15
GPS Network Time Server
TECHNICAL: 0118 965 6000
The power on sequence of the two-colour LOCKED and POWER indicator is intended to
check the clock start-up, while checking the correct operation of the indicator lights:
LOCKED
POWER Comments
Standard hardware
resource self-testing
Red
Red
Checks the clock operation
Optional hardware self-
testing
Green
Red
Checks the options
Synchronization period
Red
Green
Search for signals transmitted by the
GPS satellites
In the event of a hardware fault, the Alarm output (connector J1) is activated (relay contact
closed) and the POWER indicator goes red.
The conditions for activation of this output are the following:
•
GPS receiver fault;
•
Frequency pilot fault;
•
Frequency division circuit fault;
•
Fault in the distribution of the frequency or synchronization signals;
•
Synchronization or frequency performance fault*
*this function is programmable via the remote control interface.
If the fault occurs during the start-up sequence, both "LOCKED" and "POWER" indicator go
red. Under such condition, the time message is no longer distributed (Time Of Day message,
connector J3) and the clock no longer synchronizes with the GPS source. In such a case,
contact the Black Box technical support.
When all indicators are out, the clock is not powered.
When the "LOCKED" indicator goes green, the front panel illuminates. When this indicator
goes red to indicate the start of synchronization period, the front panel display indicates the
initial date, time, and increments on each second. This time indication starts at the end of the
self-tests at: 01/01/92 00:00:00N
.
The system then automatically switches over to UTC time acquisition.
Note: The "POWER" indicator goes red at the end of the self-test and remains red throughout
the heating time of the internal oscillator, this will be a maximum of 20 minutes.
The "LOCKED" indicator remains red until UTC time acquisition by the GPS receiver.
Acquisition lasts less than 30 minutes when the GPS constellation is under nominal operating
condition.
