Comtech EF Data RCU101 - Manual (Page 19)

RCU101 1:1 Protection Switch Operation
TM055 - Rev. 2.2 Page 3-1
Section 3 - Operation
3.0 Definitions
The nomenclature used throughout this manual is meant to imply various roles that each (up or down)
converter assumes depending upon the state of the converters and the settings of the protected
converter system. These descriptions are as follows:
A Protected Converter System consists of the primary converter, backup converter, and the RCU101
switch and required interface cables.
The Primary Converter is the converter that is connected to the Primary Port on the Switch.
The Backup Converter is the converter that is connected to the Backup Port on the Switch
The Online Converter can be either the primary or backup converter.
3.1 Operation
The 1:1 protection switch unit provides automatic restoration for one online converter. An RS485
equipment interface allows the backup converter to ‘learn’ the frequency and gain settings of the
primary converter. The learning process is initiated by the user, via the backup converter. By entering
the Utilities menu from the front panel of the backup converter, it will allow the user to initiate the
learning process. The backup converter will indicate whether the learning process was successful. If
the process was not successful, the converter will indicate the learning process failed. Refer to the
converter manual for more details.
(MENU) for next menu
(ENTER) for Learn Mode
Automatic Learning in Process Automatic Learning
Failed
Automatic Learning
Successfully Completed Reason For
Failure
3.1 Switch Logic
The RCU101 uses the output of the Form-C relay in the converter to determine what action to take. In
the following descriptions, it is assumed that the switch is in Auto mode and that the other converter is
not faulted. (If the switch were in Manual mode, no switching would take place).
The Fault N.O logic level is derived from the normally open contact of the summary fault Form-C relay
in the converter. The converter, when clear of any and all faults, asserts the summary fault relay to the
not faulted state and the contact is open. A fault in the converter, turning the converter off, failure of
the converter power supply, or disconnecting the switch interface cable will cause the relay to close.
Upon detection of this event, the switch will toggle control and data to the other converter.
Once the fault in the faulted converter is cleared, the converter will reset the summary fault relay and
the contact will again be open. Upon detection of this event, the switch will place the converter in
standby, so that it can be placed online in the event that the other converter fails. The switch will not
automatically switch back to the original online converter.
The following truth table illustrates this switching logic. A ‘1’ in this table indicates that the
corresponding converter is faulted.