Control Network Newsletter

October 2009: Free Configuration Tools for Commissioning Modbus to BACnet Mapping

Contemporary Controls has developed two off-line Excel VBA programs to assist system integrators in integrating Modbus register-to-BACnet object mapping for the BAS Remote. The first program called Modbus Profiler is used to characterize the Modbus device in a format usable for the second program called the Project Builder. Modbus serial devices attach to the MB port on the BAS Remote. Each Modbus device has a set of registers and each one of those registers has a description of the register that can be found in the user manual for the Modbus device. The system integrator builds a profile of the Modbus device in a spreadsheet by transferring over the register location, description of the register, the type of variable (16-bit or 32-bit) and if it is a read/write or read-only register. It is not necessary to list all the registers – only those that are to be scanned by the BAS Remote. Once all the necessary registers are accounted for, the profile is complete and can join a library of Modbus profiles.

The second step is to load the required profiles into the Project Builder. Up to 30 Modbus devices can be added to the project – with a project being defined as those devices being scanned by the same BAS Remote. The profiles for these devices can be the same or can be different. When devices are added to the project, each must be assigned a unique Modbus device address. An optional field exists for entering the location of the Modbus device which would be helpful when several of the same devices are being used. Once all the data has been entered, the Project Builder generates a scan list in a csv formatted file for downloading into the BAS Remote. Once loaded in flash memory, the BAS Remote is rebooted and begins scanning the Modbus devices.

In order to reduce configuration time, Contemporary Controls will develop Modbus profiles of the more popular Modbus devices such as energy meters. These Modbus profiles will be available for download from the company's web site along with the Project Builder software.

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