Omron CJ1W-NC271 - 12-2009, Operation Manual

Page: 308 / 687

280
Acceleration and Deceleration Operations
Section 7-4
To create a more precise setting unit for accelerations/decelerations, increase
the resolution of the command unit (i.e., increase the number of digits).
Example
If the command unit is 0.1 mm, the target speed is 1,000 mm/s (1,000.0 mm/s
= 10,000 command units/s) and the target speed must be reached in 250 ms,
the acceleration constant would be set to 4, as shown below.
1000 [command units/s]/250 [ms] = 40,000 [command units/s
2
]
= 4 [10,000 command units/s
2
]
If the acceleration constant is increased or decreased by only 1, the accelera-
tion time required to reach the same target speed is greatly affected, as
shown below:
Acceleration constant = 3:10000 [command units/s]/3 [10,000 command
units/s
2
] = 333 [ms]
Acceleration constant = 5:10000 [command units/s]/5 [10,000 command
units/s
2
] = 200 [ms]
If the precision of the command unit is increased by 2 digits to 0.001 mm, the
acceleration constant would be set to 400 to reach the same target speed of
1,000 mm/s (1000.000 mm/s = 1,000,000 command units/s) in the same time
of 250 ms.
1,000,000 [command units/s]/250 [ms] = 4,000,000 [command units/s
2
]
= 400 [10,000 command units/s
2
]
If the acceleration constant is increased or decreased by 1, the acceleration
time required to reach the same target speed is affected very little, as shown
below:
Acceleration constant = 399:1000000 [command units/s]/399 [10000 com-
mand units/s
2
] = 250.6 [ms]
Acceleration constant = 401:1000000 [command units/s]/401 [10000 com-
mand units/s
2
] = 249.3 [ms]
7-4-3 Acceleration/Deceleration Filter Settings
When a W-series Servo Drive is connected, acceleration/deceleration filters
can be set for each axis to avoid rapid changes in acceleration or decelera-
tion. A acceleration/deceleration filter can be set for each axis to enable non-
linear acceleration/deceleration curves. Using an acceleration/deceleration fil-
ter enables an exponential acceleration/deceleration curve and accelera-
tion/deceleration S-curves using a movement (running) average.
The G5-series Servo Drives and the G-series Servo Drives do not support
exponential filters, but acceleration/deceleration S-curves using a moving
average can be used.
The SMARTSTEP Junior Servo Drives do not support acceleration/decelera-
tion filters and the filters cannot be set.
To use the acceleration/deceleration filter, set the acceleration/deceleration
curve designation in the Axis Operating Output Memory Area when specifying
the operating command as well as setting the acceleration/deceleration filter
settings in the Servo Parameters.