krystian

Thank you for your reply. PLCs are not old, about one year. Worked in dryconditions in the room. They are in very good condition. I have another problem withonline verification. Port RS232 is used for applications and blocked. As I writing, does not work "i" button. Therefore, I can't unlock the port RS232 to test the PLC online. But in the second PLC, RS232 port is unlocked. When doing a command by the keyboardonline, everything is working properly. Is there a way to "hard reset for example, by setting the jumpers?

Hello Everyone. I have two M91 PLC. Today in one of the PLC stopped responding buttons"and","+ -" and enter. The machine that is supported by the M91 stopped working. I had a spare second M91, so I decided to replace it. Unfortunately, in the second M91 I noticed that the buttons do not work "# 1 ", "i". What could be causing this? Is this a problem on the PLC or machine. I tried to restart the driver,pulled out battery backup but it does not any change. I changed the button in U90Ladder assigned to another in order to try out and after changing the function worksproperly. Has anyone had a similar problem? Thank you for all the answers.