Reference designs

This chapter will provide example designs for the W-BACnet module.

Reference design 1 - Power supply

The following design can be used as a reference for the power supply circuitry. It employs a buck converter to regulate the input voltage to 5 V, which is then converted to 3.3 V using an LDO. The 3.3 V rail can provide power to the W-BACnet module, while the 5 V rail can be used to supply, for instance, the RS485 driver circuit. See Pin assignments for further description of the module pins.

Reference design 2 - RS485

This section presents an illustration of an RS485 driver reference circuit. The 5 V provided by the power supply reference serves as the circuit's input power. DE1, TX1, RX1 and RE1 can all be connected to the module, with the relevant pins described in Pin Assignments.

NOTE: Voltage on RX1 must NOT exceed 3.3 V! Since the RS485-driver is using 5 V logic levels, a level shifting circuit (such as a resistor devider) must be used!

Reference design files

Electrical and mechanical design files are available at the W-BACnet Module support page.