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IOTA-VTI Operation Manual
The Time Screen – Error Messages :-
IOTA will display on-screen an error message to alert the user that an event occurred
that may affect the time displayed. The message will appear within one second of the event
occurring and will advise of the error type and time of the error event.
The philosophy of IOTA-VTI error reporting is to squawk loudly on error, meaning the
user is advised within one second of an event that may effect the quality of the timestamp.
The error type and the time of the event are reported at the top of the Time screen
and displays 1 error per line. The meaning of the error is as follows.
Error Name
1
UTnotSeq
2
NoPPS
3
NoGPSmsg
4
LoopTooLong The main loop took too long to write the Time message properly on
6
PPStooQuick may occur while the unit is re-stabilising after a Loss Of Signal.
7
NoGGA
8
twoGGA
9
antAdvis
These errors usually represent problems in communication between the GPS unit
and the microcontroller or are induced by an electrically noisy environment.
Note: Error 5 is retired.
Error messages may be set as Persistent or Transient via the setting of the DIP switch.
-
Transient means that error messages remain on screen for 5 seconds then are
automatically erased when timing returns.
-
Persistent means the error message remains on-screen until cleared by the
operator, by changing to the position screen and back, or by reset.
Time Screen - Almanac Updates:-
If the backup battery supply to the GPS fails or the battery was tampered with during
the shut down period the GPS's almanac will revert to the default status. The offset between
GPS-time and universal time may be incorrect depending on whether leap seconds have
been added after the GPS manufacture date.
This condition is reported on the Time screen by the presence of the Hour Glass.
- 7 -
A 1PPS was detected, as well ad GGA information that described
it, but the description was not what was expected.
A One Pulse Per Second (1PPS) was not received.
No useful NMEA Sentence was received
screen. This is set at 15 msec (PAL) and 12.5msec (NTSC).
GGA sentence was delayed. This error will shut down the UT
display for five seconds until the unit has recovered. If it occurs
frequently, reposition the antenna away from sources of RFI.
Two GGA sentences were received. This will occur in tandem
with and just after a NoGGA error.
The unit received an unexpected antenna advisory message while
in Time mode
Details
Video Timers
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