slc 5/05 Julian Date

In my plant, all production requires a Julian date code. I am looking for logic that converts the built in calandar in a Julian date for data logging.

Thanks

This example is for PLC5, but you should be able to use it with a SLC. Just use the correct Status file addresses for the date.

See THIS TECHONOTE from the AB knowledgbase at http://www.ab.com/

Alaric said:

See THIS TECHONOTE from the AB knowledgbase at http://www.ab.com/

Click to expand...

I need this in logix 500, I do not have the softwere for plc 5's
Thank you for the response

mollyputzer said:

I need this in logix 500, I do not have the softwere for plc 5's
Thank you for the response

Click to expand...

Sorry, my bad. I forget that not everyone that has Logix500 has Logix5. Here, I converted the PLC5 program file for you.

This is the same thing as what mgvol posted (adjusted for a SLC500), however, it also contains the look up table included in the technote file, which is essential for the calculation. Without the lookup table data the calculation won't work. The routine only needs to execute once a day.

This routine gives you the day of the year. Now technically, the Julian date changes at noon, not midnight. If you are using this convention then use a compare and a single shot to call the date subroutine only once at noon. If you are using a true Julian date then you need the number of days that have passed since Jan 1 4713 BCE. For that you can start with the Julian date of Jan 1 2006, which is 2453737, and add that as an offset and use a look up table for each years offset after that.

Thank you very much for your help

THANKS!!!

You guys saved me an afternoon of developement!

Its nice to see someone using the forum search function - and that a year later someone can still use the info.