interlocking

hello i need help interlocking two doors so that both doors cant be open at the same time. So once one of the doors is open, the other must remain closed, until the first door is closed again. The doors are dock doors so they slide up and down. i need to know what the ladder logic looks like for this project. If anyone could help me it would be greatly appreciated. thanks.

mike.

It might be helpful for you to picture how an interlock like that is done in a hardwired application. A reversing starter has the same requirements. They are generally interlocked mechanically as well as electrically. Study the wiring diagram to see how the interlock works, and do the same thing in ladder logic for your application.

To get anything more specific, you'll need to include more details, such as how the doors are being actuated and what sensors are available to indicate the states of the two doors.

It seems to me that this question, or one quite similar to it, has been posted more than once in the past few weeks. Is this a lab assignment for a PLC course you're taking?

It seems to me that this question, or one quite similar to it, has been posted more than once in the past few weeks. Is this a lab assignment for a PLC course you're taking?

Click to expand...

Seems racinilodge has asked this before...
http://www.plctalk.net/qanda/showthread.php?s=&threadid=1322