Basler Electric DECS-250N - Manual (Page 48)

32 9440500990 Rev D
Regulation DECS-250N
The following examples demonstrate the advantages of internal tracking:
•
If the excitation system is operating online with internal tracking enabled, a loss of sensing condition
could trigger a transfer to FCR mode. Autotracking minimizes the impact that a loss of sensing
condition has on the exciter’s ability to maintain the proper excitation level.
•
While performing routine testing of the DECS-250N in backup mode, the internal tracking feature
allows a transfer to an inactive mode that will result in no disturbance to the system.
Two parameters control the behavior of internal tracking. A delay setting B determines the time delay
between large system disturbance and the start of setpoint tracking. A traverse rate setting C configures
the length of time for the inactive mode setpoints to traverse the full setting range of the active mode
setpoint.
External Setpoint Tracking
For critical applications, a second DECS-250N can provide backup excitation control. The DECS-250N
allows for excitation redundancy by providing external tracking and transfer provisions between
DECS-250N controllers. The secondary DECS-250N can be configured to track the primary DECS-250N
setpoint. Proper redundant excitation system design allows for removal of the failed system.
Note
Periodic testing of the backup system must be performed to ensure
that it is operational and can be placed in service without warning.
Like internal tracking, external setpoint tracking uses enable/disable D , delay E , and traverse rate F settings.
Figure 20. Autotracking Settings
A Internal Tracking Enabled: Place a check in the checkbox to enable internal tracking.
B Internal Tracking Delay: Adjustable from 0 to 8 seconds in 0.1 second increments.
C Internal Tracking Traverse Rate: Adjustable from 1 to 80 seconds in 0.1 second increments.
D External Tracking Enabled: Place a check in the checkbox to enable external tracking.
E External Tracking Delay: Adjustable from 0 to 8 seconds in 0.1 second increments.
F External Tracking Traverse Rate: Adjustable from 1 to 80 seconds in 0.1 second increments.
Setpoint Configure
When the Auto Save setting is enabled, the DECS-250N automatically saves the active setpoint in one-
minute intervals. Otherwise, the setpoint which was last sent to the DECS-250N is retained. Figure 21
illustrates the Setpoint Configure screen.
Figure 21. Setpoint Configure Setting