Double Serial Device RS232 RS485 RS422 Ethernet Server Modbus to MQTT lot Gateway Multi-Host Polling USR-N520 H7 Version

Writes useless, garbage log files to your C:Drive every 300 milliseconds and fills it up EXTREMELY fast (in the high hundreds of MB per day). Avoid this product if connected to a network.

I had a couple of RS232 only serial Modbus Slave devices, that would not play well with others, even when connected via individual RS232-485 adapters. ie I needed to multidrop them due to a shortage of serial ports on the RTU I was programming, and they would not cooperate. This adapter fills the niche. Setting it up as a Modbus over IP Slave it accepts connections on a couple of user selectable ports, and translates the Modbus over IP commands to Serial Modbus RTU commands and spits them out its ports. Each physical port is uniquely addressable in the format 192.168.50.120:1502 and 192.168.40.120:1503 in my case, and the Serial RTU address can be specified as part of the message, so the end of line slave device doesn't know the difference between this device and a dedicated serial line. I tested powering the unit from USB (USB to barrel connection), but it also has terminals, and I'm using them for a bit more voltage headroom (USB 5V is at the bottom of its acceptable supply range) The web page for setup and the (windows) software you can download seem to duplicate each other - I used the software to set the IP address, then the webpage for subsequent tinkering. There's no diagnostics I can see of for example the message bytes passing through, nor is there a DIN rail mount, but these are small things, especially at this price point.

Has a tendency to need to be power cycled. At first I thought it was if it lost power and came up again before the DHCP server could be reached, so I put it on a UPS. No. Then fixed the IP address, again no. Then I thought it was the particular unit, and bought a replacement - still no. It stops working sometimes, and I cannot reach it by IP - and just unplugging power and powering on again, my data stream restarts. I am reading a serial device over telnet every second or a few times a second.

Serial to Network or Network to Serial. Does what you want and has a great utility that lets you see the data without needing to connect to another device to confirm you see data. Just what we needed.