YOKOGAWA UT130 Technical Information

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6-7
TI 05C01E02-01E 1st Edition : Oct. 31, 2001-00
6.5.2 Manually Tuning PID Constants
•
PID based output can be obtained by
the equation on the left. Take this into
account when tuning PID parameters.
Manual PID tuning procedure is as
described in (2) to (5) on the left.
•
Procedure for manually tuning PID constants
(1) In principle, auto tuning must be used.
(2) Turn PID parameters in the order of P, I, D. Adjust a numeric slowly by observing
the result, and keep notes of what the progress is.
(3) Gradually reduce P from a larger value. When the measured value begins to
oscillate, stop tuning and increase the value somewhat.
(4) Also gradually reduce I from a larger value. When the measured value begins to
oscillate (with long period), stop tuning and increase the value somewhat.
(5) Gradually increase D from a smaller value. When the measured value begins to
oscillate (with short period), stop tuning and lower the value slightly.
Output =
P
Temperature
input span
e +
T
1
I
兰
edt
+PV
T
D
dt
d
e : Deviation
T
I
: Integral time
T
D
: Derivative time
P :
Proportional band
PV: Measured input value
6.5.3 PID Auto-Tuning
•
The temperature controller
automatically measures the process
characteristics and sets PID constants,
which are control parameters, to
optimum values for the setpoint.
•
Auto-tuning can be executed using
simple key operations.
•
When auto-tuning starts, the
temperature controller becomes an
ON/OFF controller, with its output
alternating between 100% and 0%.
•
Auto-tuning time is different according
to the process.
The longest time is 24 hours.
Do not use auto-tuning in the following
processes:
• Fast-response processes such as
pressure and flow
• Processes in which control output
ON/OFF switching is inappropriate
•
Auto-tuning (AT)
• Automatic PID constant setting function
• Uses a limit cycle method
The auto-tuning temporarily executes ON/OFF control, calculates appropriate PID
constants from response data obtained, and sets these constants.
Auto-tuning in progress
(OUT lamp flashing)
Auto-tuning ends
at third peak.
PID control using PID
constants calculated from
the AT results
3 times of ON/OFF control in steps
AT = ON
SP
Control
output

YOKOGAWA UT130 Specifications

General

Brand	YOKOGAWA
Model	UT130
Category	Temperature Controller
Language	English