RsLogix 5000: How to detect effectively a Remote Mode.

Hi folks!

I need some helps in this problem. I am just trying to determine when the switchkey has been turned to Program Mode so that Scada shows on any display to any operators that PLC is in PROGRAM MODE. I have found using GSV instruction, classname: Controllerdevice, attribute name: Status, that some bits that this instruction yields regards mode in which PLC is in, say, RUN, REMOTE, PROGRAM. But this doesn't work 100%, sometimes when I turn the switch from REMOTE to RUN the PLC shows that it is on PROGRAM mode. If I turn the switch slowly, sometimes the program detects the exact position of the key (at times!), but if I turn the keys rapidly, my ladder program cannot detect this mode change in the PLC. Anybody has an workaround in order to detect 100% the exact mode that a Controllogix is in? How could I program my PLC so that it can report to any supervisory stations that PLC is in Program mode?

Thanks for your comments and helps

Froy

Sounds like you have your Scada communicating directly to the ControlLogix PLC.

If so, then using a GSV (which is a ladder scoped instruction) is scanned. If you take the controller off scan (place it in program mode), then you will not have that information.

If you are using RSLinx as your I/O server, I believe there is a tag that you can get from there.

Thanks for your kind answer.

I am using RSLINX Classic to communicate with ControlLogix 5000 plc. And you are right, I am using a direct tag from the PLC to read a mode operation and display it on my HMI applications (PANELVIEW and iFIX). And yes, they detect the PROGRAM operation mode of my PLC, but sometimes, they froze in REMOTE message. That is, the PLC scans the ladder and before it goes to Program Mode it executes the GSV instruction and successfully it saves the value of the mode in the tags HMI's use before PLC freezes. But normally it doesn't work 100%.

I don't know about RSLinx system tags. Where do I find information about it? Or there is another way to read PLS mode status on my HMIs?

Thanks again