6/13/2017 2:29 PM | |
Joined: 9/27/2006 Last visit: 9/1/2024 Posts: 12282 Rating:
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Hello David; Connecting a 4-20 mA signal to 2 different input modules can be done, but it requires much attention to details. - the original signal must be passive (2-wire), so the loop does not exceed its max. voltage limit. - the whole 4-20 mA loop must be floating (no grounding), which might interfere with the functionning of the PLC installations. - If any one of the elements in tthe loop fails or is left unpowered the whole loop will fail; no signal will be transmitted. It would be better to think in terms of a loop splitter that will connect to the instrument producing the orignial 4-20 mA signal and produce 2 (or more) identical analog values that would be connected to the different analog input modules in the loop.These signals are generally conditionned and isolated, so removing one of the PLCs will not affect the other. See for example this discussion on the forum, and various sources for loop splitters: https://www.acromag.com/catalog/198/4-20ma-isolators-splitters/4-20ma-splitters https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=2864794 https://www.laurels.com/qls.php Hope this helps, Daniel Chartier |
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