Mitsubishi Electric FR-F740 EC Instruction Manual page 182

Parameter overview
Parameter
Func-
Name
tion
Second PID control
754 automatic switchover
frequency
Second PID action set
755
point
Second PID
756
proportional band
Second PID integral
757
time
Second PID differential
758
time
759 PID unit selection
Tab. 6-1: Parameter overview (32)
6 - 32
Incre- Initial Setting
ments Value Range
0–400Hz
0.01Hz 9999
9999
0–100%
0.01% 9999
9999
0.1–1000%
0.1% 100%
9999
0.1–3600s
0.1s 1s
9999
0.01
–10.00s
0.01s 9999
9999
1 9999 0–43/9999
Description
Set the frequency at which the
control is automatically changed
to PID control while the RT signals
is ON.
Without second PID control auto-
matic switchover function
Set the set point for PID control,
which is performed while the RT
signal is ON.
Terminal 2 input is the set point
while the RT signal is ON.
Set the proportional band for PID
control, which is performed while
the RT signal is ON.
f the proportional band is narrow
(parameter setting is small), the
manipulated variable varies greatly
with a slight change of the meas-
ured value. Hence, as the propor-
tional band narrows, the response
sensitivity (gain) improves but the
stability deteriorates, e.g. hunting
occurs.
Gain Kp = 1/proportional band
Without second proportional band
Set the PID integral time for PID
control, which is performed while
the RT signal is ON.
When deviation step is input, time
(Ti) is the time required for inte-
gral (I) action to provide the same
manipulated variable as propor-
tional (P) action.
As the integral time decreases, the
set point is reached earlier but
hunting occurs more easily.
Without second integral control
Set the PID differential time for
PID control, which is performed
while the RT signal is ON.
When deviation lamp is input, time
(Td) is the time required to provide
the manipulated variable of only
the proportional (P) action.
As the differential time increases,
greater response is made to a
deviation change.
Without second differential control
Change the display unit of the
parameters and monitored items,
which are related to PID control.
Parameter
All
Para- Para-
para-
meter meter
meter
copy clear
Refer
clear
to
page
✔: enabled
—: disabled
✔ ✔ ✔
✔ ✔ ✔
✔ ✔ ✔
6-358
✔ ✔ ✔
✔ ✔ ✔
✔ ✔ ✔
6-346