Waveshare Industrial 8-Ch Digital Input & Output Module, DC 7~36V Wide Voltage Power Supply, Modbus RTU Protocol, Multiple Isolation Protection Circuits, Rail-Mount Support

I didn't receive any instructions on how to operate this device but luckily I was familiar with Waveshare products and knew they would have a wiki with software and example code. Search the web for “Waveshare Modbus RTU IO 8ch wiki” and it should be one of the top results. This wiki includes a download link for Windows software to control this device. It also includes all the commands for the device.I picked up a RS485 to USB adapter, also from Waveshare, and was able to communicate with the device on a Linux computer. The default baud rate is 9600 8N1. Note that you will need to be able to send HEX commands using serial, I found the program “moserial terminal” provides a nice graphical way to send and receive HEX data. It is also possible to write a Python script to interface with this device. The wiki includes sample code to get started.I wanted to see what IC’s were used for this device so I opened it up and included a few photos. The main microcontroller is a STM32F030C8T6. The digital outputs use a ULN2803A darlington transistor array capable of 500mA up to 50V. Optical isolators are used to isolate this and the STM32 micro. For digital inputs optical isolators are also used. There is an isolated 5V 1W DC-DC regulator and a gas discharge tube. This design is fully isolated and the circuitry looks nice and neat.Overall this is a great device that I would recommend for anyone looking for isolated digital IO.

La documentación es buena, y el producto funciona como se espera

Lots of overload protection. Wide voltage range. Very convenient for doing prototyping work.