MX80L Series Product Manual
Chapter 4 - Performance
Parker Hannifin Corporation
Daedal Division
Irwin, Pennsylvania
36
Chapter 4 - Performance
Acceleration Limits
Acceleration of linear servo driven tables is typically limited by three
(3)
factors; linear bearings,
available motor force and settling time. Due to the high load bearings used in the MX80, the
acceleration is only limited by the available motor force and the settling time.
•
Available Motor Force
This is the primary factor that reduces acceleration. This is simply the amount of motor force
available to produce acceleration. The larger the inertial and or frictional load the lower the
accelerations limit.
•
Settling Time
In many applications reducing cycle time is a primary concern. To this end, the “settling” time (the
amount of time needed after a move is completed for table and load oscillating to come within
acceptable limits) become very important. In many cases where very small incrementing moves are
executed, the settling time is greater than the actual move time. In these cases accelerations may
need to be reduced thus reducing the settling time.
Speed Limits
The Maximum Speed of the MX80L is limited by three (3) factors:
•
Travel Length
The short travel length of the MX80L is the main limiting factor for maximum speed. The T01 and
T02 options (25mm and 50mm) a triangular motion profile with 5g accel/decel will only yield peak
speeds of 1.1m/sec and 1.5 m/s respectively.
•
Linear Encoder Limit
The linear encoder has speed limits relative to encoder resolution; these limits are listed below:
Encoder
Resolution
Maximum Velocity
Required Post
Quadrature Input
Bandwidth (²)
5 micron
5 meters/second (¹)
2 MHz
1 micron
3 meters/second(1)
6.7 MHz
0.5 micron
1.5 meters/second
6.7 MHz
0.1 micron
0.3 meters/second
10 MHz
0.02 micron
0.06 meters/second
10 MHz
0.01 micron
0.03 meters/second
10 MHz
(¹) When using an encoder with 5 micron resolution, velocity limited by speed dependant force.
(²) This is the bandwidth frequency that the amplifier or servo control input should have to operate properly with the encoder output at
maximum speeds. This frequency is post-quadrature, to determine pre-quadrature divide above values by 4. Above frequencies include a
safety factor for encoder tolerances and line loses.
•
Force / Speed Limit
The available force of the MX80L reduces as speed increases.
(Chapter 2,
MX80L Series Technical Data
)
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