Grass Valley 8972PX - Manual (Page 26)

26 8972PX — Instruction Manual
Configuration Summary
Passive Bypass Only Mode
The Passive Bypass Only mode has two main purposes as described below:
1. During normal operation, the Bypass mode for the module is set for
Active Processing Enabled on the System Config web page. The module can
be set for Passive Bypass Only to simulate the relay-protected bypass state
that occurs when power is lost or the front module is removed. The
Passive Bypass Only mode is normally used for maintenance purposes
such as cabling or testing the rear module relay bypass path.
When set for Passive Bypass Only , the module simulates the bypass state
where the Primary and Secondary inputs are switched by relays on the
rear module to the Relay-Protected Program Output at BNC, J7 as
shown in
Figure 5 on page 27 . The Primary and Secondary input
signals now bypass the front module completely and the Status of the
Primary and Secondary inputs on all web page headers are reported as
Bypassed as shown in the example in ( Figure 22 on page 56 ). As this
mode is only a simulation of removing the front module, putting the
module in this mode does not affect the other controls on the front
module or the Alternate input.
In this mode, output J7 (Relay-Protected Program Output), remains the
input previously selected (except if it was the Alternate input it will be
switched to the Primary input). When the module is switched back to
Active Processing Enabled on the System Config web page, it returns in
Manual mode with no change to the Program Output.
2. When power is lost to the frame or the front module is completely
removed, the relay-protected Primary and Secondary inputs will
automatically be switched to the rear module relay bypass path and the
input previously selected will be latched to the output at BNC J7, the
Relay-Protected Program Output. The passive bypass path ensures the
continuous transmission of the Primary/Secondary input signal to the
Relay-Protected Program Output. When power is returned to the frame
or the module is reinserted, the module will be in Manual mode with
no change to the Program Output.