Modbus to BACnet/IP
Building management systems speak BACnet. Meters, chillers and packaged plant often speak Modbus. The Gateway appears on the BACnet network as one device whose objects carry the Modbus tags.
Typical use case
A BMS integrator needs energy or plant values on the BACnet network, and the equipment vendor supplies Modbus. Rather than a hardware protocol converter per panel, one gateway presents all of them.
Configuration approach
Object mapping
Each tag becomes a BACnet object. The Gateway suggests the type — Analog Input for a measurement, Binary Input for a status — and you can override it.
Instance numbers
Instance numbers can be fixed so they stay the same when tags are added later, which is what a BMS expects.
Object properties
Object_Name, Description, Units, Present_Value, Status_Flags and Reliability. Units are derived from the tag's engineering unit where it is a common one.
Discovery
The device answers Who-Is with I-Am, and serves ReadProperty and ReadPropertyMultiple.
Questions engineers ask
What happens to a tag that stops reading?
Present_Value holds its last value, the FAULT status flag is raised and Reliability reports a communication failure, so the BMS can tell a stale value from a current one.
Can the BMS write a setpoint back?
No. Every write service is refused; the gateway is read-only towards the plant.
Build a Modbus to BACnet/IP gateway
Create a project, define the device and its tags in the Edge Logic Editor, and download a runtime to test at the plant.