Waveshare Industrial 8-Channel Analog Acquisition Module, 0–10V, RS485 Modbus

The input range is configured via software using Modbus RTU commands sent over the RS485 interface. You must write to the module's configuration registers to switch between voltage modes (e.g., 0-5V) or to set it for 0-20mA current loop sensing. Refer to the official Waveshare documentation for the specific Modbus register map and command structure required for channel configuration.

Use a twisted-pair cable for the RS485 Data+ (A) and Data- (B) lines. Terminate the communication bus at both ends with a 120-ohm resistor across the A and B lines to prevent signal reflections. Ensure proper grounding and maintain the recommended cable length limits for your baud rate. The module's isolation helps, but best practice is to run the RS485 lines separately from power cables to minimize noise.

Power the module via its terminal block with a DC supply between 7 and 36 volts. The onboard regulator handles the conversion. Typical operating current depends on the number of active channels and communication load but remains within a low range suitable for industrial power supplies. Ensure your power source can provide clean, stable voltage, and utilize the included terminal adapter for secure screw-terminal connections.

Yes, the module supports current loop sensing, but it requires external precision shunt resistors across the input terminals to convert the 4-20mA signal into a measurable voltage. You must then configure the software scaling within your Modbus master or SCADA system to interpret the voltage reading as the correct current value. The module's high-impedance input is designed for this application.

You need a Modbus RTU master capable of communicating via an RS485 serial port. This can be a PLC, a PC with a USB-to-RS485 converter using software like Modbus Poll or custom Python scripts with libraries like pymodbus, or an embedded controller like an Arduino with a MAX485 chip. You will need the module's slave ID, register addresses for each channel's data, and the configured baud rate (e.g., 9600, 19200).