Cost estimation Trending WinCC

[Cryotechnic 0]

Recently they did un update of the automation of one of our plants. They changed to Siemens S7 plc and WinCC/Step7. Trending is very important for us because, most of the corrections we make to control the proces are based on the trends we see of the proces. Allthough the most important procesparameters are logged and vissible in a trend, there are still procesparameters who are not logged. - What are the limitations of logging of data in winCC? - If you reach the max number of data that's been logged, is it possible to expand this? If yes, what are the costs and what do we need to expand this? - What are the costs of data logging in WinCC? Let's say the cost of trending 10 different procesparameters with a sample time of 10 sec? - I have understand that data that is been logged is saved in a SQL database and when it's displayed in a trend it's ben restored from there. Is this correct? - What is the relation between Mbytes and number of loggings/sample time? I mean, if you log 1 parameter for 24 hours, and a sample time of 10 sec, how much MB will that take? Thanks in Advance, I hope someone can help me.... Cryotechnic