Success Story

Success Stories

Modbus Gateway Integrates Cleanroom Application with BMS

Contemporary Controls recently helped a customer complete Modbus to BACnet/IP integration in a cleanroom application. A mechanical contractor was developing a building management system (BMS) for a cleanroom installation which included optimizing the operation of 105 fan filter units (FFUs). The 105 units service one building with two cleanrooms that house eight separate rooms. The FFUs, from AirCare Automation, Inc., a leading supplier of cleanroom FFU controls for regulated air-control environments, used two Contemporary Controls' BASgatewayLX Modbus to BACnet Gateways (models BASGLX-M1) to convert the Modbus RTU protocol to BACnet/IP.

The senior controls engineer in charge of the BMS install turned to Contemporary Controls to create Modbus device profiles and complete Modbus to BACnet mapping to enable each FFU to monitor and control data points, such as Run-Stop, Speed, Tach Feedback, Sensor Input, Default Speed, and Default Run-Stop.

The cleanrooms contain 58 FFUs with 348 points supported by the first BASGLX-M1 and 47 FFUs with 282 points supported by the second BASGLX-M1. Contemporary Controls created a device profile for the FFU to map the Modbus data points to BACnet objects and replicated it 105 times with unique Device instance, Name and Modbus Device ID for each FFU. With the BASGLX-M1's virtual routing, each FFU appears as an individual BACnet device to the BACnet headend, a Distech - EC-NET 4.10.

Contemporary Controls created Modbus device profiles for the FFUs:

  • One profile housed the 58 FFUs with 348 points
  • One profile housed the 47 FFUs with 282 points

"Contemporary Controls' support team made this integration extremely simple and the documents on the website were helpful and reduced stress to help prep integrating the Modbus devices," said Justin Li, senior controls engineer in charge of the BMS installation.

The BASgatewayLX has one 10/100 Mbps Modbus TCP and BACnet/IP Ethernet port and an opto-isolated Modbus EIA-485 serial port for Modbus RTU or Modbus ASCII devices.

Up to 100 Modbus serial devices represented by up to 1000 polled points can share the Modbus EIA-485 port on the BASgatewayLX. BACnet COV notification is supported on 200 points (100 Analog and 100 Binary points). The virtual routing feature in the BASgatewayLX allows each connected Modbus device to appear as an individual BACnet compliant device for easy identification. Modbus data points from Modbus Serial or Modbus TCP devices can be mapped to BACnet objects.

Integrating a Modbus device to BACnet requires a device profile for each Modbus device. Contemporary Controls maintains a library of common device profiles available for download. If the device profile is not available, Contemporary Controls will provide it upon request free of charge.

For more information, visit the BASgatewayLX product page.

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