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Old January 20th, 2018, 07:15 PM   #1
bguinn
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S7 414 Load Memory RAM full

I have an S7 414 with a 1MB card. The line has been running fine but I needed to added some analog inputs to one of the ET200SP profinet modules. I physically added the module, then added to the offline hardware configuration. I then went to download the new hardware configuration, I got a warning of a bottleneck and needed to compress. I told it to compress. It compressed then started the download, put the processor in stop and started loading. It then popped up and said memory was full and download would be aborted. After this, the processor would not go back to run. I tried downloading the original hardware configuration with the same results. I then turned off power to plc, pulled the memory card. This cleared the card. I then tried to download again with 0% showing on load memory ram. I started with hardware configuration this increases load memory to 34%. I then download all DB's, which increases load memory ram to 69%. I then try to load OB's, FB's and FC's. I run out of memory before all are loaded.

Somehow there is a program on it after the cleared memory is put back in but it is not the correct program.

I have ordered a 2MB card but really want to know why it is needed now?

I have 4 questions,
1) If I can't load it back in, how did it all get there in the first place and be operational?
2) Since it was all there in the beginning why won't it go back on?
3) What or where is the program on the card coming fromwhen it says 0% load memory ram used?
4) What am I doing wrong?

HHHHHHEEEEEELLLLLPPPPP!!!!!!!!!
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Old January 21st, 2018, 02:30 AM   #2
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I assume your "1MB card" is an EEPROM memory card and not RAM memory card. Below, "memory card" refers to the EEPROM memory card. The RAM memory card would simply be an extension of the Load RAM of the CPU.

1) The memory card was loaded with a USB PROMMER, and, potentially, not all blocks were loaded, and the rest were downloaded with STEP 7 to the Load RAM in the CPU. This means some of your blocks reside in the memory card and the rest in the Load Memory RAM.

2) All blocks you try to download will go to the Load RAM of the CPU and not the memory card. If your Load RAM is smaller than the total of all the blocks you are attempting to download, it will not fit.

3) If the Load RAM memory is 0%, then the whole program resides on the memory card. It does not transfer to the Load RAM of the CPU.

4) a) Use a USB PROMMER to write the new program to the memory card
b) Buy a RAM memory card with enough space for the whole program and download the whole program (but you will be relying on battery backup).
c) buy a CPU with enough Load RAM memory for the whole program, download, and perform a "Download User Program to Memory Card" or rely on the battery backup.
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Old January 21st, 2018, 02:35 AM   #3
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PS: If the correct program is on the memory card, you should be able to put it in, perform a memory reset, and then everything should be the way it was before. If you download only the HW Config and the blocks you modified, it should fit in the Load RAM of the CPU. The draw back is, if you lose power with a dead battery, the program will revert back.
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Old January 21st, 2018, 09:08 AM   #4
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Thank you for the response.

I was finally able to talk with the OEM and was able to solve the problem. I'm fairly new to Siemens and the s7 400 is even more different.

I put in a 2M card and loaded the program to the memory card. Still trying to figure out how all the memory is alocated on these things. By doing this, all the Load Memory RAM was freed up.

It looks like if you just use the download button, it gets loaded in RAM, therfore if power and battery are lost, so are any changes you have made.

Now the only thing I have to worry about is if my DB's were updated enough to allow the machine to run correctly. Guess there's not much I can do about that until they run tomorrow.

Do the s7 300's work the same way?

I also need to go through the plant and make sure I get a good backup of the DB's. Isn't that as simple as going online, copying all the DB's and pasting them back into the offline file?
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Old January 21st, 2018, 09:33 AM   #5
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There is FAQ from Siemens about the memory concept of the S7-400, maybe it's helpful. It's a little bit different to the concept of the S7-300 (except S7-318 which is internally a S7-400):

https://support.industry.siemens.com...n/view/7302549
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Old January 21st, 2018, 09:57 AM   #6
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Most of that makes since, but I'm still trying to figure out for sure which card I have. It says flash on the card but when you check the processor properties, after a download it loads into what is called the RAM area. This data is lost when the card is removed. If I load to card, then that data stays when the card is reinserted. Still all a little confusing to me. Didn't have to worry about memory space and alocations when progressing AB.
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Old January 21st, 2018, 10:13 AM   #7
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I think your confusion lies in the flash card instead of ram card.
Both of these are available. Sounds like you have a flash card
Buy a ram card then you can download at will like you do with AB
But keep your batteries in good shape.
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Old January 21st, 2018, 10:19 AM   #8
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The type of card is printed on the end of the card, you can read this even when it's inside the CPU. If I remember correctly, there is something printed on like RAM or Flash EEPROM card. Definetively clearly to identify.

Removing / inserting the card is only allowed when powered off.
The program from the flash card is only loaded into RAM memory, when you have a non-battery backuped power failure. When there is a battery and battery is ok, then with this power the program is kept in RAM memory even without external power.

And yes, the memory concept of the S7-400 is a bit complicated. I was playing around with a S7-400 in my office, to test how it works, what memory areas get lost on cold start, how to save parameters when using a Flash memory card and so on.
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Old January 21st, 2018, 10:28 AM   #9
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You are correct, it does say FLASH on the outside. It is just confusing that it shows as RAM in the processor properties online.

If I use a RAM card, can I still do the so called online editing or does the processor have to stop? I have found that any time a Siemens processor goes through STOP while downloading, you are about to get screwed.

I always remove power power before removing any kind of plc module. This comes from the AB plc5 and slc500 days. They didn't like hot swapping at all.
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Old January 21st, 2018, 11:00 AM   #10
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Quote:
Originally Posted by bguinn View Post
If I use a RAM card, can I still do the so called online editing or does the processor have to stop? I have found that any time a Siemens processor goes through STOP while downloading, you are about to get screwed.
The RAM card extends the load memory. Parts of the program are loaded into working memory which is part of the CPU and cannot be extended. It depends on the CPU type how much working memory is there. If you check the blocks properties inside the Simatic Manager, you can see how much working memory your program is using.
If your are on limits of the working memory, you need to buy a bigger CPU. But if you have a Flash card now, I'd guess when you use a RAM card your problems are gone.
But check this out, as the RAM cards are not cheap.

The handling with RAM card is easier, as you don't need to go to Stop mode to copy the program to flash card after you've made your changes (and you cannot forget this step).

But as mentioned, you rely 100% on the battery. This needs to be changed regularly, and I'd recommend to add an alarm message when there is a battery failure. You can get the status of the battery LEDs by SZL/SSL requests from plc program.
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