Delta RMC151 - Manual (Page 123)

3 Controller Features
Each of the commands listed above has a Direction parameter with the following options
for rotary axes:
• Positive:
The axis will move to the Requested Position in the direction of increasing position
units. If the Command Position is less than the current Target Position, the axis will
wrap around to the Requested Position. If the Requested Position command
parameter is outside the valid range of the axis, the Command Position will be set
within the valid range using modular arithmetic such that the position will be the
same location within the range. For example, if the valid range is 0-360 (not
including 360), and the Requested Position is 800, the Command Position will be set
to 80 (800 mod 360). Likewise, with a Requested Position of -100, the Command
Position will be set to 260 (360 + (-100 mod 360)). The Command Position will
never be more than 1 revolution from the current Target Position.
Example:
Consider a rotary axis with a Position Unwind of 360 and a current Target
Position of 180. A move to 90 with the Positive Direction parameter will cause
the axis to pass 0 (wrap), and end at 90 position units.
• Negative:
The axis will move to the Requested Position in the direction of decreasing position
units. If the Command Position is greater than the current Target Position, the axis
will wrap around to the Requested Position. If the Requested Position command
parameter is outside the valid range of the axis, the Command Position will be set
within the valid range using modulo arithmetic such that the position will be the
same location within the range. For example, if the valid range is 0-360 (not
including 360), and the Requested Position is 800, the Command Position will be set
to 80 (800 mod 360). Likewise, with a Requested Position of -100, the Command
Position will be set to 260 (360 + (-100 mod 360)). The Command Position will
never be more than 1 revolution from the current Target Position.
Example:
Consider a rotary axis with a Position Unwind of 360 and a current Target
Position of 180. A move to 270 with the Negative Direction parameter will
cause the axis to pass 0 and end at 90 position units.
• Nearest:
The axis will move to the Requested Position in the direction that results in the
shortest distance of travel. If the Requested Position command parameter is outside
the valid range of the axis, the Command Position will be set within the valid range
using modulo arithmetic such that the position will be the same location within the
range. For example, if the valid range is 0-360 (not including 360), and the
Requested Position is 800, the Command Position will be set to 80 (800 mod 360).
Likewise, with a Requested Position of -100, the Command Position will be set to
260 (360 + (-100 mod 360)). The Command Position will never be more than 1
revolution from the current Target Position.
Example:
Consider a rotary axis with a Position Unwind of 360 and a current Target
Position of 180. A move to 270 with the Nearest Direction parameter will
cause the axis to go directly to 270. Likewise, with a current Target Position
of 45, a move to 270 with the Nearest Direction parameter will cause the axis
to pass 0 and go to 270.
• Absolute:
This option is very useful for moving the axis through multiple revolutions. With the
Absolute option, the Move command mimics a linear axis. The Requested Position
command parameter can be any value; it does not need to within the valid range
of the axis. When the command is issued, the value in the Requested Position
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