Rockwell Automation 1771-QB Linear Pos. - Manual (Page 79)

Interpreting ModuleĆtoĆPLC Data
(READS)
Chapter 6
6Ć18
the accuracy is degraded if the axis is unstable or if the velocity is extremely
low. Velocities at or above 10% of the maximum velocity work best.
the maximum velocities calculated by the module will not be accurate if
motion is impeded by physical obstructions.
the maximum velocity predictions will vary slightly for moves at different
velocities due to non-linearities in the hydraulic system. If it is critical that
the module perform best at a particular velocity, then that velocity should be
used to determine the optimal analog calibration constants. Otherwise, it is
best to use a moderately low velocity (10% of the maximum velocity) to
optimize the performance near the setpoint.