Specifications

Section 14. PakBus Overview
14-5
Hence, the size of the responses to the file receive commands that the CR1000
sends will be governed by the maxPacketSize setting for the datalogger as well
as that of any of its parents in LoggerNet's network map. Note that this
calculation also takes into account the error rate for devices in the link.
BMP5 data collection transaction does not provide any way for the client to
specify a cap on the size of the response message. This is the main reason why
the "Max Packet Size" setting exists in the CR1000. The CR1000 can look at
this setting at the point where it is forming a response message and cut short
the amount of data that it would normally send if the setting limits the message
size.
14.5.2 Ping
Link integrity can be verified with the following procedure by using
PakBusGraph | Ping Node. Nodes can be pinged with packets of 50, 100, 200
or 500 bytes.
Do not use packet sizes greater than 90 when pinging with
RF400-series radios or CR200-series dataloggers.
Pinging with ten repetitions of each packet size will characterize the link.
Before pinging, all other network traffic (scheduled data collections, clock
checks, etc.) should be temporarily disabled. Begin by pinging the first layer
of links (neighbors) from the PC, then proceed to nodes that are more than one
hop away. TABLE 14.5-1 provides a link performance gage.
TABLE 14
.5-1. PakBus Link Performance Gage
500 byte
Ping Sent Successes Link Status
10 10 excellent
10 9 good
10 7-8 adequate
10 <7 marginal
14.5.3 Traffic Flow
Keep beacon intervals as long as possible with higher traffic (large numbers of
nodes and / or frequent data collection). Long beacon intervals minimize
collisions with other packets and resulting retries. The minimum
recommended beacon interval is 60 seconds. If communications traffic is high,
consider setting beacon intervals of several minutes. If data throughput needs
are great, maximize data bandwidth by creating some branch routers, and / or
by eliminating beacons altogether and setting up neighbor filters.
NOTE