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GPS
It is possible to use a GPS to provide the MONITOR with an accurate, self setting clock.
MONITOR can be connected to a Garmin GPS 16HVS.
Timekeeping
When equipped with a GPS, the MONITOR will keep UTC time. UTC (Universal
Coordinated Time) is an internationally accept time standard. UTC will differ from the
local time by a number of hours. The user can
setup the MONITOR so that it keeps local
time by changing the variable Local Time Offset. To get EST, set the local time offset to
-5 hours.
A MONITOR equipped with a GPS will provide a timing accuracy of ± 1 second.
If you are using a GPS, a MONITOR, and a Sutron SDI-12 device such as the SDR,
RLR, or CF Bubbler, you may connect the GPS to the SDI-12 device rather than to
MONITOR. The correct time will then be used by the sensors and by MONITOR. This
way you will free up the RS232 port on MONITOR for another device (such as a
modem). For details on SDI-12 time sync, please see the section
SDI Clock
Synchronization
.
GPS Installation and Setup
When first installing the GPS, make sure the GPS is positioned so that it has a clear view
of the sky. Make sure to connect the GPS to the MONITOR via RS232. Sutron provides
a custom RJ45 to RS232 connector for this purpose (the diagram for the connector is on
page 66).
After connecting the two devices, go the
Station Setup
menu on the front panel
of the
MONITOR. Find the entry called
Garmin GPS
and press set to enable the GPS. Then go
back to the top of the menu, and hit the down button until the
GPS status menu
is
shown. If the MONITOR is communicating with the GPS, the menu will say
GPS initializing
. If the GPS has acquired a time fix, the MONITOR will show
GPS
functioning
.
Pressing right in the GPS status menu will provide more details.
If the GPS has locked on satellites and is providing accurate time, the menu will show a
message such as
GPS has valid time
5 satellites used in time fix
Pressing down from the detailed status menu will show the
last GPS time sync
. The
time show is the time when the GPS last had a time fix. If it has been more than 12 hours
since the last valid time fix, the GPS is not working properly and may need to be
repositioned (please see page 65).
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