Hi, I am a beginner with LOGO programming.

My aim is to continously calculate a (delta) anloge input value within a (delta) time periode (15 min).

When the conditions are within my requirements, I want to get a dig. pulse

I there anyone that could give me a hint to solve this?

Thank You for the answer. Yes, I can explain.

If we say that I want to calculate every 5 min, then LOGO! have to remember two values plus 1 actual value (as I think)

What is possible in the LOGO! system for that? 

We are not talking past each other.

When I posted my first question, I was thinking that the requirements of the test setup was continously (ie every minute).

I have not clearified if we do accept minimum update time interval like 15 minutes.

If we do, then you have described a solution. For now, thank You.

OK, I can explain in more details.

This is a cycling test (warm/cold) and we will measure one temperature.

Test criteria for stop heating is when temperature not rise more than 4 degr. in 15 minutes.

When I said continoulsly, I was thinking of a criteria time update-check interval of max 5 minutes.

But, as I said in the other post, we are checking what is the minimum acceptable time interval for the test.

To calculate ds/dt you can use MaxMin as shown in the attachment. They can be cascaded with analog markers, if you need several values. In the second line you see some comparators as example. I don't know, what you want to compare.

Look also to the Analog watchdog. This special function saves the process variable of an analog input to memory, and sets the output when the output variable exceeds or drops below this stored value plus a configurable offset.

Maybe the program can show you the right direction to a solution.

Regards, Scorp