Comtech EF Data MBT-4000B - Manual (Page 31)

Multi-Band Transceiver System Revision 0
Redundant Configuration MN/MBT4000B.IOM
4-3
For a switchover to occur:
• Both MBT-4000B base units must be set to redundancy mode 2, the RED=2 command
must have been received by each base.
• Both chains must be set to automatic mode. For example, if the redundant pair is on
Slot 2 of the bases, the command RAM=21 must have been received by each base.
• The corresponding standby chain must not be in faulted state.
4.3 External Fault Monitoring
Each MBT-4000B base includes a logic input, on the AUX COMM connector, that may be
connected to contact closure fault indications of external equipment (usually an SSPA or TWTA).
Thus, external equipment failure may participate in overall fault indication and redundant
switchover operation according to the following rules:
Step Procedures
1 An open connection (or 2.7 V min) indicates a fault condition exists.
2 A closed connection (or 0.7 V max) indicates no fault condition exists.
3 Maximum voltage range on fault logic inputs is –12V to +12V.
4 The fault input of AUX COM 1 corresponds to the BUC installed as UNIT 1.
5 To enable fault input checking the EAM=1m command is used.The mode parameter ‘m’ can
equal 0 for disabled, or 1 for enabled
4.4 LNB Power Supply Current Monitoring
The bias tee in the MBT-4000B base is used to supply power and the 10 MHz reference to the
LNB.
This power supply features current monitoring with programmable failure limits. Over-current
and under-current failures can participate in overall fault indication and redundant switchover
criteria.