AOI For Logix5000

Has anyone developed an AOI for FBD to monitor Processor Scan Time? I have a existing project in ladder that I need to convert to FBD and it has code in the ladder that monitors scan time. I tried to create one but the ST logic doesn't like the following GSV(Program,MainProgram,MaxScanTime,MyTAG);

When you create an add-on intruction, it's available in all three programming types (lad, st, fbd). It doesn't matter what the AOI was written in. Why don't you use the existing ladder code to develop the AOI?

I am removing lad from the controller and the GSV is not available in FBD.

I am also using V16 firmware for Controllogix 5000.

etressbc said:

Has anyone developed an AOI for FBD to monitor Processor Scan Time? I have a existing project in ladder that I need to convert to FBD and it has code in the ladder that monitors scan time. I tried to create one but the ST logic doesn't like the following GSV(Program,MainProgram,MaxScanTime,MyTAG);

Click to expand...

I got it. It is GSV(Program,THIS,MaxScanTime,MyTag);

You wanted Processor scan-time - your GSV is accessing the Program scan-time. There is a TASK object in the GSV, this will get you the processor scan-time if you use it in the Continuous Task.

Also, you are getting MaxScanTime, this will be much larger than the actual scan-time (LastScanTime).

But I have to ask why you need this information? If you are getting this to guard against excessive scan-times, you can rely on the Task watchdog (use a fault routine if you don't want the processor to major-fault).

If you are OK with scan-times to mS resolution, then the attached rung achieves this with less "overhead" than using an AOI and GSV instructions.