User`s manual

Functions
5
5-42
5. Functions
5.15 Fast positioning function
The fast positioning function shortens the positioning settling time to the minimum time,
and drastically reduces the positioning deviation that occurs during positioning
operation.
Note 1: The Moment of inertia (Fd-00) parameter must be set correctly to use this
function.
Note 2: When setting this function to improve the tact time, the following parameters
also need to be adjusted.
• Speed control cut-off frequency (Fd-01)
• Speed control proportional gain (Fd-02)
• Speed control integral gain (Fd-03)
• Position control cut-off frequency (Fd-09)
Note 3
: This function may not show its optimal performance depending on the machine
conditions.
The parameter constants used with this function are described below.
(a) Fast positioning mode (Fd-40)
This parameter specifies how to control the fast positioning. To perform positioning in
the shortest settling time, set this parameter to "FAst" from "non" or "FoL". To perform
positioning while drastically reducing position deviations, use the position deviation
minimizing control by setting this parameter to "FoL". The control operation for each
setting is described below.
• Minimizing the positioning settling time "FAst"
When the fast positioning mode is set to "FAst" from "non" or "FoL", the control
constant parameters are automatically optimized to minimize the positioning
settling time. If the fast positioning mode is already set to "FAst", then set it to "non"
and then back to "FAst" again. Always be sure to first make the other control
parameters (Fd-xx) before setting to "FAst". Making this setting automatically sets
the "Position feed forward gain" (Fd-10) and the "Position feed forward filter time
constant" (Fd-41).
Position overshoot might occur depending on the machine being operated. If that
happens, adjust the "Position feed forward gain" (Fd-10) that was automatically set,
to a new setting where position overshoot does not occur.
• Minimizing the position deviation "FoL"
Setting the fast positioning mode to "FoL" enables the position deviation minimizing
control to work. Position deviation or error which may occur can be adjusted by
the "Position error filter gain" (Fd-42). (See figure below.)