What can cause AB PLC5 to go into program mode?

[rPraveenkum]

At what rate you logging the data in the visualization software

 

[davidg68124]

Wow,

you are thourough with your logging. But as has been said before, it is unlikely the processor did this by itself.

In your trending, is there other seemingly unrelated data that shows any anomolies?

David

 

[tomalbright]

Are you trending s1/7? That might show if the keyswitch was switched from REM.

 

[wildswing]

We lump these processor status words togther with our normal process data. This group has an update rate of 5 seconds.

S:1/7 did not flip, but S:1/1 (run mode) and S:1/3 (prog mode) did.

We got some new info today. After some further discussions with the tech on shift that night we found out that he had made the switch. I'll follow up further with him when he's back on his next day shift.

Thanks again. I appreciate all the replies.

 

[frw312]

Thats right. I have a few PLCs that are in foreign plants where there is no one on the maintenance staff that has enough PLC experience to trust that they would be able to solve PLC problems. So I put in some extensive diagnostic screens in RSView - and one screen allows them to view the processor status, clear a fault code, and place the PLC back into remote run (provided the key is in REM), as well as set the processor time. It is simply a matter of creating the RSView tags to read/write from/to the status file bits. I also added the RSLadder (ladder viewer) Active X to a diagnostic screen so that they can view the running ladder from withing RSView, and with a small bit of VB programming there is a password protected button that allows a re-download of the program to the PLC. I don't normally put those features into an RSView app, but in this case it has saved me at least one trip across the pond.

Alaric,

I came across this post while seraching on the clock changing problem. That looked like a nice feature to add to an HMI. I tried going to the data table and clearing S1/1 or seting S1/3 to get it to go to the program mode and when I cleared bit 1 or set bit 3 they went back to their previous state. Do you have to change both in the same scan? What is the correct way to do what you commented on in this post? thank you for your help. frw

 

[OkiePC]

Perhaps the key switch is in RUN mode, preventing you from making the change. I think it must be in REM in order to remotely change modes.

 

[frw312]

the key is in remote (checked to make sure) and Rslogix shows it as remote online mode also.

 

[Ken Roach]

Keyswitch status bits are Read-Only. There is no effect if you set them in logic or using an ordinary data table write commmand.

Mode switching is done with specific commands that require user permissions and are checked against the physical mode of the keyswitch by the operating system.

Controllers CANNOT "switch themselves into Program Mode".

The only purpose for which I've used an HMI to set a controller into Program mode is one for which the next step was to perform an EEPROM save. The only HMI I've seen with this capability is the DH-485 protocol PanelView Standard terminals when used with SLC-500 controllers.

In those terminals, while you did appear to be configuring the PanelView to set a Status bit, the PanelView was actually sending a Mode Change Request command, not a Data Table Write command.

I have carefully read the post above the describes using RSView to switch controller modes, and I'm always willing to learn something new. But I'll bet that under the hood there's something else; Alaric also described using RSLadder to view the logic and actually perform a download to the controller.

 

[leitmotif]

THIS IS AN OLD RESURRECTED POST -
Original date was 10/06.

Interesting read though

Dan Bentler

 

[frw312]

Are those commands that you describe available to Rsview32? Since you can switch the plc to the program mode from RSlogic I figured they should be accessible from rsview32. I wanted to add this feature for the same reason as described in the post to allow operator or maintenance to get fault cleared.