Knowledge Base
cancel
Showing results for 
Search instead for 
Did you mean: 

It is normal for a BACnet network port's Poll Service 'Busy Time' property to be greater than 100%?

Issue

It is normal for a BACnet network port's Poll Service 'Busy Time' property to be greater than 100%?

This is an example:

Environment

I/A Series G3 BACnet

Cause

Two threads are used for polling for a  BACnet port's Poll Service. 

Resolution

The Poll Service is a common component for typical field bus drivers including BACnet. 

The Niagara Ax Drivers Guide defines the Poll Service's Busy Time property as:

Displays a percentage of time spent by the poll thread actually polling points, across all poll buckets. Includes (in parentheses) a ratio of “(time spent polling/total time since statistics were restarted)”. Given a small amount of time is spent transitioning between poll buckets, and with the thread sleeping to evenly space out polling messages, it is unlikely to ever see Busy Time reach exactly 100%. However, any percentage above 95% indicates that the poll thread is basically spending all of its time actually polling. 

In the case of the Poll Service for a BACnet network port, because two threads are used for polling, it is possible to see a Busy Time approaching 200%. In this case, divide the Busy Time in half to get an average busy time for each thread.

 

 

In the case of the Poll Service for a Bacnet network port, because two threads are used for
polling, it is possible to see a Busy Time approaching 200%. In this case, divide the Busy Time in half
to get an average busy time for each thread.
actually polling.
However, any percentage above 95% indicates that the poll thread is basically spending all of its time
actually polling.
to evenly space out polling messages, it is unlikely to ever see Busy Time reach exactly 100%.
However, any percentage above 95% indicates that the poll thread is basically spending all of its time
actually polling
to evenly space out polling messages, it is unlikely to ever see Busy Time reach exactly 100%.
However, any percentage above 95% indicates that the poll thread is basically spending all of its time
actually polling.
Given a small amount of time is spent transitioning between poll buckets, and with the thread sleeping
to evenly space out polling messages, it is unlikely to ever see Busy Time reach exactly 100%.
However, any percentage above 95% indicates that the poll thread is basically spending all of its time
actually polling.
Includes (in parentheses) a ratio of “(time spent polling/total time since statistics were restarted)”.
Given a small amount of time is spent transitioning between poll buckets, and with the thread sleeping
to evenly space out polling messages, it is unlikely to ever see Busy Time reach exactly 100%.
However, any percentage above 95% indicates that the poll thread is basically spending all of its time
actually polling.
Tags (1)
Labels (1)
Version history
Revision #:
1 of 1
Last update:
2 weeks ago
Updated by: