Character: T
Decimal: 84
Hexadecimal: 0x54
Command Value: 0 to end segment, otherwise point interval
Set Spline Interval (non-zero command value)
If the command value is non-zero, then this command stores that command value as the current interval between spline points. The units for this interval depend on the presence of the Sensor Digital I/O. If the Sensor Digital I/O is present, then the interval is in terms of counter ticks (either quadrature or edge counter). If it is not present, then the interval is in terms of milliseconds. As spline points are added, they use the current interval value as the time between the added point and the next one to be added. The minimum value for an interval is 5 units and the maximum interval is 65535 units.
This command will fail only when a value between 1 and 4 is used. These small intervals tend to create unrealistic accelerations and are therefore not allowed. This error is indicated by the Parameter Error bit in the Status word:
End Spline Segment (zero command value)
When the command value is zero, this command will perform final calculations on the spline points in a segment. After each segment is added, a ’r;T’ command with a command value of 0 must be sent. Any points sent after this ’r;T’ command will belong to the next spline segment.
When used to perform final calculations, this command may not finish immediately. This command will process up to four points immediately. If more points are in the segment, then an additional control loop will be required for every seven points in the segment. Therefore, a 50-point segment on a module with a one-millisecond control loop time will require eight (8) milliseconds to process. The Acknowledge bit of the Status word will toggle when this command is completed.
This command will fail when using a zero command value for the following reasons, as indicated by the Parameter Error bit in the Status word:
No spline points have been added since the last spline segment.
Only 1 spline point has been added since the last spline segment.
The spline generated an unrealistic acceleration or speed that would have caused an overflow. If this happens the spline segment is invalid. The limit for speed is from 0 to 65535 position units per second. The limit for acceleration is -512 to 511 position units per second per second. If position units are thousandths of inches then this would translate to 511 inches per second per second, or about 1.25 G’s.
Another command is issued before the Acknowledge Bit of the Status word is toggled. Notice that this is not indicated by the Parameter Error bit.
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