216
Special operation and speed control
4.18 Special operation and speed control
4.18.1 PID control (Pr. 127 to Pr. 134, Pr. 553, Pr. 554, Pr. 575 to Pr. 577, C42 to C45)
Purpose
Parameter that should be Set
Refer to Page
Perform process control such as
pump and air volume.
PID control
Pr. 127 to Pr. 134, Pr. 553,
Pr. 554, Pr. 575 to Pr. 577,
C42 to C45
Avoid overvoltage alarm due to
regeneration by automatic
adjustment of rotation speed
Regeneration avoidance
function
Pr. 882, Pr. 883, Pr. 885, Pr. 886
The drive unit can be used to perform 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
Number
Name
Initial
Value
Setting
Range
Description
127
PID control
automatic switchover
speed
9999
0 to 12000r/min /
0 to 8000r/min
Speed at which the control is automatically changed to PID control.
9999
Without PID automatic switchover function
128
PID action selection
0
0
PID action is not performed
20
PID reverse action Measured value (terminal 4)
Set value (terminal 2 or
Pr. 133
)
21
PID forward action
129
PID proportional
band
100%
0.1 to 1000%
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, for
example, hunting occurs. Gain Kp= 1/proportional band
9999
No proportional control
130
PID integral time
1s
0.1 to 3600s
When deviation step is input, time (Ti) is the time required for integral
(I) action to provide the same manipulated variable as the proportional
(P) action. As the integral time decreases, the set point is reached
earlier but hunting occurs more easily.
9999
No integral control.
131
PID upper limit
9999
0 to 100%
Maximum value
If the feedback value exceeds the setting, the FUP signal is output.
The maximum input (20mA/5V/10V) of the measured value (terminal
4) is equivalent to 100%.
9999
No function
132
PID lower limit
9999
0 to 100%
Minimum speed
If the measured value falls below the setting range, the FDN signal is
output. The maximum input (20mA/5V/10V) of the measured value
(terminal 4) is equivalent to 100%.
9999
No function
133
PID action set point
9999
Used to set the set point for PID control.
9999
Terminal 2 input is the set point.
134
PID differential time
9999
0.01 to 10s
For deviation ramp input, time (Td) is required for providing only the
manipulated variable for the proportional (P) action. As the differential
time increases, greater response is made to a deviation change.
9999
No differential control.
553
PID deviation limit
9999
0 to 100.0%
Y48 signal is output when the absolute value of deviation amount
exceeds the deviation limit value.
9999
No function
554
PID signal operation
selection
0
0 to 3,
10 to 13
Select the operation to be performed at the detection of upper, lower,
and deviation limit for the measured value input. The operation for PID
output suspension function can be selected.
575
Output interruption
detection time
1s
0 to 3600s
The drive unit stops operation if the rotation speed after PID operation
remains at less than the
Pr. 576
setting for longer than the time set in
Pr.
575
.
9999
Without output interruption function
576
Output interruption
detection level
0r/min
0 to 12000r/min /
0 to 8000r/min
Set the speed at which the output interruption processing is
performed.
Summary of Contents for FR-D720-0.2K-G
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