Speed Does Not Accelerate; Unable To Write Parameter Setting - Mitsubishi Electric FR-D720-0.2K-G Instruction Manual

Check first when you have a trouble

5.5.12 Speed does not accelerate

Check
Points
Start command and speed command are chattering.
Input
The wiring length used for analog speed command is
Signal too long, and it is causing a voltage (current) drop.
Input signal lines are affected by external EMI.
Pr. 1, Pr. 2, calibration parameter C2 to C7 settings are
improper.
The maximum voltage (current) input value is not set
during the External operation. (Pr. 125, Pr. 126)
Parameter
Setting
Stall prevention function is activated due to a heavy
load.
Offline auto tuning is not performed when driving a
motor other than S-PM geared motor.
During PID control, rotation speed is automatically controlled to make measured value = set point.
Main
Brake resistor is connected between terminal P/+ and
Circuit P1 by mistake.

5.5.13 Unable to write parameter setting

Check
Points
Input
Operation is being performed (signal STF or STR is
Signal ON).
You are attempting to set the parameter in the External
operation mode.
Parameter is disabled by the Pr. 77 Parameter write
Parameter
selection setting.
Setting
Key lock is activated by the Pr. 161 Speed setting/key lock
operation selection setting.
Operation mode and a writing device do not
correspond.
270
Possible Cause
Possible Cause
Countermeasures
Check if the start command and the speed command
are correct.
Perform analog input bias/gain calibration.
Take countermeasures against EMI, such as using
shielded wires for input signal lines.
Check the settings of Pr. 1 Maximum setting and Pr. 2
Minimum setting.
Check the calibration parameter C2 to C7 settings.
The maximum speed is limited to the maximum speed of
the PM motor.
Check the Pr. 125 Terminal 2 speed setting gain speed and
Pr. 126 Terminal 4 speed setting gain speed settings.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level higher according
to the load. (Setting Pr. 22 too large may result in
frequent overcurrent trip (E.OC).)
Check the capacities of the drive unit and the motor.
Perform offline auto tuning.
Connect an optional brake transistor (MRS type, MYS
type, FR-ABR) between terminal P/+ and PR.
Countermeasures
Stop the operation.
When Pr. 77 = "0" (initial value), write is enabled only
during a stop.
Choose the PU operation mode.
Or, set Pr. 77 = "2" to enable parameter write regardless
of the operation mode.
Check Pr. 77 Parameter write selection setting.
Check Pr. 161 Speed setting/key lock operation selection
setting.
Check Pr. 79, Pr. 338, Pr. 339, Pr. 551, and select an
operation mode suitable for the purpose.
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