Posted 3 May 2020 (edited) i want to know the role of M2 is to enable the comparison function or it's anded with the output of the function. in another words if M2 is true and the output of the function is true then M3 is true, but what if M2 becoms false if it's anded with the output of the function then M3 is false , but if M2 stops the execution of the function M3 will remain true, so i need to know if it controllers the execution or it's just anded. Edited 4 May 2020 by m.rahmy Share this post Link to post Share on other sites
Posted 5 May 2020 It's ANDed, so any of the conditions in your ladder line goes false, M3 goes false, as well. Regards! Share this post Link to post Share on other sites
Posted 5 May 2020 note that coil instruction either sets and resets assigned memory location - every time it is scanned. output is true if condition is true (in this case it is ANDed) but if condition is not true, output will get reset as in this pseudo code example: IF (M2==TRUE) AND (D1 == 0) THEN M3 = TRUE ELSE M3= FALSE ENDIF Share this post Link to post Share on other sites