User`s guide

Page 101

Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)

6.2.7. Toggling the Preferred Port to Assist Diagnostics

The "preferred port" toggles between PORT1 & PORT2 every time a system diagnostic scan is

performed.

This timing has been shown to be long enough to give good deterministic information about

communicating on any particular port and still be short enough to flag a problem that is developing on

the network.

Also, since the intention behind this toggling is only to help out diagnostics (to flag an actuator when a

port is starting to go bad), the relative time reference here is the time to get a technician to see and

service the actuator & network.

Therefore, the scan period between diagnostic scans is more than fast enough for this (several scaling

magnitudes difference ... seconds for detection as compared to minutes or hours or even days for the

service technician to respond).