Comtech EF Data RRS11 - Manual (Page 21)

RRS11 Solid-State Transfer Switch Operation
MN-RRS11 3–3
Rev. 3
3.2 Operating Procedures
The Solid-State Transfer Switch is designed for minimal operator intervention and control during
normal operation. After initial setup, the unit should operate in a relatively ‘transparent’ manner,
providing trouble-free backup of the online modulators
3.3 Solid-State Transfer Switch Backup Operation
The RRS11 Switch monitors the fault status from each modulator. Each DM240-PIIC or
DM240XR supplies DC voltage and fault status to the RRS11. An additional DB9 connector has
been added to the rear panel of the DM240-PIIC or DM240XR that provides a wiring port to the
external switch. Each modulator is capable of powering the switch through a current limited,
diode or’ed power signal. Either of the DM240s is also capable of commanding the switch to the
prime or backup state, as well as monitoring in which state it is. Additional menus are available
on the DM240 front panel menus or remote port that allow user to control switching parameters.
In normal operation, the M&C in the backup modulator monitors the prime for faults. If one is
detected, it will automatically cause the switch to place the backup on-line. The switch is non-
revertive. That is, once a switch occurs, it requires a manual command (either through the M&C
or from the front panel) to return the prime unit to an on-line status. This will be the default
operation, but the switching software is capable of implementing revertive switching as well.
Either modulator will be capable of changing the state of the switch (assuming it is not faulted).
This can be done remotely or from the front panel. Remote control will occur through the
standard Ethernet M&C interface implementing SNMP. The switch connectors are listed in
Table 3-1 and 3-1A.
Table 3-1, RRS11 70/140MHz Rear Panel Connectors
Connector
ID
Nomenclature Description
J1 Online Status
Output
9-Pin D-Sub Switch Status Form-C Relay Outputs
J2 Prime Mod Control 9-Pin D-Sub Control Connector From Prime Modulator
J3 Backup Mod Control 9-Pin D-Sub Control Connector From Backup Modulator
J4 Monitor A Input SMA (f) 50 Ohm from Modulator A Monitor Output
J5 Monitor B Input SMA (f) 50 Ohm from Modulator B Monitor Output
J6 On-Line Output BNC (f) 75 Ohm, Output of On-Line Modulator to Uplink Chain.
J7 Off-Line Output BNC (f) 75 Ohm Output of Monitor Port of Off-Line
Modulator
J8 70/140 IF Input A BNC (f) 75 Ohm From Modulator A
J9 70/140 IF Input B BNC (f) 75 Ohm From Modulator B