EndRun Tempus LX GPS, User Manual

Page: 61 / 116

T e m p u s L X G P S U s e r M a n u a l 48
C H A P T E R S I X
49 T e m p u s L X G P S U s e r M a n u a l
C O N T R O L A N D S T A T U S C O M M A N D S
DAC Control Over-Range: This bit indicates that the electronic frequency control DAC for the
oscillator has reached either the high (55000) or low (10000) limit while locked to the GPS sig-
nal. Unless the unit is being subjected to out-of-specification environmental conditions, this would
indicate that the oscillator frequency has drifted near to the end of life region. This should normally
only occur after about ten years of operation. The unit will continue to function until the oscillator
frequency finally reaches one of the actual DAC endpoints. The unit should be returned to the factory
for oscillator replacement at the customer’s convenience.
No Signal Time-Out:
This bit indicates that the unit has not been able to acquire a GPS signal
for one hour while the Time Figure of Merit has been 9, the unsynchronized condition. This could
be due to a variety of reasons. If there are no other faults that could explain the inability to receive a
signal, then there could be an or antenna failure or blockage. If the condition persists indefinitely, and
a problem with the antenna is not evident, the unit may need to be returned to the factory for repair.
FPGA Config Fault: This bit indicates that the microprocessor was unable to configure the
FPGA. This would be a fatal fault and the unit should be returned to the factory for repair .
FLASH Write Fault: This bit indicates that the microprocessor was unable to verify a write
to the FLASH non-volatile parameter storage area. This should not ever occur under normal opera-
tion. This fault would cause erratic operation at the next power cycling since important parameters
could be corrupt. The unit should be returned to the factory for repair.
GPS Comm Fault: This bit indicates that the microprocessor is unable to establish commu-
nications with the GPS engine. Please report this fault condition to the factory (1-877-749-3878).
Time Input Fault: This bit indicates that the microprocessor received an erroneous time
input from the GPS engine. If the condition persists please report it to the factory (1-877-749-3878).
No Polling Events: This bit indicates that the GPS timing subsystem is not receiving poll-
ing request from the NTP subsystem. This could be due to a hardware or software failure. If the con-
dition persists after cycling the power to the unit, this is a fatal fault and the unit should be returned to
the factory for repair.
Antenna Fault: This bit indicates that the GPS antenna or downlead cable has a fault.
It indicates either an over or under current condition. Usually it means that the antenna downlead
cable is not plugged into the connector on the rear of the Tempus LX. If the condition persists after
checking the antenna/downlead for obvious faults, this is a fatal fault and the unit should be returned
to the factory for repair.
The example response indicates that there has been a period without tracking a GPS signal that ex-
ceeded the time-out period, that there was a FLASH Write Fault and that there is an Antenna Fault.
Query:
gpsstat
Tempus LX response:
LOCKED TFOM = 4 2001 092 04:48:56.347916732 13 13 2 7 28605 41.6 008A
gpstrkstat
This command displays the current GPS subsystem satellite tracking status. A list of eight satellite
numbers is displayed, one for each receiver channel. Satellite number 0 is an invalid number and
indicates that no satellite is being tracked on that channel. Valid satellite numbers range from 1 to 32.