Publication 2098-IN005C-EN-P — March 2008
Minimizing the Effects of Feedback Signal Loss 149
Understanding Error Limit Settings in Ultraware Software
With the motion application configured and operational, observe the
default Following Error and Velocity Error Fault limit settings in
Ultraware software to understand the significance of their values and
units.
Ultraware Faults Branch
The Following Error Limit setting is in units of interpolated counts and
can be related to actual position error in units of raw feedback counts
and axis revolutions by referring to the motor and encoder properties
found in the Motor and Encoders branches of Ultraware software.
In this example, the motor encoder provides 1024 raw counts per
motor axis revolution with an interpolation constant of 1024. This
creates a total of 1048576 interpolated counts per motor axis
revolution. Therefore, the default 8000 interpolated-count
position-error limit setting allows for maximum position error of 0.76%
of a full motor axis revolution before the condition of Excess Position
Error (E19) is reached.
The Velocity Error Fault Limit setting is in units of percent of
maximum motor speed and can be related to actual velocity by
referring to the motor properties under the Motor branch. In this
example, the motor is rated for a maximum speed of 5000 rpm.
Therefore, the default 25% setting allows for as much as 1250 rpm of
velocity error before the condition of Excess Velocity Error (E24) is
reached.
Optimal Following Error Limit/Time and Velocity Error Fault Limit/
Time settings are chosen based on your knowledge of the system
requirements and the maximum system position and velocity error
excursion limit values. The default limit settings may not be optimal
for every application. You must understand the application needs and
adjust these default limit settings as appropriate.
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