70
Setting Control Specifications
Section 5-3
• 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.
• Derivative action:
This control action produces an output that is propor-
tional to the rate of change of the input. Since propor-
tional control and integral control correct for errors in
the control result, the control system will be slow to
respond to sudden changes in temperature. The
derivative action performs a corrective action by
increasing the MV in proportion to the slope of the
temperature change.
• Effect of Changes to P (Proportional Band)
• Effect of Changes to I (Integral Time)
• Effect of Changes to D (Derivative Time)
Increased P
The curve rises gradually and the
settling time is long, but overshooting
is prevented.
Decreased P
Overshooting and hunting occur, but
the set point is reached quickly and
the temperature stabilizes.
Increased I
It takes a long time for the process
value to reach the set point. It takes
time to achieve a stable state, but
overshooting, undershooting, and
hunting are reduced.
Decreased I
Overshooting and undershooting
occur. Hunting occurs. The process
value rises quickly.
Increased D
Overshooting, undershooting, and
the settling time are reduced, but fine
hunting occurs on the changes them-
selves.
Decreased D
Overshooting and undershooting are
increased and it takes time for the
process value to reach the set point.
Set value
Set value
Set value
Set value
Set value
Set value
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Страница 1: ...USER S MANUAL Modular Temperature Controllers for Gradient Temperature Control EJ1G Cat No H143 E1 01 ...
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Страница 53: ...32 Unit Configuration Examples Section 2 4 ...
Страница 69: ...48 Changing SPs During Operation Section 3 3 ...
Страница 81: ...60 Other Functions Section 4 5 ...
Страница 145: ...124 Other HFU Functions Section 5 7 ...
Страница 167: ...146 Detailed Description of Services Section 6 4 ...
Страница 189: ...168 Determining the Error from the Current Situation for Heater Burnout Alarm Errors Section 7 8 ...
Страница 229: ...208 Parameters That Can Be Allocated for Programless Communications Appendix ...
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