Hi

how do i calculate the number of records needed to display a 36 hour trend? The TIA help is not very helpful with regards to this. 
I have 5 REALS i need to log every 5 seconds, so how many records do i need.
Also, what is the advantage of using segments over a circular log? Isnt this just a circular log with "breaks" in the data? So what is the advantage and why would you use them?

 Hello skullcity,

skullcity

how do i calculate the number of records needed to display a 36 hour trend? The TIA help is not very helpful with regards to this. 
I have 5 REALS i need to log every 5 seconds, so how many records do i need.

>> 1 record/tag * 5 tags * 12 1/min * 60 min/h * 36 h = 129600 records

In a post in the German forum I found a link (WinCC V13 SP1) where you can find the "Number of entries per log (including all log segments)" which is maximum 50000. There was warning when I compiled it with 129600, but maybe better to use one archive per tag.

Murof

Hello skullcity

It depends on which Comfort Panel you use....

In "Entries per Log":

KTP400 -> 10000

700/900/1200 -> 20000

1500/1900/2200 -> 50000

-> These System Limits you can see in the TIA Portal Help System at:

visualize processes-> Performance features-> Performance features of devices -> comfort Panels

the logging System of the Panels and also of the Runtime is quite limited so you have to find a good way between logging cycle and the timespan you need.

Bye Murof

 Do the limits apply when using a USB stick to save logs?

I'm a little confused...

If log size depends on number of data records only, then why it changes when I change "Number of sequence segments" ? See attachment

Maybe 7200 "Data records per log" is data records per segment?

So, to configuration properly Basic panel 2nd gen I should to multiply "Number of sequence segments" by "Data records per log" and the result should not exceed 10 000 (limit of data records for this type of panel)??

Not clear at all...

And why there is no any warning in TIA, even when I set 500 000 "Data records per log"? Is this normal?

Results of test on real hardware:

Basic panels 2nd gen can record several (about 50) big (10 000 entries) sequental logs on USB flash, but reading of archive's content through "advanced" viewer on panel can even get stuck the panel.

One thing now I know for sure - simatic panels are not usable for long therm archiving.