Network Planning and Diagnostics
Network Commissioning
66
SKF Wireless Machine Condition Sensor
Service Manual
Network Commissioning
The recommendations below support successful network commissioning.
•
Always start up a gateway before turning on the sensors. If you do not, the sensor
will turn itself off within an hour of not finding the gateway and it will not try to
reconnect until the next day.
A sensor will wake up to look for a network to join
every 24 hours after it has searched for an hour and failed to connect.
Do not use the Network ID 1229 unless it is a commissioning
network. The sensor will attempt to join for
one hour then shut
down completely if the network is not found. It will remain off
until manually re-activated by the push button.
•
If there is commissioning network on site, make sure it is out of the signal range of
the production network.
•
Test the sensors within the 1-hop distance to the production gateway before
deployment to verify the network settings are correct.
•
Start up the sensors closest to the gateway first, that is the 1-hop sensors, and
then move out in sequence to the sensors farther away from the gateway. Start up
all 2-hop sensors, then all 3-hop sensors. While building the network, switch on
Activate Global Advertising
in the
gateway’s
Setup
web page) and all field devices to shorten the time required for
new sensors to join the network.
•
The number of sensors
joining simultaneously affects network formation tim
e
because these sensors
must compete for limited join links and downstream
bandwidth. So when too many sensors sync up at once they will contend for the
same shared access point links which can slow down the overall network formation
time.
Network Diagnostics
Key Considerations
Is the network formation time acceptable? The formation time should be less than one
hour because sensors that have not joined by then will automatically turn off.
Reliability
- Verify the reliability is close to 100%. This is the percentage of unique
packets received relative to the number generated. (See the example in Network
Reliability
is indicated in blue.)
All network statistics require at least 15 minutes after the last
mote has joined
to develop.
Stability
– The ratio of acknowledged packets to packets sent between two nodes;
nodes are also known as motes. This step involves looking at all the discovered paths in
the network, and making sure that every mote has enough good quality neighbors. The
bare minimum is that every mote should have at least three good neighbors. A good
neighbor is a neighbor that this mote can hear at greater than -75 dB with better than