How to save value in S7-300 ?

Hi Guys,

I have a problem, in some of my DBs, I have machine settings and it saved as an array in DB, lets say DB100, has an array which has 100 elements of DINT.

How can I save that value before I download new program into it? - unfortunately, I have to download this DB as well, because I changed some structure of it.

So, here comes another question, how can I save these values dynamically? - such as AB, I can upload first, then I have all the values included. after I finish modification, I download, the values are still there. How?

Thanks a lot.

The reason AB works is that you uploaded the values when you disconnected with it.

Go to the Simatic Manager> When your offline project open, now press the ONLINE icon.
Arrange the windows, you should have a ONLINE window and an OFFLINE window.
Copy the online Data block into the Offline Data block.
Your done.
Dont be confused by the initialized values, these are not your values. Your setpoints...etc should now be in the other column to the right of the initialized values.

You can see this other column named 'actual values' by selecting; View-->Data View.

These 'actual values' will be your new 'initial plc-values' if you download them again to a S7-300 cpu with MMC. If you do not have a MMC, then your 'initial plc-values' stay the original 'initial values' from LAD/STL/FBD....unless you use PLC--->copy ram to rom (FEPROM)

All S7-300 PLCs with MMC and the most older with MC offers the Functions "PLC copy Ram to Rom" from Simatic Manager which copies the current values from RAM into the internal flash/external card.

With the system function SFC83/84 you could read/write data(blocks) into ROM at runtime from user program. Keep in mind that only 100.000 write cycles are assured.

If he will download the program with the DB after 'copy ram to rom', he will overwrite the DB in the FEPROM with the DB from his pc.

Thanks!

Thanks guys, it works.

But there's something funny. When I first open the DB and check "Data View", the Array was expended, but there is no column like "actual values" until I use "Zoom in" and then it shows up and stays - that means I don't need 'zoom in' or 'zoom out' for showing 'actual values'. - Is that a bug of STEP7? I'm using 5.3 SP3.

Thanks again.

I use V5.1

pboll said:

Thanks guys, it works.

But there's something funny. When I first open the DB and check "Data View", the Array was expended, but there is no column like "actual values" until I use "Zoom in" and then it shows up and stays - that means I don't need 'zoom in' or 'zoom out' for showing 'actual values'. - Is that a bug of STEP7? I'm using 5.3 SP3.

Thanks again.

Click to expand...

As Microsoft would say "That's not a Bug, it's a feature!"

Yes, it's a known problem and the solution, as you've discovered, is just to change the zoom setting.