Issue
Once the occupied cooling and heating setpoints are written from a BMS, the user is not able to change the setpoint from the room controller
Product Line
EcoStruxure Building Expert, EcoStruxure Building Operation
Environment
- Automation Server
- Enterprise Server
- SE8000 Series Room controller
- Viconics branding VT8000 Series
- Multi Purpose Manager (MPM)
- BACnet
Cause
By default, the occupied setpoint value is written to Room Controller with priority level 16 by the BACnet front end. Attempting to change the setpoint locally using the up and down arrows on the SE8000 Room controller will not be allowed since the Room controller uses the relinquish value internally (priority 17) which will be automatically overwritten by the BACnet front-end.
Resolution
The work around is to release the BACnet front-end control over the BACnet object using a LUA4RC script. The script can be uploaded using one of the following two methods:
1 - Uploader Tool
A USB cable is required to upload the script. The uploader tool can be downloaded from the Exchange
2 - BACnet
The script can also be directly uploaded via BACnet using the "Description" field as shown in the image below
if (ME.AV92 == 6 or ME.AV92 == 7) then ME.AV39_PV[16] =nil ME.AV39_PV[10] =nil ME.AV40_PV[16] =nil ME.AV40_PV[10] = nil ME.AV92_PV[17] =0 end
Where,
- ME.AV92 is the Keyboard value
- ME.AV39 is the Occupied Heating Setpoint
- ME.AV40 is the Occupied Cooling Setpoint
Using this method, the script can be uploaded to multiple SE8000 Room Controllers by following the steps in Bulk Lua4RC upload via BACnet (Mass upload)
For more information about Lua4RC, refer to the Lua4RC Programming Guide
