Mitsubishi Electric FR-A720-0.4K Instruction Manual page 192

(2) Optimum acceleration/deceleration mode (Pr. 292 = "3", Pr. 293)
⋅ The optimum operation within the rating range where the inverter can be continuously used regardless of the
inverter capability is performed.
Automatically set torque boost and acceleration/deceleration time so that the average current during acceleration/
deceleration is the rated current by the self-learning of the inverter.
It is appropriate for applications such as automatic transfer machine, etc. which is small in load change and is
operated in a predetermined pattern.
⋅ At the initial time when the optimum acceleration/deceleration mode has been selected, operation is performed at
the values set in Pr. 0 Torque boost, Pr. 7 Acceleration time and Pr. 8 Deceleration time. After operation, the average
current and peak current are calculated from the motor current during acceleration/deceleration. These values are
compared with the reference current (initial value is rated inverter current) and calculated, then more appropriate
values are set in Pr. 0, Pr. 7 and Pr. 8.
After that, operation is performed under the conditions of Pr. 0, Pr. 7 and Pr. 8 set, and more appropriate values are
calculated.
Note that the Pr. 0 value will not change under Advanced magnetic flux vector control, Real sensorless vector
control or vector control.
⋅ When overvoltage fault (E.OV3) occurs at deceleration, the Pr. 8 setting value becomes 1.4 times larger.
⋅ Storage of parameters
The optimum values of Pr. 0, Pr. 7 and Pr. 8 are written to both the
parameter RAM and EEPROM only three times of acceleration/
deceleration after the optimum acceleration/deceleration mode
has been selected or after the power is switched ON or the
inverter is reset. At of after the fourth attempt, they are not
stored into EEPROM. Hence, after power-on or inverter reset,
the values changed at the third time are valid. Note that the
values changed at the fourth or later time are calculated to
optimum and the values of Pr. 0, Pr. 7 and Pr. 8 are set to RAM,
the values can be stored into EEPROM by reading and writing
the values with the operation panel and parameter unit.
⋅ Either acceleration or deceleration can be made in the optimum acceleration/deceleration mode using Pr. 293
Acceleration/deceleration separate selection.
When the setting value is "0" (initial value), both acceleration and deceleration are made in the optimum
acceleration/deceleration mode.
⋅ It is inappropriate for machines which change in load and operation conditions.
Optimum values are saved for the next operation. If the operating condition changes before the next operation, a
fault such as overcurrent trip or a lack of acceleration/deceleration may occur.
REMARKS
⋅ If shortest acceleration/deceleration mode has been selected, inputting the jog signal (jog operation), RT signal (second
function selection) or X9 signal (third function selection) during an inverter stop will switch to the normal operation and give
priority to jog operation, second function selection or third function selection. Note that JOG and RT signal input is invalid even
if JOG signal and RT signal are input during operation in shortest/optimum acceleration/deceleration mode.
⋅ Because of the learning system, this mode is not valid at the first operation after the optimum acceleration/deceleration mode is set.
⋅ The optimum value are operated on only when acceleration is made from a stop to 30Hz or more or when deceleration is made
from 30Hz or more to stop.
⋅ When the motor is not connected or output current is less than 5% of the rated inverter current, optimum acceleration/
deceleration mode will not function.
⋅ Even when the optimum acceleration/deceleration mode is selected and Pr. 293 = "1" (acceleration only for the optimum
acceleration/deceleration mode), overvoltage fault (E.OV3) occurrence at deceleration makes the Pr. 8 setting value be set
again longer.
Setting of acceleration/deceleration time
and acceleration/deceleration pattern
Number of Pr. 0, Pr. 7, Pr. 8
Optimum
EEPROM
Value
value
Changes
1 to 3 times Updated Updated
Unchanged
4 or more
from third Updated
times
value
Optimum
RAM
Conditions
value
Updated
Updated
4
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