Grass Valley Trinix NXT v.3.3.1 - Manual (Page 95)

Trinix NXT — Installation and Service Manual 95
Protected Paths
Protected Paths
Overview
The Protected path function is designed to monitor router outputs that are
feeding critical downstream equipment and, in the event of signal loss, will
automatically select the output that is carrying the same signal and trigger
the system alarm.
The Protected path function assumes the following:
• Supported Output Boards provide the output signals that will be mon-
itored. These boards allow individual outputs to be enabled or disabled
using software controls.
• Protection is provided for paths, that is, input/output pairs. The installer
must identify critical outputs and an associated critical input for each.
For redundancy, two paths must be defined: a Primary path and a
failover Secondary path.
• Protected pairs should be hard wired to back-panel connectors that will
provide the most independent possible paths through the router. For
example, the two paths should use different input boards and different
output boards. Depending on router size, the two paths may also be
able to use different matrix boards and different power sources.
• Two copies of each protected input must be wired to the router for full
redundancy. For example, the Master Control switcher output could be
sent through a passive splitter upstream of the router. One copy is used
for the primary path, and the other for the secondary path. If an
upstream splitter is used, steps must be taken to boost the gain for the
appropriate block of inputs.
• The primary output and the secondary output must be wired to a
passive combiner; the output of the passive combiner is then connected
to the downstream equipment. The Protected path software will auto-
matically boost individual outputs as needed for proper gain level
through the splitter. Outputs not configured for Protected path opera-
tion should be set for gain levels as described in the manual. (The Pro-
tected path software will override the manual settings as needed.)
• The control system (for example, Encore or Jupiter) must be operated
so that the secondary path is always ready to provide a copy of the pro-
tected signal. For example, the operator would switch the Master
Control output to the transmitter on the primary path; the control
system would then switch the secondary path automatically. For more
information, see Jupiter Facility Control System
on page 106 .
Figure 54 on page 96 shows an example of a TRX-NXT-512x512 router with
a pair of Protected paths (Depending on system requirements, the
upstream splitter may or may not be needed). The signal detector monitors