CHANGING FROM REMOTE-RUN TO PROGRAM MODE WITH THE KEYSWITCH on a ControlLogix L73

[NotEinstein]

Hi,
I am curious to know what will happen to a Running 1756 ControlLogix L73 controller if the keyswitch is changed from Remote Run to Program Mode while online

 

[Ken Roach]

Welcome to the PLCTalk forum community !

The short answer is: "The controller will go into Program Mode".

The Continuous Task will execute the remaining un-executed Programs for this scan cycle, then stop.

The controller will not execute any more Periodic or Event tasks.

The controller will send Program Mode state messages to all active I/O connections. Most output connections go to OFF or zero outputs, and most VFDs fault or stop, when you go to Program Mode.

The controller will go into Program Mode and wait. You can perform edits, make nonvolatile memory save/restore actions, or just leave the controller idling.

 

[NotEinstein]

Thanks very much Ken ...

 

[Phil Buchanan]

Do some in-depth research and make sure you understand what it "will" do.

As Ken said most physical outputs turn off and most drives fault but this is not always the case.

For example, on many of the 1756 series output cards, you can choose what state the outputs go to when in program mode and when the controller faults.

This can be selected on an individual or a group basis in most output modules.

In other words, some outputs that were not on during run mode could turn on when switched to program mode depending on how it's set up and depending what the output is wired to this could be dangerous so just something to double-check.

These options can be set programmatically or with the RS Logix 5000 or Studio 5000 software packages.