Recommended workflow / BACnet persistence

In building automation projects, changes of parameter settings very often happen while programming and configuring the application.

It is recommended to adjust parameters like P, I, D or Hi-Limit / Lo-Limit, even Description texts, etc. without using the BACnet persistence as long as possible. As final step before handing over the building automation application, the BACnet persistence should be activated.

Normally the values are synchronized at start-up from the BACnet supplement to the PLC. If BACnet persistence is activated, values previously written from BACnet will overwrite values in the PLC.

The FB_BACnet_Server provides a variable eInitMode to define the direction of this synchronization:

• eInitReset: This value is set after a Reset to Origin was performed. BACnet objects in the stack will be removed and eInitMode will be set to eInitToPlc.
• eInitToPlc (default): Values are synchronized from BACnet to the PLC.
• eInitForceFromPlc: Values are synchronized from the PLC to BACnet.