Adjusting The Speed Control Gain (Pr.820, Pr.821, X44 Signal) - Mitsubishi Electric FR-E700EX Instruction Manual

Speed control
4.4.3

Adjusting the speed control gain (Pr.820, Pr.821, X44 signal)

Manual adjustment of gain is useful to exhibit the optimum performance of the machine or to improve unfavorable

conditions such as vibration and acoustic noise during the operation with high load inertia or gear backlashes.
Parameter
Name
number
Speed control
820
P gain
Speed control
821
integral time
The above parameters can be set when Pr.160 Extended function display selection = "0". (Refer to page 182)
(1) Control block diagram
Pr.820 Speed control P gain
+
Speed
command
-
(2) P/PI switchover (X44 signal)
 By turning the P/PI control switching signal (X44) ON/OFF, you can select whether to add the integral time (I) or not
when performing gain adjustment with P gain and integral time. Under position control, the X44 signal is invalid. (PI
control is constantly valid.)
When the X44 signal is OFF ............PI control
When the X44 signal is ON ..............P control
 For the terminal used for X44 signal input, set "44" in any of Pr.178 to Pr.184 (input terminal function selection) to assign
the function.
(3) Adjusting the speed control gain manually
 The speed control gain can be adjusted for the conditions such as abnormal machine vibration, acoustic noise, slow
response, and overshoot.
Speed response of
the motor alone
200rad/s
30rad/s
15% 100%
80
Initial value
0.75K or
100%
lower
0 to 1000%
1.5K or
15%
higher
0.75K or
0.2s
lower
1.5K or
0.333s
higher
Speed
proportional
operation
Pr.821 Speed control integral time
X44
Estimated speed
0
X44
 Pr.820 Speed control P gain higher speeds up the response, but setting this too
high causes vibration and acoustic noise.
 Setting Pr.821 Speed control integral time lower shortens the return time to the
original speed at a speed fluctuation, but setting it too low causes overshoot.
Pr.820
Setting
Setting
range
The proportional gain during speed control is set. (Setting this
parameter higher improves the trackability for speed command
changes. It also reduces the speed fluctuation due to a load
fluctuation.) 100% is equivalent to 200rad/s.
The integral time during speed control is set. (Setting this parameter
0 to 20s lower shortens the return time to the original speed when the speed
fluctuates due to a load fluctuation.)
+
+
Speed
integral
operation
Integration
cleared to 0
Speed estimator
Operation
Torque
Motor
control