lamaPLC: TTL to RS485 Module

The module is often listed as HW-097.

The onboard MAX485 chip is a low-power, slew-rate-limited transceiver for RS-485 communication. It is connected to 5.08 mm pitch 2P binding posts, which makes RS-485 wiring convenient. All the chip's pins are exposed and can be controlled and operated by the microcontroller. It operates on a single 5V power supply with a rated current of 300μA.

RS-485 is a type of asynchronous serial communication protocol because no synchronizing clock signal is transmitted with the data. RS-485 uses differential signaling to transfer binary data between devices. This differential signaling creates a differential voltage using positive and negative 5V supplies. The advantage of this method is its ability to reject common-mode noise.

RS-485 supports a maximum data transfer rate of 30 Mbps and can connect many slaves to a single master. The protocol allows up to 32 devices to be connected.

The module is suitable for Arduino and Modbus RTU applications. In this setup, the Arduino should use Tx/Rx TTL communication, while the standard Modbus A+, B-, and GND connections should be made on the other side of the module.

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