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Short of memory CPU928B 6ES5928-3UB21

Created by: rherrero at: 9/1/2009 2:15 PM (10 Replies)

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9/1/2009 2:15 PM	Rate (0)
rherrero Posts: 26 Rating: (1)	Hi everybody, I'm getting short of memory in a CPU928B. In fact, Im already not able of making any change on the plc program and I cant save changes in computer and then download the whole PB to the PLC. Is there any way of knowing how much memory I have free in the PLC? In case the memory is full, what can I do? Memory card? Change CPU to 948? Thanks in advance.
rherrero Posts: 26 Rating: (1)
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9/1/2009 7:15 PM	Rate (0)
Pee Ell Sea Posts: 672 Rating: (57)	Hi, If the changes are small then a, Copy block to programmer b, Make changes in programmer c, Delete block in plc d, Compress plc e, Download block back to plc This way there will only be one copy of the block in the plc allowing for changes. Compress is really garbage collection of old copies of the changed block.
Pee Ell Sea Posts: 672 Rating: (57)
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9/3/2009 9:03 AM	Rate (0)
rherrero Posts: 26 Rating: (1)	Thanks Pee Ell Sea. The problem is that sometimes it's very handy for me to keep the original program in the programmer. What I need sometimes is to do some changes in the plc to test them keeping the original program in the programmer. If the new changes don't suceed I download the whole (original) block and that's it. (I have the original program in the plc again very quick). Thank you anyway for your idea, it can be very useful in an emergency moment. Yesterday I found a 948CPU in the store so, probably I'll try to install it in the next shutdown and see what happens.
rherrero Posts: 26 Rating: (1)
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9/3/2009 11:27 AM	Rate (0)
rherrero Posts: 26 Rating: (1)	What about memory card 374?
rherrero Posts: 26 Rating: (1)
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9/3/2009 12:24 PM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 11/12/2024 Posts: 3027 Rating: (1057)	rherrero What about memory card 374? Hello rherrero a 374 flash EPROM is not reallygoing to help you as its contentsis loaded into the RAM and that RAM is fixed to 64Kbyte. What you can do though is this: Your 928B has actually two internalRAM memory areas for the user program/data. There is the "normal" 64KbyteRAM to which you download your program and DB's and then there is the "hidden" so called "DB-RAM" whichoffers you an additional 46Kbyte of RAM purely for DB storage. DB-RAMis rarely used (I certainly never had the need for it, but I also never ran out of RAM), but it can offer you an easy way out of your problem without having to go for a948 CPU (assuming you haven't used the DB-RAM already) . If for example your whole S5 program is "made up" of 20Kbyte of DB and46Kbyte of code (i.e. "normal" RAM is full), you can free up 20Kbyte of "normal" by storing the DB's in the DB-RAM. Have a look at these links to learn more about it and how to use it: Loading DBs into the CPU 928B Moving data blocks with OB254/255 (CPU928B) Memory configuration of CPU 922 / CPU 928 / CPU 928B S5-135U CPU 928B manual - Version -3UB21 Alternatively, check if your program contains "leftover' blocks that aren't used/called anymore and remove them (online and offline). Make sure to check online too to see if the CPU contains additional "leftover" blocks that may have been cleaned up in your offline file but not deleted from the CPU. Finally, if you really want to replace the 928 with a 948, please pay heed to the differences as outlined in the link below: Replacing a CPU 928B with a CPU948 I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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9/3/2009 1:21 PM	Rate (0)
rherrero Posts: 26 Rating: (1)	Hi Fritz, Im very grateful for your help. Im gonna have a look to your links and try to do it.
rherrero Posts: 26 Rating: (1)
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9/3/2009 1:23 PM	Rate (0)
rherrero Posts: 26 Rating: (1)	By the way, is there any way of knowing how much memory is being used from both DB-RAM and normal RAM??? THANKS
rherrero Posts: 26 Rating: (1)
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9/3/2009 1:35 PM	Rate (0)
rherrero Posts: 26 Rating: (1)	Hi again Fritz, unfortunaly in the first link you gave me i read this: "ANSWER: In order to relieve the user memory, it is useful to store data blocks directly in the DB-RAM and not via OB181/OB254/OB255. However, this is possible only as of the end number 3UB12 for the CPU928. For this you must set the 0 bit to "1" in the system data word BS144 (EA90). The 0 bit has the following meaning:" This can only be done for cpu's 3UB12 and mine is 3UB12. However, i've found this RAM card: 6ES5377-0AB21 and somebody has said to me that this card can increase the internal memory of the CPU. I've nothing to loose so that I'm going read smth about it and see what happens. thank you again
rherrero Posts: 26 Rating: (1)
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9/4/2009 11:59 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 11/12/2024 Posts: 3027 Rating: (1057)	rherrero Hi again Fritz, unfortunaly in the first link you gave me i read this: "ANSWER: In order to relieve the user memory, it is useful to store data blocks directly in the DB-RAM and not via OB181/OB254/OB255. However, this is possible only as of the end number 3UB12 for the CPU928. For this you must set the 0 bit to "1" in the system data word BS144 (EA90). The 0 bit has the following meaning:" This can only be done for cpu's 3UB12 and mine is 3UB12. Hello again rherrero The 3UB21 (single Slot 928B) is the successor to the 3UB12 (double Slot 928B). The direct DB-RAM loading (via setting of BS144 to 1) is possible as of theend number 3UB12, which- as far as I'm concerned - means your 3UB21 supports this. Even if it wouldn't, you could still "move" all your DB's into the DB RAM via usage of OB254/255 and free up the "normal" RAM. I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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9/4/2009 5:41 PM	Rate (0)
rherrero Posts: 26 Rating: (1)	Thanks Fritz, I keep working on it as the attempt of changing the cpu failed and didn't have time to find out why because production had to start. I didn´t try OB254/255 on line but, what I understand is that I must call them in the OB1 but, i've checked in the OB's list and it doesn't show any OB254/255... Should they be there?
rherrero Posts: 26 Rating: (1)
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