4.15 Wireless Device Sync Setting
All “Interval Type” wireless devices contain configuration
CFG_INT_TYPE_SYNC @ offset 45 that enables them to
synchronize data reporting to an external clock. Value can
range from 0 – 5. If the value is 0 [default], the wireless
devices do not synchronize report interval and will report
data in respect to its startup time. If the value is 1 – 5, the
wireless device attempts to track its report time based on
the Serial Modus Gateway’s time. It is important that
GWTIME in the Gateway Registers is set with an
appropriate time reference. For instance, GWTIME could
be set to the number of seconds from January 1st, 2010,
00:00:00. Now when the Sync setting is not set to 0, the
wireless device will constantly adjust its reporting interval
to closely track a modulus of the gateway’s time. As an
example, if a wireless temperature sensor has a report
interval of 30 minutes and this sync setting is enabled, this
sensor will report its data near to 00:00, 00:30, 1:00, 1:30,
…, etc.
The difference in the enabled values of 1 – 5 correlate to
the number of “random seconds” that is included in the
calculation of next report interval. Theses setting are
useful in managing networks of different sizes. If 20
sensors were all configured to synchronize and deliver
data at the exact same time, the RF collisions would
cripple the sensor network. Please see table below for
recommend settings to be used with specific network
sizes.
Sync Setting
# of Devices
Random Time
1
1-2
1 Second
2
3-7
3 Seconds
3
8-15
7 Seconds
4
16-25
15 Seconds
5
26-50
30 Seconds
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