Posted 8 Jun 2015 Hello, When using a 4-20mA configured Flex IO 1794-IE8/A with Controllogix, I used to get a raw input of -770* (could be -7701,02,03) when the wires weren't landed. Now with an 1794-IE8/B, I'm only getting the same reading as I would with a 4mA signal, which is a raw input of 0. I know there's an "underrange" bit for the status now, but it gets activated at 4mA or below, so if your instrument is at 4mA, it will alarm as underrange, even though it is a real reading. I see a slight bounce up and down for a 4mA reading, but I really don't want to add a delay timer for the underrange alarm. Anything I'm missing to get this -7701 reading back? Share this post Link to post Share on other sites
Posted 9 Jun 2015 Have you checked the module configuration? Open the RSLogix5000 file, locate the module on the left hand side (under IO Configuration), right click on the module, then select Properties. Make sure the old module and the new module are set up the same way. You need to set up each channel. According to Rockwell, there are some differences between the 1794-IE8/A and 1794-IE8/B, see pg. 63 here: http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1794-um002_-en-p.pdf Share this post Link to post Share on other sites