly to adjust control. PID constants are set in the Proportional Band (P),
Integral Time (I), and Derivative Time (D) parameters, according to the Dis-
play PID Selection parameter setting in the PID setting level. Changing the
Proportional Band (P), Integral Time (I), or Derivative Time (D) parameter set-
tings in the adjustment level changes the settings in these parameters in the
current PID set.
• When auto-tuning is executed with robust tuning selected, PID constants
are automatically set that make it hard for control performance to degen-
erate even when the characteristics of the controlled object change.
• RT can be set in the advanced function setting level when PID control has
been set.
• The RT mode cannot be selected while an analog input is set.
• Selecting the RT mode in the following cases will help to prevent hunting
from occurring.
• When the set temperature is not constant and is changed in a wide
range.
• When there are large variations in ambient temperatures due to factors
such as seasonal changes or differences between day and night tem-
peratures.
• When there are large variations in ambient wind conditions and air
flow.
• When heater characteristics change depending on the temperature.
• When an actuator with disproportional I/O, such as a phase-control-
type power regulator, is used.
• When a rapidly heating heater is used.
• When the control object or sensor has much loss time.
• When hunting occurs in normal mode for any reason.
• PID constants are initialized to the default settings by switching to RT
mode.
• When the RT mode is selected, the derivative time setting unit be-
comes the second.
• Even when hunting occurs for PID constants when auto-tuning is exe-
cuted in normal mode, it is less likely to occur when auto-tuning is exe-
cuted in RT Mode.
Section 3-8