Mitsubishi Electric FR-A700 Technical Manual page 209

(2) Optimum acceleration/deceleration mode
[Pr. 292 = 3]
A700
Automatic setting of [Pr. 0 Torque boost], [Pr. 7
Acceleration time] and [Pr. 8 Deceleration time] is
available. Set [Pr.
deceleration = 3] and repeat actual operation to
perform self learning of the inverter for proper current
during acceleration/deceleration.
1) Control method
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 for
increase or decrease, then more appropriate
values are set in [Pr. 0, 7, 8]. The calculated result
is set in [Pr. 0, 7, 8] as the optimum value.
After that, operation is performed with that [Pr. 0, 7,
8] setting, and more appropriate values are
calculated and set in [Pr. 0, 7, 8] as needed. Note
that the [Pr. 0] value will not change under
advanced magnetic flux vector control and real
sensorless vector control and vector control.
Therefore, by
automatically set the appropriate value regardless
of the initial value, and optimized acceleration/
deceleration operation is available. Calculation is
performed only when acceleration from a stop to
30.01Hz or more, or when deceleration from
30.01Hz 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.
2) Storage of appropriate parameter setting
The optimum values of [Pr. 0, 7, 8] are written to
both the parameter RAM and EEPROM only three
times 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, these are not stored into
EEPROM. Hence, after power-ON or inverter
reset, the values changed at the third time are
valid. Operation and display of the operation
panel is based on the latest optimum value.
The [Pr. 0, 7, 8] value changed at the fourth or later
time can be stored into EEPROM by reading and
writing the values with the operation panel.
Number of [Pr. 0], [Pr. 7], [Pr. 8]
Optimum EEPROM
Value Changes value
1 to 3 times Updated
Unchanged
4 or more times
from third value
292 Automatic acceleration
repeating operations will
Optimum
RAM value Conditions
Updated Updated
Updated Updated
3) Applications
Appropriate application
• For applications such as automatic transfer
machine, etc which is small in load change
and is operated in a predetermined pattern.
Inappropriate application
• For machines which change in load and
operation
optimum values are used for the next
operation,
condition causes miss setting, and results in
non acceleration/deceleration or fault due to
overcurrent protection function, etc.
4) Setting of dedicated parameters
By setting
application range can be made wider.
In the initial setting, 100% of the rated inverter
current is regarded as the optimum current value.
Since the [Pr. 61 to 63] settings automatically
return to the initial value (9999) if the [Pr. 292]
setting is changed, set [Pr. 292] first when you
need to set [Pr. 61 to 63].
[Pr. 61]:Set the current value (A) that is referenced
for optimum current value. When the motor
and inverter are different in capacity, for
example, and it is desired to define the
motor rating as reference, set the reference
current value in this parameter.
[Pr. 62]:Set the optimum current level (%) for
acceleration. Set when you want to restrict
average current at acceleration.
[Pr. 63]:Set the optimum current level (%) for
deceleration. Set when you want to restrict
average current at deceleration.
[Pr. 293]: Set to select the Optimum acceleration/
deceleration operation for only when
accelerating or decelerating.
243
PARAMETER
conditions. Since the
changing of the application
the dedicated parameters,
stored
the
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