Issue
A BACnet Schedule is working but not changing the point it is controlling
Product Line
Andover Continuum
Environment
- CyberStation
- Schedules
- BACnet command priority
Cause
A BACnet Schedule will by default, write to a BACnet point at a certain command priority level. However if that BACnet point is also being commanded by a higher command priority then the present value of the point will not change according to the Schedule.
Resolution
Example:
A BACnet Binary value is created and the operator wishes to set the value to Off. If the value is set by a Manual Operator then by default this will command the point to Off at command priority 10.
If a Schedule is then created and the point is attached to that Schedule, because a Schedule's default priority is 16, at the configured time, when the Schedule tries to change the point to On it can only command that point at command priority 16
The point itself always obeys the highest command priority which in this case is command priority 10 so the value stays Off.
To correct the above scenario there are two main options:
- Edit the Command Priority Tab of the BACnet Point and perform a Relinquish at command priority 10 to clear out that command, at which point the BACnet object will then defer to the next highest command priority (which in this case would be command priority 16)
- Edit the Schedule and change the command priority on the Schedule configuration page to an appropriately higher priority such as command priority 10.
NB. In cases where a point is written to at the same command priority as another object then the point will be controlled by whichever object wrote last...
