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User Manual
Chapter 4
GFK-1742F
Jan 2020
Configuration
127
6.06 Velocity at MaxCmd (User Units/Second.) All DSM314 analog servo functions
depend on this value being correct for proper operation.
For Digital Servo Mode, the Velocity at Max Cmd configuration field is not used.
For Analog Servo Mode in Velocity Mode, the Velocity at Max Cmd configuration
field is the Actual Servo Velocity (User Units/second) desired for a 10 Volt DSM314
analog velocity command output to the servo. The Force D/A Output %AQ
Immediate Command and the Actual Velocity %AI status word can be used for a
command voltage to empirically determine the proper configuration value if
necessary.
For Analog Servo Mode in Torque Mode, the Velocity at Max Cmd configuration field
is the maximum velocity that the user desires the servo to be able to run. The value
is determined by the capabilities of the servo system being controlled and the
capabilities of the driven load.
In Digital Mode only, if the user sends the DSM314 a velocity command that exceeds
the servo system capability, the DSM314 will clamp that command value at the
appropriate maximum motor velocity boundary. Note that no error will be reported
back to the DSM314.
See Appendix D, “Start
-
up and Tuning Digital and Analog Servo Systems,” for more
information on determining the correct value.
Default: 100000.
CAUTION
The Velocity at 10V must be configured correctly in order for the analog servo Pos
Loop Time Constant and Velocity Feedforward factors to be accurate.
6.07 Velocity Feed Forward (0.01%). Velocity Feed forward gain (units = 0.01 percent).
The Commanded Velocity percentage that is added to the DSM314’s position loop
velocity command output. Increasing Velocity Feedforward causes the servo to
operate with faster response and reduced position error. The optimum value for
each system has to be determined individually. For Digital Servos, 95 % Velocity Feed
Forward Percentage value is a good starting point. For analog servos, 70% is a good
starting point. The servo system capabilities will determine the optimum value. If
Velocity Feed Forward is changed, Pos Err Limit may require adjustment. Default: 0.
CAUTION
For Analog Axes, the Velocity Feed Forward Percentage will not be accurate unless
the Velocity at MaxCmd value is first set correctly.