User's Manual

WEMS Installer’s Guide 24
WEMS Software
Uplink Scheduling Menu
The WEMS devices run autonomously according to the uplink schedule set in the
uplink scheduling menu. Sensors uplink to an iCCU, and an iCCU uplinks to a
computer via satellite. To access this menu, select the Sched tab as shown in
Figure 16 below. The software allows for four time schedules. For each time
schedule, the software allows three pull-down options - Enabled, Disabled, or
Hourly. In the Enabled mode, the device uplinks once daily at the time specified.
In the Hourly mode, the device uplinks every hour at the minute/second
specified. Normally, Hourly mode is only used for testing purposes. To change
the time, click on the desired field, (hour, minute, second, AM/PM), and use the
up/down arrows to change the field. Once the desired schedules and times are
entered, hit Set Uplink Times to accept the changes.
Sensor devices must uplink to an iCCU at specific time intervals when the iCCU
accepts data uplinks. The iCCU is active for one minute every ten minutes
“on the tens” of every hour. In other words, the iCCU is active from
00 min. 00 sec. after the hour to 01 min. 00 sec. after the hour; from
10 min. 00 sec. after the hour to 11 min. 00 sec. after the hour; from
20 min. 00 sec. after the hour to 21 min. 00 sec. after the hour; etc. Therefore,
synchronizing the real-time clocks on all devices and properly scheduling the
uplink times on sensor devices are very important.
When setting the uplink time on a sensor device, keep in mind that, over time,
the real-time clock may drift out of synchronization by a few seconds.
Therefore, do not select an uplink time that is too close to the beginning or end
of the uplink time window. Choose a value for the seconds field that falls
between 15 and 45 seconds as in the example in Figure 16. Also, if the iCCU is
linked to several sensor devices, space the uplink times for each device about
five seconds apart to keep two devices from uplinking at the same time.