Posted 11 Jan 2019 Hello everyone, I want to know why the Y172 coil is ON / logic 1? whereas contact SM1 is worth OFF / logic 0? can anyone explain it to me ? Share this post Link to post Share on other sites
Posted 11 Jan 2019 Hello, according to your picture SM1 contact is Closed contact... basically it is negation Share this post Link to post Share on other sites
Posted 11 Jan 2019 40 minutes ago, sczot said: Hello, according to your picture SM1 contact is Closed contact... basically it is negation is SM1 a type of Emergency button that must use NC at first? Share this post Link to post Share on other sites
Posted 11 Jan 2019 @diraemon SM1 are Special Relay for Self-diagnostics Error. If it on that mean there are some error and vice versa. For your ladder program if no Self-diagnostics Error Y172 will be on. (Because SM1 is off but convert logic with NC contact). Share this post Link to post Share on other sites
Posted 11 Jan 2019 Thx you mr. @sczot and mr. @Wasan Share this post Link to post Share on other sites