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Figure 2: Iridium Properties Dialog
Enabled
The Enabled checkbox determines whether Xpert will do any kind of Iridium processing. The
checkbox must be checked for Xpert to initiate self-timed and alarm transmissions, process
incoming commands over Iridium, etc. If Enabled is not checked, the Xpert behaves as if the
modem is not connected, and will not process any incoming or outgoing transmissions.
Comm Port
Select the Xpert Comm Port to which the Iridium modem is connected.
Sync Time
When the Sync Time checkbox is checked and recording is ON, the Xpert will set its system
time to Iridium system time (which follows GMT). This time synchronization will only occur
during a transmission or message check, and will only occur up to once daily.
The Iridium system provides GMT time using a counter relative to an “epoch” time defined by
the Iridium authority. The epoch time changes roughly every 7 or so years. In order for the Xpert
to compute system time properly through a change to the Iridium epoch, the Xpert must store
both the current epoch time, and the next expected epoch time. As of version 3.15, the Xpert is
programmed to handle an Iridium epoch change in May, 2014.
Iridium will announce new epoch changes in coming years. When a new epoch date is
announced, the Xpert must be told to store the new date. To change the value of the next epoch
date-time stored in the Xpert, send the following command to the Xpert via Iridium short burst
message:
!irsenxt MM/DD/YYYY HH:MM:SS
For example, to set the next epoch date-time to 5PM June 3, 2020, you would send, “!irsenxt
06/03/2020 17:00:00”.
It’s also possible to set the
current
Iridium epoch date-time in the Xpert, though this would only
be required if the Xpert failed to set the proper epoch date itself during an epoch transition. To
set the current epoch date, you would send the command, “!irse MM/DD/YYYY HH:MM:SS”.
