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16
Chapter 2
Technical Description
2.4.2 Standard Receiver Alarm Outputs
Alarm inputs are managed by the receiver as follows:
The 20 committed digital alarm points are connected to individual LEDs on
the front of the unit. All 27 digital alarm points (committed and
uncommitted) are connected to the SUM LED.
All 27 digital outputs are provided with opto-couplers. There are two
connectors in the rear of the receiver containing connections from all of
the opto-coupler outputs.
Each of the four analog telemetry channels have eight data bits which are
latched and fed to the corresponding D/A to provide voltage readings. The
four voltage readings update every 12 seconds.
Battery voltages and the uncommitted voltage are brought to the face
plate via test points. The voltage level readings are calibrated from 0.0 V
to 10.0 V and should be multiplied by 3 for the actual voltage level.
The battery temperature is given in voltage. Use the Temperature
Conversion Table to convert the voltage to degrees in Celsius
—
see
Section 3.3.6
, Battery Temperature Transducer
, page 29.
The analog voltage readings (positive respect to GND) can be brought to
the user interface connector.
2.4.3 Sync Loss Alarm
If for any reason the microwave path fails (Repeater failure, terminal radio failure,
excessive fade, etc.), the SYNC LOSS LED flashes and the alarm status at the
receiver freezes to the last reported condition. If this occurs, determine the cause
of the failure and clear the display by pressing the RESET button on the receiver
front panel.
The SYNC LOSS status can be wired to standard supervisory equipment with
opto-coupler contacts. Supervisory personnel can remotely monitor when alarm
data is not current and inspect the Repeater and the RMAS-120 to detect the
cause of synchronization loss.