ControlLogix scan sequence

Can anyone point me to any documentation that shows how clx platform handles IO, data update, and program scan? I need to know if data from the ENBT comes in asynchromously or at some predictable sequence.
Thanks,
DW

are you getting data produce/consume? if so it should come in at whatever you set your RPI to. If it is a large chunk of data use a Synchronous Copy command to receive in large chunks of data or send out large chunks of data. This will make sure you recieve all the data without worrying about getting data asynchronously. Find the CPS command in the help file. Sounds like this is what you are looking for.

ALL I/O coming into a CLX comes in asynchronously. All I/O follows the producer/consumer model, so the CLX sees it as it is produced at a rate determined by the producer. This is as true for a digital input module as it is for the ENBT. This is a significant departure from the SLC and PLC5 family, where I/O updates were rigidly defined.

Keith

For Digital modules see:
http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um058_-en-p.pdf Chapter 2

For Analog Modules see:
http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um009_-en-p.pdf Chapter 2

If you have a problem with asynchronous data transfer then check the General Procedrues manual and the AB Knowledge base at ab.com on data buffeering. The CLX is so dang fast that with most things it doesn't matter - but there are times when its needed.