Defining The Scaled Sls4 Limit And Sls4 Trip Limits - ABB FSO-12 User Manual

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Defining the scaled SLS4 limit and SLS4 trip limits

Because the same scaling percentage is used to scale both the original SLS4 limit
and SLS4 trip limit, this affects the difference between new, scaled SLS4 limit and
SLS4 trip limits. The FSO scales the SLS4 trip limit so that the difference between the
new limits does not become too small.
The FSO module first scales the original SLS4 and SLS4 trip limits with the given
percentage. If necessary, the new, scaled SLS4 trip limit is the adjusted according to
these rules:
• If the difference between original SLS4 and SLS4 trip limits < 25 rpm
-> the difference between the scaled limits must be at least the same as the
original difference. See Example 1 below.
• If the difference between original SLS4 and SLS4 trip limits > 25 rpm
-> the difference between the limits must be at least 25 rpm. See Example 2
below.
• The scaled SLS4 trip limit must always be at least the zero speed value
(parameter FSOGEN.51).