Posted 15 Jan 2019 (edited) Does anyone have any experience with sending multiple RS-232 devices to the same PLC? My current set up has 2 RS-232 devices sending raw ASCII data to a 2-port Comtrol DeviceMaster EIP-2202 where it is then sent to the PLC via Ethernet/IP. The problem is that now I need to add three more RS-232 devices. Without buying more DeviceMasters, is there a way of adding the 3 extra devices to where the data from each device can be read separately? I know RS-232 is 1 to 1, but is it at all reliable to use a multiplexer? I've looked into and I think it MIGHT work, but I'm a little nervous about adding the extra complexity. Another option I was looking into was to somehow convert multiple RS-232 connections to a single RS-485, which from my understanding can support multiple command and listening devices and I would need to be able to address each different device. My comtrl supports RS-232/422/485. Thanks for any help! Edited 15 Jan 2019 by Walks Share this post Link to post Share on other sites
Posted 17 Jan 2019 What sort of devices are the ASCII devices ? Do they have any sort of handshaking (Xon/Xoff, or RTS/CTS) that could prevent them from transmitting at the same time ? In some applications a "code activated switch" would be appropriate. B&B Electronics (now owned by Advantech) makes a neat device they call a "buffered smart switch" that allows you to add a prefix or even do some polling, so you could tell each port's data apart.http://www.bb-elec.com/Learning-Center/All-White-Papers/Serial/Automatic-Serial-Data-Collection.aspx Share this post Link to post Share on other sites