What is the BACnet point attribute COV Increment and how to use it
The COV Increment attribute on a BACnet point is equivalent to the threshold attribute of standard Continuum Infinity inputs. When a Bacnet point is exported to other devices as a COV, its value must have changed by at least the COV Increment value since it was last exported before the new value is sent out. Using this attribute will decrease network traffic especially on the MSTP network if you are exporting frequently changing point values.
This attribute can be set on the BACnet point editor on the Basic alarms tab. If you have a Cyberstation prior to Version 1.8, setting this value from the point editor will not stay persistent in the controller after the controller is reloaded, it will default to 0. In order to keep the value after a reload, you will need to write a PE program to set the desired value after a reload. The program should be Autostart and Fallthru.
A sample of the program is below:
Line SetCov Writeproperty("Full Bacnet Path to Point", CovIncrement, "Desired Value") Stop
If you have several points that need the CovIncrement set, you would just add the additional lines into this program.
In 1.8 or greater, this program is not needed as these attributes get sent to controller on a reload. The initial COV increments still need to be added to point as they default to 0.