SA Bus traffic includes change of value (COV) messages that are issued from inputs
and commands issued to outputs located
. Excessive traffic is defined as more
than 500 COVs per minute or more than 500 commands per minute.
To resolve communication issues associated with excessive SA Bus traffic, reduce the
number of COVs to fewer than 500 per minute and the number of commands to fewer than 500
Note: The limit of 500 commands per minute is an approximate maximum that assumes a 1
second token loop time. If your network is configured differently, the actual
threshold for this problem may vary. For example, if your token loop time is 2
seconds, the maximum is 240. If you reduce traffic on the SA Bus to 500 and still
experience this problem, or you are uncertain of your token loop time, we recommend
you reduce command traffic to 240.
To find the number of COVs and commands on your SA Bus, see Inputs and COVs and Outputs and Commands. For strategies on
reducing traffic on your SA Bus, see SA Bus Traffic Reduction.