Echelon LonScanner FX Protocol Analyzer - Manual (Page 63)

LonScanner FX Protocol Analyzer User’s Guide 57
Figure 45. Example Log File Two – Packet 24 Selected
At packet number 22, device DI-1 is sending out an acknowledged network
variable update message to device AO-1, but device AO-1 fails to respond.
Packets 23 through 25 are retry messages (see Figure 45). The alternate
path attribute is set on the last two attempts, packet number 24 and 25, of
an acknowledged transaction. This concept also applies to a
request/response transaction. If a host monitoring application fails to get
an update, check the log file to verify whether the target device fails to
respond to a network variable fetch message.