Default: 65,535
Range: 0 to 65,535 (position units per second per millisecond)
Note: This parameter is available in RMC100 CPU firmware dated 20020222 or later.
This parameter is available on analog Position and Velocity Reference axes and configures the position filter. For reference axes, the Actual Position status field reflects the actual reading from the transducer, and the Target Position reflects the filtered position, after applying the Filter Time Constant, Deadband, Velocity Limit, and Acceleration Limit parameters. This parameter limits the rate of change of the Target Velocity to the this parameters value in position units per second per millisecond.
For example, suppose that the Actual Position jumps from 4100 to 4500 position units. Using a non-zero Filter Time Constant and the Velocity Limit, but with the Acceleration Limit set to a high value (such as 65,535), the Target Position would be computed as follows:
By lowering the Acceleration Limit parameter, the Target Position changes to the following:
Notice that the Target Position was smoothed at the start of the step jump by limiting the acceleration of the Target Position.
The Acceleration Limit is ignored if the position filter is disabled through the Filter Time Constant parameter.
The Acceleration Limit parameter must be at least equal to the Velocity Limit (in pos-units/sec) divided by twice the Filter Time Constant (in ms). For example, with a Filter Time Constant of 2 ms and a Velocity Limit of 1000 position units per second, the minimum Acceleration Limit will be 250. This limit is introduced because lower values for the Acceleration Limit would result in the Target Position overshooting the Actual Position significantly.
This and the other position filter parameters can also be changed through the Reference (W) command.
For details on reference axis filtering, see Reference Axis Filtering.
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