Speed Varies During Operation; Operation Mode Is Not Changed Properly; Operation Panel Display Is Not Operating; Parameter Write Cannot Be Performed - Mitsubishi Electric FR-E720-600 Instruction Manual

5.5.9

Speed varies during operation

When slip compensation is set under general-purpose magnetic flux vector control, or advanced magnetic flux vector
control is exercised, the output frequency varies with load fluctuation between 0 and 2Hz. This is a normal operation
and is not a fault.
1) Inspection of load
Check that the load is not varying.
2) Check the input signals
Check that the frequency setting signal is not varying.
Check that the frequency setting signal is not affected by noise. Set filter to the analog input terminal using Pr. 74
Input filter time constant.
Check for a malfunction due to undesirable currents when the transistor output unit is connected. (Refer to page
24)
3) Others
Check that the value of Pr. 80 Motor capacity and Pr. 81 Number of motor poles are correct to the inverter capacity and
motor capacity under advanced magnetic flux vector control and general-purpose magnetic flux vector control.
Check that the wiring length is not exceeding 30m (98.42 feet) when advanced magnetic flux vector control or
general-purpose magnetic flux vector control is exercised. Perform offline auto tuning. (Refer to page 113).
Check that the wiring length is not too long for V/F control.
Change the Pr. 19 Base frequency voltage setting (about 3%) under V/F control.

5.5.10 Operation mode is not changed properly

If the operation mode does not change correctly, check the following:
1) External input signal
2) Parameter setting
Check the Pr. 79 setting.
When the Pr. 79 Operation mode selection setting is "0" (initial value), the inverter is placed in the external
operation mode at input power-on. At this time, press
parameter unit (FR-PU04/FR-PU07) is used) to switch to the PU operation mode. For other values (1 to 4, 6, 7),
the operation mode is limited accordingly.
Check that the operation location by Pr. 550 and Pr. 551 is correct. (Example: write from the operation panel is
disabled when USB is connected)
(Refer to page 259).

5.5.11 Operation panel display is not operating

Check that wiring is securely performed and installation is correct.
Make sure that the connector is fitted securely across terminals P-P1.

5.5.12 Parameter write cannot be performed

Make sure that operation is not being performed (signal STF or STR is not ON).
Make sure that you are not attempting to set the parameter in the external operation mode.
Check Pr. 77 Parameter write selection.
Check Pr. 161 Frequency setting/key lock operation selection.
Check that the operation location by Pr. 550 and Pr. 551 is correct. (Example: write from the operation panel is
disabled when USB is connected)
(Refer to page 259).
Check first when you have some troubles
Check that the STF or STR signal is off. When it is on, the operation mode cannot be
changed.
on the operation panel (press when the
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