Posted 29 Dec 2015 Hello, Can you guys help me sort out what's wrong with this? info: I have never connected this PLC to a PC. I got it like that. I just powered it on and as you can see the led. few things are faulty. Also, I don't have batteries and MMC but it's okay. Even with a different CPU and CP it's the same thing. regards, 1 person likes this Share this post Link to post Share on other sites
Posted 29 Dec 2015 Put a program in it. Without batteries etc... its empty Share this post Link to post Share on other sites
Posted 29 Dec 2015 Thanks, are you sure that's the problem? Without a battery and MMC it's okay for an S7-400 CPU since it has got internal RAM. Share this post Link to post Share on other sites
Posted 29 Dec 2015 Hello Idir, have a look to next links: https://support.industry.siemens.com/tf/ww/en/posts/extf-error-of-s7-400-after-switch-off-the-plc/28924/?page=0&pageSize=10 dekor. Share this post Link to post Share on other sites
