Posted 22 Jan 2020 Some PLC analog input cards (4-20mA or 0-10V) are listed as "RMS". I know what RMS means in math. But in the context of an AI module...why would someone choose this? Or, stated another way, what benefit does it have (either for the PLC user or even for the PLC manufacturer)? Thanks in advance, Arun Share this post Link to post Share on other sites
Posted 23 Jan 2020 I could see this for a discreet AC input or output module but I see no reason for an analog module. Do you have an example or a link to such cards? Share this post Link to post Share on other sites
Posted 24 Jan 2020 b_Carlton - Thanks for the reply. Here is a link to an example, SNAP-AIVRMS Arun Share this post Link to post Share on other sites
Posted 24 Jan 2020 Based on the link, it truly is a RMS module, the input can be 0-250VAC or VDC. Don't confuse this with a 4-20mA or 0-10V analog input module. 1 person likes this Share this post Link to post Share on other sites
Posted 24 Jan 2020 Yes pcmcartney1, I think you are right in that it has to do with measuring AC Voltage (because an average would be "zero"), so RMS is used. The voltage for 4-20mA and 0-10V is DC. Share this post Link to post Share on other sites
Posted 25 Jan 2020 Just don't run AC through that analog card input. Share this post Link to post Share on other sites