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Work memory question

Created by: jjsipazopp at: 11/18/2022 1:02 PM (1 Replies)

11/18/2022 1:02 PM	Rate (0)
jjsipazopp Member Joined: 3/2/2022 Last visit: 9/22/2023 Posts: 3 Rating: (1)	Hi, Recently I had a problem where I had to estimate the amount of work memory required for a certain project I was working on. Since I wasn't able to transfer everything on the CPU right away what I did is that I found the sum of all blocks of a program. After that when I was finally able to transfer my project on the CPU and go online, the amount of memory occupied was completely different. Offline: work memory from sum of al blocks was like 125kbytes; Online: PLC memory info of cpu, without communication with dp slaves (10 slaves exchanging small amount of data in and out), was showing 63kbytes of work memory occupied (25%). I'd like to ask how this is possible and what is actual work memory? The cpu is IM151-8F PN/DP. Thank you in advance!

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11/18/2022 2:09 PM	Rate (0)
JBS98 Regular Member Joined: 7/19/2022 Last visit: 11/11/2024 Posts: 419 Rating: (71)	Hi jjsipazopp, The working memory of your CPU depends on the exact model you have. For example IM151-8F PN/DP CPUs have 256KB of working memory (6ES7151-8FB01-0AB0) and older ones have 192KB (6ES7151-8FB00-0AB0). Another thing to keep in mind is that not all block memory goes into working memory. There are parts that go to the load memory, others to the retentive memory... Therefore, when you go online you will see that you have a lower amount of working memory than what you got by adding up what each block occupies.
	If this Information really helps, you could use the Rate function Best Regards, JBS98
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