Mitsubishi Electronics FR-F700-NA ユーザーズマニュアル
281
PID control
4
4.20.4 Second PID function (Pr.753 to Pr. 758, Pr.765 to Pr.769)
When the RT signal is ON and Pr. 753 Second PID action selection
≠ 9999, PID control is commanded by the
second function parameters.
When Pr. 753 = 9999, normal PID control is performed even if the second functions are valid.
When the control method is switched from the second PID control to the normal PID control, the integral value is
estimated. The integral value is estimated by calculating the integral term with the output frequency and the P
term. This method is same as when the control method changes to PID control when the frequency reaches the
automatic switchover frequency.
When Pr. 753 = 9999, normal PID control is performed even if the second functions are valid.
When the control method is switched from the second PID control to the normal PID control, the integral value is
estimated. The integral value is estimated by calculating the integral term with the output frequency and the P
term. This method is same as when the control method changes to PID control when the frequency reaches the
automatic switchover frequency.
Parameter
Number
Name
Initial
Value
Value
Setting
Range
Description
753
Second PID action
selection
selection
9999
PID reverse action
Deviation value signal input
(terminal 1
11, 111
PID forward action
20, 120
PID reverse action
Measured value (terminal 4
or Pr. 133)
21, 121
PID forward action
50
PID reverse action
Deviation value signal input
(L
ON
W
ORKS
, CC-Link, BACnet)
51
PID forward action
60
PID reverse action
Measured value, set point input
(L
ON
W
ORKS
, CC-Link, BACnet)
61
PID forward action
70
PID reverse action
Deviation value signal input
(PLC function)
71
PID forward action
80
PID reverse action
Measured value, set point input
(PLC function)
81
PID forward action
90
PID reverse action
Deviation value signal input
(PLC function)
(Not reflected to the inverter frequency)
91
PID forward action
100
PID reverse action
Measured value, set point input
(PLC function)
(Not reflected to the inverter frequency)
101
PID forward action
9999
Normal PID control is performed regardless of the second PID
control parameter settings.
control parameter settings.
754
Second PID control
automatic switchover
frequency
automatic switchover
frequency
9999
0 to 400Hz
Set the frequency at which the control is automatically
changed to PID control while the RT signals is ON.
changed to PID control while the RT signals is ON.
9999
Without second PID control automatic switchover function
755
Second PID action set
point
point
9999
0 to 100%
Set the set point for PID control, which is performed while the
RT signal is ON.
RT signal is ON.
9999
Terminal 2 input is the set point while the RT signal is ON.
756
Second PID
proportional band
proportional band
100%
0.1 to 1000%
Set the proportional band for PID control, which is performed
while the RT signal is ON.
If the proportional band is narrow (parameter setting is small),
the manipulated variable varies greatly with a slight change of
the measured value. Hence, as the proportional band narrows,
the response sensitivity (gain) improves but the stability
deteriorates, e.g. hunting occurs.
Gain Kp = 1/proportional band
while the RT signal is ON.
If the proportional band is narrow (parameter setting is small),
the manipulated variable varies greatly with a slight change of
the measured value. Hence, as the proportional band narrows,
the response sensitivity (gain) improves but the stability
deteriorates, e.g. hunting occurs.
Gain Kp = 1/proportional band
9999
Without second proportional band
757
Second PID integral
time
time
1s
0.1 to 3600s
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
integral (I) action to provide the same manipulated variable as
proportional (P) action.
As the integral time decreases, the set point is reached earlier
but hunting occurs more easily.
while the RT signal is ON.
When deviation step is input, time (Ti) is the time required for
integral (I) action to provide the same manipulated variable as
proportional (P) action.
As the integral time decreases, the set point is reached earlier
but hunting occurs more easily.
9999
Without second integral control
758
Second PID differential
time
time
9999
0.01 to
10.00s
10.00s
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.
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.
9999
Without second differential control