HF Smallest Elfin-EW11/Elfin-EW11A-0 Networking Devices Modbus TPC IP Function RJ45 RS485 to WI FI Serial Server (EW11A-0 Whole Set)

Worked great for my PLC system. Powered by 24 VDC and connected to my ASUS wireless router. Instructions are a little confusing. It took a little bit of time of figure out that the 'local port' IP settings of the device must be changed to modbus IP port 502 from the default (or the modbus master must be set to use the default port). Serial port settings are 57600,8,1,NONE and am using RS485 half duplex on a short run of about 24 inches with no termination resistor. Wifi is 2.4Ghz. using WPA-Personal encryption. Great price point and I plan in using several more for other projects.

I'm only giving this 4-stars because even though they claim this will work as an MQTT server, and it is in the configuration, I could never get it to send a single MQTT message.But I finally found an excellent use for it: After not getting MQTT to work I thought I'd try using it as a plain Wi-Fi RS-485 serial server. I had my doubts that it would do that either, but it worked first time! I'm using it to wirelessly get data from an analog sensor, which I've connected to an analog-to-RS485 converter.

I purchased this for my pool. I connected it to my Pentair Easytouch controller, and run nodejs-poolcontroller on a Raspberry PI. This was incredibly simple to configure, and very inexpensive. And it allows me to have my Raspberry PI indoors, and not in the outdoor Easytouch panel.