Warning
Potential for Data Loss: The steps detailed in the resolution of this article may result in a loss of critical data if not performed properly. Before beginning these steps, make sure all important data is backed up in the event of data loss. If you are unsure or unfamiliar with any complex steps detailed in this article, please contact Product Support Services for assistance.
Issue
A third party BACnet system is able to host values from a SmartStruxure Lite MPM but an MPM does not seem able to host values from another BACnet system or device.
Environment
BACnet
MPM-VA
MPM-UN
MPM-GW
Cause
SmartStruxure Lite Managers have full BACnet server capabilities, however BACnet client functionality is not native to the MPM and is currently only available through Lua programming.
Resolution
Integrating SmartStruxure Lite™ Managers with third-party BACnet server devices requires a BACnet client script. A sample script (download here) can be used to perform read and write operations to other devices via BACnet IP, however, a few tips and limitations must be taken into consideration before deployment on site.
NOTE1: The delay at the beginning of the script (if scl.sysclock() > 90 then) must not be removed or modified. Otherwise, the MPM will keep rebooting endlessly and would require restoring its factory defaults before gaining access to Building Expert again.
NOTE2 : The more points used in the script, The higher the MPMs CPU% Usage will be and the less responsive the MPM will be. Therefore, it is recommended to only read/write the necessary points and not all the points on the third party devices. Also, if some points are more important that others, the polling time can be increased to 60 seconds for example.
NOTE3: The more objects you have on the MPM, the less room you have for BACnet points. PGs, Trends and Events consume a substantial amount of CPU Usage so it is important to keep an eye on it as you add more points in the script.
NOTE4 : Run the script every 5 seconds or more if possible
Limitations:
- Reading/Writing to Multi State Values (MSV) is not supported
