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Biggest work memory?

Created by: Beavis at: 9/21/2010 3:52 PM (6 Replies)

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9/21/2010 3:52 PM	Rate (0)
Beavis Advanced Member Joined: 3/9/2009 Last visit: 2/5/2021 Posts: 53 Rating: (7)	Hi! I have to log a huge amount of data (from 1 to 8 MEGAbytes) using a S7-3xx CPU. I was going to use a 317-2KE14 CPU but I see that the maximum work memory is limited to 1Mb I can see other CPU (like 319-3) that can reach a work memory of 1.4Mb. Is there any way to EXPAND the work memory? or... is there any way to store a huge amount of data (few Megabytes)in a PLC? Thanks for your help Francesco.

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9/21/2010 4:37 PM	Rate (0)
miami Platinum Expert Joined: 8/31/2005 Last visit: 8/20/2024 Posts: 2198 Rating: (328)	Beavis Is there any way to EXPAND the work memory? S7-300: no Beavis is there any way to store a huge amount of data (few Megabytes)in a PLC? It is possible to store unlinked DBs in the MMC. I found this FAQwithsome informationson it. Try to look for "unlinked" and "SFC 84" in the manuals.

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9/21/2010 5:03 PM	Rate (0)
Beavis Advanced Member Joined: 3/9/2009 Last visit: 2/5/2021 Posts: 53 Rating: (7)	Thanks for the quick reply! Probably unlinked DB cannot be monitored from an external HMI.... but I will give it a try. Best Regards!

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9/21/2010 5:26 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 10/14/2024 Posts: 12287 Rating: (2685)	Hello Beavis; You do realize that using the PLC as a data collection unit, especially in the amounts you are mentionning, is not considered good practices, especially if you plan to max out your work memory. This is generally done preferably in the HMI or SCADA systems, where external memory (USB sticks, MMC, Flash cards or harddisks) can be made available for exactly this use. Have a ;look at the following sample program that will send your data from the PLCin an Excel format to either a USB stick on a TP277 or on the harddisk of a PC networked with the TP277: http://support.automation.siemens.com/WW/view/en/35929465 In my experience, the work memory of the PLC should be left to do just that: work (controlling the process, establishing comms, evaluating inputs and outputs). The design of the machine is not optimized for data acquisition. Hope this helps, Daniel Chartier
	Last edited by: dchartier at: 9/21/2010 7:46 PM
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9/22/2010 2:57 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 10/14/2024 Posts: 3024 Rating: (1054)	Beavis I can see other CPU (like 319-3) that can reach a work memory of 1.4Mb. Is there any way to EXPAND the work memory? or... is there any way to store a huge amount of data (few Megabytes)in a PLC? Hello Beavis I fully agree with Daniel's comments, but if you really MUST have an S7 PLC which is able to store up to 8 MByte of datain its memory you do have a couple of options: 1.) Spend some real money and buy an S7 417CPU, the 6ES7417-4XL04-0Awill give you 10MByte of DB memory (see HERE for technical spec). 2.) If that's not enough, you can opt for a WINAC Soft PLC. The WINAC RTX 2009(see HERE for tecnical spec) theoretically supports 4GByte of DB memory (max 65535 DB's, each up to 64KByte in size in which case you would need to be able to have 4GByte of non paged memory reserved for it though). 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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9/22/2010 7:49 AM	Rate (0)
Beavis Advanced Member Joined: 3/9/2009 Last visit: 2/5/2021 Posts: 53 Rating: (7)	I fully agree that PLC is NOT designed to be a data collecting unit.... I am however try to deal with some weird customer specifications where a huge amount of data (gathered from PLC) should be stored for a few days on a DISKLESS system... In addition, data should be MONITORED on a HMI and stored there too... but has to be stored somewhere else too...

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9/22/2010 8:18 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 10/14/2024 Posts: 3024 Rating: (1054)	Beavis I am however try to deal with some weird customer specifications where a huge amount of data (gathered from PLC) should be stored for a few days on a DISKLESS system... Easy fix: Supply him with a PC that has a SSD (Solid State Drive)and your "weird" customer will have to accept it as a diskless system .
	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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