SD Trends

[cataliz3er]

Hello, I am using a Vision 570 for monitoring a number of temperatures, and I need a way to log the information.

I tried the sample "SD Card: Trend Read/Write/Append" but the problem is that in case of a power outage, I lose the information in the segment.

Is there a way to prevent this?

I was thinking of saving the temperatures to a data table, but then how do I display it on the trend?

If this has already been discussed, my appologies, and please redirect me.

Many thanks, Catalin Pop

[Simon]

If you want maximum flexibility I would suggest setting up a dual logging arrangement. That is, set up a data table log in parallel with the trend, and log the same values using both methods.

 

Use the trend to put the values on the screen, and save history.  Then use the datatable as a backup, where you can hold a buffer of data on the PLC and only delete if after you confirm it has been copied to the SD card.

 

There is no way that I am ware of where you can take data table information and load it back into a trend function.  However at least you would have the data and could retrieve it and view in Excel (or similar).