Logix executing AOI sheets on sequential scans

It appears to me that Logix is improperly executing sheets of an AOI in sequential scans instead of the same scan as the main program. To test this, I created SheetTest.ACD

I have an AOI called SheetTest_AOI. It consists of 5 sheets of function chart logic. The only thing it does is pass a value from the first sheet to the last sheet. The main routine is running 1000 msec and calls the function block routine SheetTest, which only has the SheetTest_AOI in it. Unfortunately I cannot upload the code, so I attached bitmaps.

I created the FT ME version of an HMI to see the result. When I change the input on sheet 1, I see the value I pass update on each of the sequential sheets in the AOI one scan later as you can see from the attached image.

Is this a Rockwell bug, or is there something that needs to be done in sheets or AOIs to make the value pass all the way through in one scan time?

It looks to me like it is behaving as advertised.


Try using connectors instead of references to control the order of execution, and see if the behavior changes.

• https://literature.rockwellautomati...{"num":3543,"gen":0},{"name":"XYZ"},52,678,0]
• https://literature.rockwellautomati...{"num":3555,"gen":0},{"name":"XYZ"},52,405,0]

As advertised? I have not found anything in Rockwell literature that states each sheet will execute on its own scan.

Now I see. It is the IREF that latches. I will try connectors.

Thank you for the response

Connectors fixed it