4.11 Frequency setting by external terminals
4.12.4 Shortest acceleration/deceleration and optimum acceleration/deceleration
(1) Shortest acceleration/deceleration mode (Pr. 292 = "1, 11", Pr. 293)
⋅ Set when you want to accelerate/decelerate the motor for the shortest time. It is desired to make acceleration/
deceleration in a shorter time for a machine tool etc. but the design values of machine constants are unknown.
⋅ Acceleration/deceleration speed is automatically adjusted at a start of acceleration/deceleration so that acceleration/deceleration is made with the maximum torque the inverter can output according to the setting value of Pr. 7 Acceleration time and Pr. 8 Deceleration time. (The setting values of Pr. 7 and Pr. 8 are not changed)
⋅ Either acceleration or deceleration can be made in the shortest time using Pr. 293 Acceleration/deceleration separate selection.
When the setting value is "0" (initial value), both acceleration and deceleration can be made in the shortest time.
⋅ Since the 7.5K or lower inverter has a built-in brake resistor, set Pr. 292 to "11". Set "11" also when a high-duty brake resistor or brake unit is connected. Deceleration time can be further shortened.
⋅ When the shortest acceleration/deceleration mode is selected under V/F control and Advanced magnetic flux vector control, the stall prevention operation level during acceleration/deceleration becomes 150% (adjustable using Pr. 61 to Pr. 63 ). The setting of Pr. 22 Stall prevention operation level and stall level by analog input are used only during a constant speed operation.
Adjustment using Pr. 61 to Pr. 63 cannot be made under Real sensorless vector control or vector control since torque limit level (Pr. 22 etc.) is used during acceleration/deceleration.
⋅ It is inappropriate to use for the following applications.
a)Machine with a large inertia such as a fan (more than 10 times). Since stall prevention operation will be activated for a long time, this type of machine may trip due to motor overloading, etc.
b)It is desired to always perform operation with a constant acceleration/deceleration time.
The inverter operates in the same conditions as when appropriate values are set in each parameter even if acceleration/deceleration time and V/F pattern are not set. This function is useful when you just want to operate, etc. without fine parameter setting.
Parameter
Number Name Initial
Value Setting Range Description
61 Reference current 9999
55K or
lower 0 to 500A
Set the reference current during shortest/ optimum acceleration/deceleration.
75K or
higher 0 to 3600A
9999 Rated inverter output current value is reference 62 Reference value
at acceleration 9999
0 to 220% Set the limit value/optimum value during shortest/
optimum acceleration.
9999 Shortest acceleration/deceleration: 150% is a limit value Optimum acceleration/deceleration: 100% is an optimum value
63 Reference value
at deceleration 9999
0 to 220% Set the limit value/optimum value during shortest/
optimum deceleration.
9999 Shortest acceleration/deceleration: 150% is a limit value Optimum acceleration/deceleration: 100% is an optimum value
292 Automatic acceleration/
deceleration 0
0 Normal operation mode
1 Shortest acceleration/deceleration mode (without brake)
11 Shortest acceleration/deceleration mode (with brake) 3 Optimum acceleration/deceleration mode
5, 6 Elevator mode1, 2 (Refer to page 163) 7, 8 Brake sequence mode 1, 2 (Refer to page 217.)
293
Acceleration/
deceleration separate selection
0
0 Both acceleration and deceleration are made in the shortest/optimum acceleration/deceleration mode 1 Only acceleration is made in the shortest/optimum
acceleration/deceleration mode
2 Only deceleration is made in the shortest/optimum acceleration/deceleration mode
REMARKS
⋅ Even if automatic 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
Setting of acceleration/deceleration time and acceleration/deceleration pattern
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(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.
⋅ 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.
⋅ 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.
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.
Number of Optimum
Value Changes
Pr. 0, Pr. 7, Pr. 8
Optimum Conditions EEPROM
value
RAM value
1 to 3 times Updated Updated Updated 4 or more
times
Unchanged from third value
Updated Updated
(3) Adjustment of shortest and optimum acceleration/deceleration mode (Pr. 61 to Pr. 63)
⋅ By setting the adjustment parameters Pr. 61 to Pr. 63, the application range can be made wider.
Parameter
Number Name Setting Range Description
61 Reference current
55K or
lower 0 to 500A For example, when the motor and inverter are different in capacity, set the rated motor current value.
Shortest acceleration/deceleration: Set reference current (A) of the stall prevention operation level during acceleration/deceleration Optimum acceleration/deceleration: Set reference current (A) of the optimum current during acceleration/deceleration
75K or
higher 0 to 3600A
9999 (initial value) The rated inverter current is defined as reference.
62 63
Reference value at acceleration Reference value at deceleration
0 to 220%
Set when it is desired to change the reference level of acceleration and deceleration.
Shortest acceleration/deceleration: Set the stall prevention operation level (ratio to the current value of Pr. 61 ) during acceleration/deceleration.
Optimum acceleration/deceleration: Set the optimum current level (ratio to the current value of Pr. 61 ) during acceleration/
deceleration.
(initial value)9999
Shortest acceleration/deceleration: The 150% value during shortest acceleration/deceleration is judged as the stall prevention operation level.
Optimum acceleration/deceleration: 100% is the optimum value REMARKS
⋅ Pr. 61 to Pr. 63 are invalid when Real sensorless vector control or vector control is selected in the shortest acceleration/
deceleration mode.
⋅ Since the Pr. 61 to Pr. 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 Pr. 63.
♦ Parameters referred to ♦ Pr. 0 Torque boost Refer to page 146
Pr. 7 Acceleration time, Pr. 8 Deceleration time Refer to page 172 Pr. 22 Stall prevention operation level Refer to page 152 Pr. 22 Torque limit level Refer to page 100
Selection and protection of a motor
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