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80
Setting Control Specifications
Section 4-3
Self-tuning (ST)
Self-tuning (ST) finds the PID constants by using step response tuning (SRT)
when the EJ1 is operated or the set point is changed.
Once the PID constants have been calculated, ST does not execute when the
next control operation is started as long as the set point remains unchanged.
Note
(1) Settings can only be made when Unit is stopped.
(2) The decimal point position is determined by the sensor selection. In this
case, however, the 0 (****) decimal point position setting will be treated as
setting 1 (***.*).
When using self-tuning, turn ON the power for the EJ1 and the power for the
load (e.g., a heater) simultaneously, or turn ON the power for the load first. If
the power is turned ON for the EJ1 before turning ON the power for the load,
self-tuning will not be performed properly and optimum control will not be
achieved.
Starting Conditions
Self-tuning by step response tuning (SRT) is started at the start of operation
and when the set point is changed when the following conditions are met.
Set point
Process
value
Autotuning starts
Autotuning completed
Limit Cycle
MV Amplitude 100%
Time
V1.2
Variable type
Parameter name
Setting range
Default
E5/A5 ST
(Channel) 0:
Disabled
1: Enabled
0
ST Stable Range
(Channel)
−
0.1 to 999.9 EU
(See note 2.)
15.0
Conditions for use
The input type must be set to temperature input, control output
must be assigned and set to standard control, the control
method must be set to 2-PID control, remote SP must be dis-
abled, and the Output ON Scheduling function must be dis-
abled.
At start of operation
When the set point is changed
1. The set point at the start of operation
differs from the set point when the pre-
vious SRT was executed. (See note 1.)
2. The difference between the tempera-
ture at the start of operation and the set
point is greater than the higher value of
either of the following: (Present propor-
tional band 1.27 + 4
°
C) or the ST stable
range.
3. The temperature at the start of opera-
tion is lower than the set point during re-
verse operation, and is larger than the
set point during direct operation.
4. There is no reset from input errors.
1. The new set point differs from the set
point used when the previous SRT was
executed. (See note 1.)
2. The set point change width is greater
than the larger value of either of the fol-
lowing: (Present proportional band 1.27
+ 4
°
C) or the ST stable range.
3. During reverse operation, the new set
point is larger than the set point before
the change; and during direct opera-
tion, the new set point is smaller than
the set point before the change.
4. The temperature is in a stable state
(See note 2). (An equilibrium state is
acceptable when the output is 0% at the
time the power is turned ON. ((See note
3.))
Summary of Contents for EJ1 EtherCAT
Page 2: ...EJ1 Modular Temperature Controllers User s Manual Revised July 2008 ...
Page 3: ...iv ...
Page 19: ...xx ...
Page 213: ...188 Detailed Description of Services Section 6 4 ...
Page 227: ...202 Detailed Description of Services Section 7 5 ...
Page 303: ...278 Index ...
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