Mitsubishi Electric FR-A700 Instruction Manual page 390

Acceleration and deceleration
Optimum acceleration/deceleration mode (Pr. 292 = 3)
● 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 acce-
leration/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.
● 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 paramter unit.
Number of Optimum
Value Changes
1 to 3 times
4 times or more
Tab. 6-42: Storage of optimum values
● 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. Since the
stored optimum values are used for the next operation, faults, e.g. acceleration/deceleration
is not made if conditons change, alarm stop is made due to overcurrent protective function,
may occur.
NOTES 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 opti-
mum 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 cur-
rent, optimum acceleration/deceleration mode will not function.
6 - 210
Pr. 0, Pr. 7, Pr. 8
EEPROM value
Updated
Unchanged from third
value
RAM value
Updated
Updated
Parameter
Optimum Conditions
Updated
Updated