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Special Operation And Frequency Control; Pid Control (pr. 127 To Pr. 134) - Mitsubishi Electric FR-E720-0.1K(SC) Instruction Manual

Fr-e700 series.
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Special operation and frequency control

4.21 Special operation and frequency control
Purpose
Perform process control such as
pump and air volume.
Dancer control
Frequency control appropriate for
load torque
Avoid overvoltage alarm due to
regeneration by automatic
adjustment of output frequency

4.21.1 PID control (Pr. 127 to Pr. 134)

The inverter can be used to exercise process control, e.g. flow rate, air volume or pressure.
The terminal 2 input signal or parameter setting is used as a set point and the terminal 4 input signal used as a
feedback value to constitute a feedback system for PID control.
Parameter
Name
Number
PID control automatic
127
switchover frequency
128
PID action selection
129 ∗1
PID proportional band
130 ∗1
PID integral time
131
PID upper limit
132
PID lower limit
133 ∗1
PID action set point
134 ∗1
PID differential time
The above parameters can be set when Pr. 160 User group read selection ="0". (Refer to page 188)
∗1
This parameter allows its setting to be changed during operation in any operation mode even if "0" (initial value) is set in Pr. 77 Parameter write selection.
246
Parameter that should be Set
PID control
PID control (dancer control
setting)
Droop control
Regeneration avoidance
function
Initial
Setting
Value
Range
0 to 400Hz Frequency at which the control is automatically changed to PID control.
9999
9999
Without PID automatic switchover function
0
PID action is not performed
20
PID reverse action
21
PID forward action
40
PID reverse action
41
PID forward action
0
42
PID reverse action
43
PID forward action
50
PID reverse action
51
PID forward action
60
PID reverse action
61
PID forward action
If the proportional band is narrow (parameter setting is small), the
manipulated variable varies greatly with a slight change of the
0.1 to
measured value. Hence, as the proportional band narrows, the
100%
1000%
response sensitivity (gain) improves but the stability deteriorates, e.g.
hunting occurs. Gain Kp= 1/proportional band
9999
No proportional control
When deviation step is input, time (Ti) is the time required for integral (I)
0.1 to
action to provide the same manipulated variable as the proportional (P)
1s
3600s
action. As the integral time decreases, the set point is reached earlier
but hunting occurs more easily.
9999
No integral control.
Maximum value
0 to
If the feedback value exceeds the setting, the FUP signal is output. The
9999
100%
maximum input (20mA/5V/10V) of the measured value (terminal 4) is
equivalent to 100%.
9999
No function
Minimum frequency
0 to
If the process value falls below the setting range, the FDN signal is
9999
100%
output. The maximum input (20mA/5V/10V) of the measured value
(terminal 4) is equivalent to 100%.
9999
No function
0 to 100% Used to set the set point for PID control.
9999
9999
Terminal 2 input is the set point.
For deviation ramp input, time (Td) required for providing only the
0.01 to
manipulated variable for the proportional (P) action. As the differential
9999
10.00s
time increases, greater response is made to a deviation change.
9999
No differential control.
Pr. 127 to Pr. 134
Pr. 44, Pr. 45, Pr. 128 to Pr. 134
Pr. 286, Pr. 287
Pr. 882, Pr. 883, Pr. 885, Pr. 886
Description
Measured value (terminal 4)
Set value (terminal 2 or Pr. 133)
For dancer control
Addition
set point (Pr. 133),
method: fixed
measured value (terminal 4)
Addition
main speed (frequency command
method: ratio
of the operation mode)
Deviation value signal input (L
communication)
Measured value, set point input (L
Link communication)
Refer to Page
246
253
260
261
W
, CC-Link
ON
ORKS
W
, CC-
ON
ORKS

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