saving values of the variables in simatic step 7

Hi!

What is the easiest way to save some particular data (rapidly alternating variables changing with each cycle) in Simatic Step 7 package?

I need to save some of the variables in table every cycle (every 10 ms) to see what exactly is going on in the period of few seconds.

MissKrampus said:

Hi!

What is the easiest way to save some particular data (rapidly alternating variables changing with each cycle) in Simatic Step 7 package?

I need to save some of the variables in table every cycle (every 10 ms) to see what exactly is going on in the period of few seconds.

Click to expand...

Since no one has answered yet, I'll give it a shot.
Use a 10mSEC block (adjustable from properties) and send the variables to an array.
Make the array as large as you'd want.
Next cycle, index the previous captured variables within the array and store the new captured variables to the starting register.
Repeat the index to fill the array.
Each cycle, new variables come in and shift older variables one position.
Depending on the size of your array, the older variables get over-wriiten by the newer variables.
Hope this helps!
I'm sure someone else will jump in and continue this.
There may be a better/easier way.

Here's an example project that will log bool/byte/int/word/dword/dint/real variables.
Each variable is logged to its own db. The size of the DB determines how much data is logged. FB1 contains the instances of each variable you wish to log.

It's worth mentioning that there are some applications that can do this almost at that speed too, if my memory serves me PLCanalyzer Pro was a good one.
We also had an application that wrote the info into a database via TCP/IP for really hard to catch info.

rgds
David Askew
www.fast-automation.com
www.plccables.com.au