RS485 Port for Raspberry Pi on Sequent Microsystems HATs

Sequent Microsystems HATs add a reliable RS485 Port for Raspberry Pi, enabling industrial-grade communication and automation. Each HAT includes a 1 Mbps RS485 transceiver with TVS protection and flexible DIP switch configuration. Whether from the Industrial Automation family—where ports are consistently located for streamlined integration—or from the versatile “Swiss Army” group combining multiple interfaces, these stackable HATs deliver robust connectivity for home, building, and industrial projects.

Why You Need an RS485 Port for Raspberry Pi

The Raspberry Pi includes several serial ports on its GPIO interface, but all of them operate at TTL logic levels. To communicate with industrial equipment or other devices over long distances, you need a proper transceiver to handle the RS485 standard. This is where Sequent Microsystems HATs come in: every one of them integrates a reliable RS485 Port for Raspberry Pi, ensuring your projects can communicate safely and effectively in industrial and automation environments.

Robust Hardware Design

Each Sequent Microsystems HAT includes an RS485 transceiver rated up to 1 Mbps, connected to a pluggable terminal block for easy wiring. To protect your Raspberry Pi and connected devices, a dedicated TVS (Transient Voltage Suppressor) guards against voltage spikes and surges commonly found in real-world RS485 networks. With this design, the RS485 Port for Raspberry Pi is not just functional but also reliable in harsh conditions.

Flexible Configuration with DIP Switches

A six-position DIP switch provides configuration flexibility. Three positions determine the stack level when multiple HATs are used together, while the other three control the RS485 port settings. The 485-TERM switch activates the 120-ohm termination resistor required at the end of an RS485 bus. The TX and RX switches route the RS485 port either to the Raspberry Pi or to the local microcontroller on the HAT. This makes it easy to adapt the RS485 Port for Raspberry Pi to your system’s needs.

Standalone MODBUS Operation

One of the most powerful features is the ability to switch the RS485 port from the Raspberry Pi to the HAT’s onboard processor. In this mode, the card can be controlled directly from any PLC or industrial controller using standard MODBUS commands, even without a Raspberry Pi. This flexibility allows the same hardware to serve both as a Raspberry Pi expansion and as a standalone automation module.

Consistency Across Industrial Automation HATs

Sequent Microsystems offers a wide range of Industrial Automation HATs, and all of them feature the RS485 Port for Raspberry Pi in a consistent location for easy integration. On most boards, the port is placed in the lower-right corner, and in some designs the A and B signals are replicated to a secondary connector in the upper-left corner. This makes wiring simpler in stacked or panel-mounted applications.

Current Industrial Automation HATs with RS485 support include:

Eight 24-Bit Analog Inputs DAQ 8-Layer Stackable HAT for Raspberry Pi
Eight HV Digital Inputs 8-Layer Stackable HAT for Raspberry Pi
Eight MOSFETS 8-Layer Stackable HAT for Raspberry Pi
Eight Relays 4A/120V 8-Layer Stackable HAT for Raspberry Pi
Eight Serial Ports HAT 2-Layer Stackable for Raspberry Pi
Eight Thermocouples DAQ 8-Layer Stackable HAT for Raspberry Pi
Four Relays four HV Inputs 8-Layer Stackable HAT for Raspberry Pi
Four Serial Ports RS485 and RS232 Stackable HAT for Raspberry Pi
HALL Current Sensor DAQ 8-Layer Stackable HAT for Raspberry Pi
Multi-IO HAT 8-Layer Stackable for Raspberry Pi
RTD Data Acquisition 8-Layer Stackable HAT for Raspberry Pi
Sixteen 0-10V Analog Outputs 8-Layer Stackable HAT for Raspberry Pi
Sixteen Analog-Digital Inputs 8-Layer Stackable HAT for Raspberry Pi
Sixteen LV Digital Inputs 8-Layer Stackable HAT for Raspberry Pi
Sixteen Relays 2A/24V 8-Layer Stackable HAT for Raspberry Pi
Sixteen Solid State Relays 2A/24V 8-Layer Stackable HAT for Raspberry Pi
Smart Relays with Universal Inputs 8-Layer Stackable HAT for Raspberry Pi

Shown below is a typical Sequent HAT from the Industrial Automation family.

The “Swiss Army” Group of HATs

The second category of Sequent Microsystems boards can be described as the “Swiss Army” group. These HATs use a slightly larger form factor and are designed to include as many features as possible within the available space, making them exceptionally versatile for complex automation projects.

Design Characteristics

Unlike the Industrial Automation family, where the RS485 port is placed in a fixed location, the Swiss Army HATs route their RS485 port to a five-pin connector. This connector is shared with the 1-Wire interface, creating a compact, multifunctional design that maximizes the board’s utility.

This approach ensures that users can integrate multiple communication and sensor interfaces into a single board, reducing the need for additional hardware while maintaining a streamlined layout.

Board Examples

The following HATs are part of the Swiss Army grou RS485 Port on Building Automation HAT ms HATs Industrial Automation

Each of these boards combines multiple I/O and communication capabilities, allowing users to deploy them as standalone solutions or stack them with other Sequent HATs for expanded functionality.

Conclusion

The RS485 Port for Raspberry Pi built into Sequent Microsystems HATs brings industrial-grade communication directly to your Raspberry Pi projects. With high-speed transceivers, surge protection, flexible DIP switch settings, and standalone MODBUS capability, these HATs make it simple to integrate the Raspberry Pi into industrial, building, and home automation systems.