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66
Setting Control Specifications
Section 4-3
■
Three-position Control
In heating/cooling control, a dead band area can be set where the MV is 0%
for both heating and cooling. with a dead band, 3-position control can be
achieved.
2-PID Control (Two-
degrees-of-freedom
PID)
The proportional band (P), integral time (I), and derivative time (D) must be
set for 2-PID control.
■
PID Settings
When the control characteristics are unknown, perform autotuning (AT) or
self-tuning (ST with
). When AT (or ST with
) is executed, the opti-
mum PID constants for the set point at that time are set automatically.
When the control characteristics are already known, the PID parameters can
be set directly to adjust control. The PID parameters are set with the Propor-
tional Band (P), Integral Time (I), and Derivative Time (D) parameters.
Note
Refer to
4-3-8 Tuning
for details on autotuning or self-tuning (ST
with ).
Note
(1) Refer to
4-7-1 Bank Function
for details on banks.
(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 (***.*).
• Proportional action: In proportional action, the MV is proportional to the
deviation (control error).
• Integral action:
This control action produces an output that is propor-
tional to the time integral of the control error. An off-
set normally occurs in proportional control, so
proportional action is used in combination with inte-
gral action. As time passes, this offset disappears
and the control temperature (process value) matches
the set point.
OFF
ON
PV
Heating side
Hysteresis (Cooling)
Hysteresis (Heating)
Dead band
Cooling side
Set point
Variable type
Parameter name
Setting range
Default
D0/90
Proportional Band
(BANK) 0.1 to 999.9 EU
(See note 1.)
8.0
Integral Time
(BANK) 0 to 3999 Seconds
233
Derivative Time
(BANK) 0.0 to 999.9 Seconds
40.0
Conditions for use
The control method must be set to 2-PID control.
V1.2
V1.2
V1.2
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 ...
Page 305: ......