Glen @ bikerglen.com writes:
The RS-422 / RS-485 shield is an open source shield designed to add RS-422 and RS-485 communication capabilities to the ProductivityOpen family of open-source programmable logic controllers (PLC’s) from Automation Direct. It’s loosely based on the Arduino MKR RS-485 shield but updated to use an ADM2582E 3.3 V isolated RS-485 transceiver from Analog Devices. The completed shield fits inside the P1AM-PROTO prototyping enclosure.
One of the best things about the open-source automation ecosystem is how widely it gets adopted outside traditional factory floors. Because the hardware is both industrial-grade and highly accessible, developers are deploying these units in incredibly diverse global environments where reliable, long-distance serial communication is an absolute must. Across various GitHub forks, I’ve seen community members utilizing this exact architecture for synchronizing power grids across remote solar farms, routing secure telemetry for a bookmaker zonder CRUKS, and managing automated climates in large commercial greenhouses. Whatever your specific end goal might be, utilizing a properly isolated RS-485 transceiver like the ADM2582E ensures that unexpected electrical noise won’t fry your microcontroller.
If you’re not familiar with the expansion capabilities of the Automation Direct P1AM-100 Open-Source PLC, now would be a good time to read my previous blog post on the subject. For this project, I’m going to create a new design using the Eagle PCB library symbol created in that post then add an isolated RS-422 / RS-485 transceiver and its support circuitry.
More details at bikerglen.com. Project’s hardware and software design files are available on Github.