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DB Value Resetting and prevention

Created by: vipz at: 6/1/2016 8:06 PM (3 Replies)

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6/1/2016 8:06 PM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Hello, I am having doubt on how DB value will behave for following situation. DB values contain setpoint which is given from HMI. Initial value of DB is 0. 1. If am making download of this DB again to CPU, actual value of DB will get reset to 0. Tested with CPU, observed the same. 2. In above conditions, after giving setpoint making upload of the project. So in uploaded project am able to see actual and initial value in offline project also. If am downloading this uploaded project again to CPU , dB actual value changes to as per the actual value of uploaded project. Not to the initial value of the dB. Tested and found above observation. Is it so ?
	Last edited by: vipz at: 6/1/2016 8:08:23 PM With Best Regards VIPZ
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6/1/2016 8:56 PM	Rate (2)
MicroMan Platinum Member Joined: 11/29/2011 Last visit: 10/24/2024 Posts: 1360 Rating: (232)	Hello, See the What does the terms Initial value (declaration view), Initial value (load memory) and Actual value mean in data blocks when a controller is loaded / restarted? articel Also see the What is the significance of the initial and actual values of a data block? I hope I could help.
	- What you read here, please check with manuals and your requirements. - Do not forget to Test, Test and Test... - If the post is helpful, please RATE it! MicroMan
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This contribution was helpful to 3 thankful Users mindware hdhosseini vipz

6/1/2016 10:54 PM	Rate (3)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Hello, Your observations make sense in this manner that: While creating a DB with only one INT cell , it occupies more memories both on load and work section of CPU's memory.It means besides the header information some additional values are stored for other tasks. When Downloading the original offline project for the 1st time, possibly zero actual values are in effect.You can initialize the actual values from Edit menu.You can simply copy the online DBs into your offline project to keep the right actual values for future downloads. Uploaded version contains the correct actual values that can be downloaded and they are in effect after download. It is possible to equalize the the actual --> initial values in STEP 7. In this manner actual values are transferred to initial values for future use (if machine setpoints and constants are final).Read more here . I hope this helps, HD Hosseini
	Last edited by: hdhosseini at: 6/1/2016 10:56:12 PM Last edited by: hdhosseini at: 6/1/2016 11:42:41 PM Demo Channel on Youtube
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This contribution was helpful to 4 thankful Users zzVss MicroMan vipz Pepsi Cola

6/2/2016 10:01 AM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Dear MicroMan,Hosseini, Thank you for the details and link.. So I got the procedure to keep DB set point values as back up.. So even uploaded backup also will do the same , right ? as i mentioned in the first post- point 2..
	With Best Regards VIPZ
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This contribution was helpful to 1 thankful Users MicroMan

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