Delta RMC151 - Manual (Page 733)

8 Command Reference
When using s-curves, if the move command is re-issued when the axis is decelerating, it
may cause the axis to overshoot the requested position.
Starting from Open Loop
If the axis is in open loop when this command is issued, it will use the Actual Position and
Actual Velocity as the beginning Target Position and Target Velocity. Therefore, if the axis
is stopped in open loop and the Actual Velocity is bouncing around (which is common),
and the requested acceleration is low, it can take a long time to change the velocity to
the requested velocity, which may cause the Target Position to move in the opposite
direction before moving in the correct direction.
To avoid this problem, when starting from a stop in open loop, either use high
acceleration and deceleration values, or issue a Hold Current Position (5) command
before issuing the Move Absolute.
This also applies to other closed-loop position motion commands.
Status Bits
In Position Bit
When the Target Position reaches the Requested Position and the Actual Position is
within the In Position Tolerance window, the In Position Status bit will be set. This bit
indicates that the move is complete and the axis is at position.
Target Generator Bits
The Target Generator bits in the Status Bits register indicate which portion of the move
the axis is currently in. These bits are useful when programming complex motion
sequences.
Target Generator Done bit
This bit indicates that the Target Position has reached the Requested Position. Notice
that this bit does not indicate whether the Actual Position has reached the Requested
Position.
Target Generator State A and B bits
B
A Description
0 0 The target generator is complete
0 1 Acceleration
1 0 Constant Velocity
1 1 Deceleration
8.4.5.2. Command: Move Relative (21)
Supported Axes: Position Control Axes
Supported Control Modes: Position PID, Position I-PD
Firmware Requirement: 1.00 or newer
See the Commands Overview topic for basic command information and how to issue
commands from PLCs, HMIs, etc.
Command Parameters
# Parameter Description Range
1 Requested Distance (position-units) any
2 Requested Speed (position-units/s) ≥0
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