Fast analog data capture.

The module you are reading values from, what is the update rate of the analog input?  It is a specification you need to know before you waste any time getting duplicated copies of the input. 

In other words, is the physical input updating fast enough for your specified capture rate?

Is your PLC scan time faster than the analog update rate? 

If you know the answers to these questions and you are not wasting your time trying to read the same values multiple times, you can use cyclic interrupts to read the values much faster.

Typically the HS modules are able to read very quickly, but as was previously stated, putting the HS modules on the local PLC is a waste of money (my opinion).

So, I am assuming you have the HS module on an ET200SP remote I/O via profinet, and you have enabled IRT and configured properly.

The following links for documentation may help you figure this out in case you do not:

PROFINET System Description 

PROFINET with TIA Portal V15

Determination of the PN response time for typical configurations in the PROFINET IO

With the IRT configured so you can actually use the remote I/O analog input values at their maximum actual rate, you then need to read the data in a different PIP than the default process image buffer.

Cyclic interrupts will become your friend.  You can read the PIP several times during your program scan provided you do not do too much work in the interrupt OB(s) and take more time in the interrupt OB than you have before it interrupts again.

Read over the above documents and application example, then come back with questions after you have tried to configure your project.

One key thing in TIA portal for IRT (I found at least) is to configure the hardware in an test project.  Every time you make a network change and configure the topology / profinet settings, compile the hardware configuration to make sure it is in fact possible.

As you iterate over what is possible, you will need to reflect back on the specifications you need to meet and the hardware capabilities you have designated for use.  If you find you simply cannot get a hardware configuration to compile, enhance the technology if you can.  Try adding gigabit adapter to local and remote I/O, as one example of enhancement to meet your required specifications.

wmisiaszek

Hi!

I'm trying to capture analog signal, but a bit fast.
The task is to capture as much as possible readings in 2ms. Then get max from those numbers.
I'm using AI 2SG HS module.

CPU cycle time is obout 1 and somethink ms. So I manage to capture only 2 values.
Is it possible to overcome this and get more reading in 1 CPU cycle?