The Schneider Electric BACnet Direct Digital Controller b3804 is a compact, freely programmable BACnet MS/TP controller offering a higher-density I/O configuration for control-intensive HVAC applications in commercial building automation.

• Part Number: b3804
• Protocol: BACnet MS/TP
• I/O: Expanded universal I/O (configurable analogue/digital inputs and outputs)
• Programming: Freely programmable via StruxureWare Building Expert
• Power Supply: 24 VAC/VDC
• Mounting: DIN rail or direct panel mount
• Compatible: Schneider Continuum, EcoStruxure Building

Deployed where a large number of I/O points is needed in a single field controller — such as primary/secondary chiller plant, large multi-zone AHUs, and central utility boards. BACnet MS/TP peer-to-peer communication allows b3804 controllers to share data across the floor bus without supervisor intervention. Supports complex sequences including chiller sequencing, cooling tower staging, and heat recovery optimisation.