Comtech EF Data KPA - Manual (Page 87)

B–1
Appendix B. KPA REDUNDANT
OPERATIONS
B.1 Introduction
IMPORTANT
Comtech EF Data’s KPA family of ISSPAs are designed to automatically
sense and configure into Redundancy Mode when the redundant loop cable
is connected. Polling on the dedicated redundancy bus will not begin until
the redundancy loop cable is connected. Each KPA’s designation in a
redundant subsystem is determined automatically via the redundancy
interface cable connected between the two (i.e., 1:1) or three (i.e., 1:2) KPAs
in the redundant configuration.
All Comtech EF Data KPAs are designed to operate in both standalone and redundant
configurations. Every KPA contains the circuitry and logic necessary to perform all the functions
of a backup controller in both a 1:1 and 1:2 configuration. This includes the ability to monitor and
control up to two RF waveguide switch assemblies. As note previously, the KPA has additionally
been designed to automatically detect whether it is in a standalone or redundancy system. These
features greatly simplify redundancy configurations from both the cost and operational
complexity standpoint.
In a redundant configuration, the backup KPA in the redundancy subsystem automatically monitors
the configuration and status for each of the primary (chained) KPAs. This information is
communicated via the dedicated serial interface between the KPAs.
If a primary KPA fails, the backup detects this event and automatically reconfigures itself to the
proper attenuation setting and positions the waveguide switch to provide minimal loss of traffic.
A result of this design is to greatly lessen the throughput requirements (i.e. polling rate) of earth
station monitor and control systems. The backup KPA handles all of the time-critical tasks,
allowing the earth station monitor and control system to focus on less intelligent subsystems.