AutoGen_2558162

Hi everyone,

In your opinion, how many ways are there to implement a data capture using a counter in a PLC?

For example: I want to capture a data value every 2 seconds, and repeat this process 5 times (so, 5 captures with a 2-second interval).

Has anyone already implemented this kind of logic? If yes, I’d be interested to see your approaches or sample code.

Thanks for your insights!

 

Perhaps an AI agent may assist you to generate the code you hope for? Sample conversation attached. Co-pilot in Edge browser's side panel as collaborator. (refinements not included)

Note the questions my collaborator had on my query. This is a good indicator to which information is possibly missing.

The intent of your question is not clear to me. If this was a brainstorming session I would expect some materials that shows that you are an active participant. There is also no mention of which hardware platform is used. A general question may require a general answer which covers multiple controller brands.

I have asked AI to analyse your question for its intent. In essence the AI responded with the below text. For the moment I assume the AI's analysis is correct.

AI collaborator

The user’s question signals a few layered intentions:

1. Seeking Pattern Diversity

- The phrase “how many ways” suggests curiosity about implementation variety—not just a single solution.

- This implies a desire to compare architectural approaches, not just copy code.

2. Implicit Constraints

- “Capture a data value every 2 seconds” implies a timed trigger—likely using a cyclic task, timer block, or time-based interrupt.

- “Repeat this process 5 times” introduces a bounded loop or counter logic.

- The user may be exploring how to combine time-based sampling with count-based termination, which can be done via:

- TON timers + counters

- Cyclic OBs + internal state machines

- SCL loops with timestamp checks

- Hardware interrupts (less common in this context)

3. Collaborative Learning

- The tone (“Has anyone already implemented…”) suggests a peer-learning posture.

- He’s not asking for a turnkey solution, but for shared experience—possibly to refine his own design.

4. Possible Diagnostic Motive

- He might be testing how others handle edge conditions: timer drift, race conditions, or capture precision.

- Or he’s probing for best practices in modularity, reusability, or auditability.

My Opinion

It’s a diagnostic probe—likely from someone who has a partial solution and wants to benchmark it against others. He’s inviting architectural diversity, not outsourcing implementation.

Using an IEC-timer is the quickest way to implement your request. The timer can be substituted for any other mechanism that can calculate the passing of time. So also the counting can be done by a counter or (my preference) using an integer memory tag.

The timer concept is only as accurate as the cycling time of the PLC. An interrupt may be used instead. Cyclic of time day type interrupt is possible for a more accurate time measurement outcome.

Recording of the values may be in an array situated in a DB. But other mechanisms can be used to point indirectly to memory locations. The implementation would depend on the platform used.

On the S7-1200 and S7-1500 the data recording functionality (data logging) is also available. Most functionality you seek is therein integrated. 

Newer models offer the ability to record traces even if the PC is not connected.