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Appendix M. PakBus Networking Details

Beacon Interval: 60 seconds

Verify Interval: 150 seconds

Hello List: None

Central Router: None

M.8 Optimization

Since response speed is always important, you should use the fastest IO

mode available. Specifically the fastest IO mode is CSDC for the

datalogger interface and 38.4k for the RS-232 interface. Another

reason to use the fastest IO mode is that the RF401 buffers the entire

PakBus packet before sending it to the radio module (the RF400 would

just start streaming it to the radio immediately), and therefore introduces

a delay.

The RF401 or RF430 can handle full size (1000 byte) PakBus packets.

However, decreasing the size of the PakBus packets to ~240 bytes will

provide better throughput when there is heavy RF traffic or the

collection of a lot of data. Large PakBus packets are spread across

multiple RF packets, which could cause another RF packet to be

interleaved, leading to the corruption of the larger PakBus packet.

Essentially, the PakBus packet is fragmented, and received out of order.

No mechanism exists that reorders the individual RF packets. The

PakBus size is an adjustable setting in our PakBus dataloggers and in

the LoggerNet server.

M.9 Idiosyncrasies

As mentioned under Net and Radio Address Settings, only four Net

Addresses are available (0-3). Combining the seven unique hop

sequences with the four Net Addresses provides a total of 28 (4x7)

unique combinations for networks. This is far fewer combinations than

available for the RF400 radios, increasing the likelihood of RF401

networks that merge unexpectedly.

Also, there is potential for interference from RF400 radios. RF400

radios with Net Addresses of 28, 44, 52, and 56 will interfere with and

be interfered by RF401 or RF430 radios with Net Addresses of 0, 1, 2,

and 3 respectively. The RF400 Net Address of 60 will interfere with

ALL RF401 Net Addresses. Therefore if RF400 radios and

RF401/RF430 radios will be in the same RF proximity, do not use 28,

44, 52, 56, or 60 for the RF400s Net Addresses.

A positive side effect of the RF PakBus protocol is that the node that is

attached to the RF401/RF430 (datalogger or server) will only receive

PakBus packets that are addressed to it or globally addressed packets.

The rest of the packets are filtered out by the radio. This will reduce the

overall current consumption of the datalogger.

When the Protocol is set to one of the PakBus protocols, the radio

“discovers” the PakBus address of the attached node by looking at the

header of any outbound PakBus packet. If no outbound packet (could

be a beacon, or Hello, or anything else) is sent for 6 minutes, the RF401

will send a Hello Request packet to the attached node. If the protocol is

set to PakBus Aware, these Hello Request packets are sent alternately

M-4

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