What is RS485?
RS485 is a common serial communication standard with features such as good noise rejection, long transmission distance, and multi-drop capability. It transmits data using a differential transmission method, which allows it to suppress common-mode interference. RS485 requires a pair of twisted-pair cables and two terminal resistors to eliminate signal reflection during long-distance communication.
What is the Modbus Protocol?
Modbus is a master/slave architecture protocol used for communication between devices over RS-485. It uses unique addresses for each slave device to execute commands from a master device. Modbus commands include a check code to ensure data integrity, and can be used to change values in registers, control or read I/O ports, and retrieve data from devices.
Raspberry Pi RS485 HAT Introduction
This dual-channel RS485 expansion HAT designed for the Raspberry Pi adopts an isolated transceiver to achieve isolation for RS485, which increases the reliability and anti-interference of data transmission in each channel. And it features embedded protection circuits such as a lightning and surge protector, a TVS diode, and power supply isolation to protect the Raspberry Pi development board effectively.
Besides, the order includes a screw accessory kit that allows users to tightly fix this board onto a Raspberry Pi controller.
Wiring Diagram of RS485 Expansion HAT and Laser Ranging Sensor
- Operating Voltage: 3.3V
- RS485 Transceiver: TP75176E
- Serial Chip: CH432T
- RS485 Communication Interface ×2
- Power Indicator: red
- TX Communication Indicator: blue
- RX Communication Indicator: green
- 120Ω Terminal Resistance: ×2
- Wiring Method: 5.08-3P pluggable terminal block
- Raspberry Pi 3B+/4B Supported
- Mounting Hole Size: diameter 2.5mm
- Dimension(Package Not Included): 56x65mm
- Dual Channel RS485
- Electrical & signal isolation
- Lightning & surge protection
- Transient voltage suppressor
- RX/TX data transmitting/receiving indicator
- Agricultural Internet of Things
- Warehouse Internet of Things
- Indoor and Outdoor Environmental Monitoring
- Lighting Control
- Security Access Control System
