Modbus Server To Bacnet Client; Specific Gateway Introduction; Functionality - HMS Networks Intesis IN700-485 Series User Manual

IN700-485 Series

Modbus Server to BACnet Client

5. Modbus Server to BACnet Client

5.1. Specific Gateway Introduction

This section describes the integration of BACnet MSTP and BACnet IP devices or installations into Modbus RTU or
TCP systems using the Modbus server to BACnet client application of the Intesis gateway.
This integration allows a Modbus system to access the signals and resources of BACnet devices as if they were
part of the Modbus system itself and vice versa.
The gateway configuration is carried out through the configuration tool.
Figure 2. Integration of BACnet IP or MSTP devices into Modbus TCP or RTU control and monitoring systems

5.2. Functionality

From the BACnet point of view, the gateway continuously polls the installation or devices, storing in its memory
the values of the points that you previously configured to be read. With the change of value (COV) system, the
gateway can also subscribe to configured BACnet points, automatically receiving their values when they change.
On the other hand, from the Modbus point of view, the control and monitoring system reads and writes those
stored points.
This is possible because, inside the gateway, all BACnet objects of the server devices are associated with Modbus
registers. This makes the Modbus control and monitoring system perceive the BACnet installation (all the server
devices) as if it were a single Modbus device.
When the gateway polls the BACnet devices, if a non-response is detected, the corresponding virtual signal inside
the gateway will be activated, indicating the communication error to the Modbus system as error registers.
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