4.19 Special Operation And Speed Control; Pid Control (Speed Control) (Pr.127 To Pr.134) - Mitsubishi Electric FR-E700EX Instruction Manual

4.19 Special operation and speed control

Purpose
To perform process control such as
pump and air volume
To avoid overvoltage alarm due to
regeneration by automatic
adjustment of output speed

4.19.1 PID control (Speed control) (Pr.127 to Pr.134)

The drive unit 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 speed
128 PID action selection
129 PID proportional band

130 PID integral time

131 PID upper limit
132 PID lower limit
133 PID action set point

134 PID differential time

The above parameters can be set when Pr.160 Extended function display selection = "0". (Refer to page 182)

Pr.129, Pr.130, Pr.133 and Pr.134 can be set during operation. These can also be set independently of the operation mode.

When a value exceeding 3000 r/min is set, the rotation speed will be limited at 3000 r/min.
Also, when an S-PM geared motor is used, the maximum setting value differs depending on the drive unit capacity. (0.2 to 2.2K: 12000 r/min, 3.7K: 8000 r/
min)
Special operation and speed control
Parameter to set
PID control
Regeneration avoidance
function
Initial Setting
value range
0 to 4800r/min 
9999
9999
0
20
21
0 50
51
60
61
0.1 to 1000%
100%
9999
0.1 to 3600s
1s
9999
0 to 100%
9999
9999
0 to 100%
9999
9999
0 to 100%
9999
9999
0 to 100%
9999
9999
Pr.127 to Pr.134
Pr.882, Pr.883, Pr.885, Pr.886
Description
Speed at which the control is automatically changed to PID
control.
Without PID automatic switchover function
PID action is not performed
PID reverse action Measured value (terminal 4)
PID forward action
Set value (terminal 2 or Pr.133)
PID reverse action Deviation value signal input (CC-Link
PID forward action
PID reverse action Measured value, set point input (CC-
PID forward action Link communication)
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
No proportional control
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.
No integral control.
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%.
No function
Minimum frequency
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%.
No function
Used to set the set point for PID control.
Terminal 2 input is the set point.
For deviation ramp input, time (Td) 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.
No differential control.
Refer to page
235
242
communication)
4
235