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Min/Max retentivity simulation / online test mismatch

Created by: R_Tet at: 11/20/2024 1:02 AM (12 Replies)

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11/20/2024 1:02 AM	Rate (0)
R_Tet Joined: 11/10/2024 Last visit: 11/23/2024 Posts: 9 Rating: (0)	Hi, I am working on a project where I want the user to be able to change some values from the integrated/custom logo! website. All works fine, but I would like these values to be saved in case of power off/on. I saw several posts where a Min/Max block is used with retentivity on and mode = 3. In simulation mode this works perfectly! I would have a save button on the website and that would enable the En pin of Min/Max block, and Ax would be populated by a Network Analog Input register. Works great in simulation mode, but when running in online mode the value does not go into the min/max Block. Is something wrong with my hardware? I have a LOGO!8 6ED1052-xxx08 0BA0 Attachment retentivity_issue.zip (252 Downloads)

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11/20/2024 5:24 AM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 9/6/2025 Posts: 35928 Rating: (4497)	The MAX/MIN block saves when it detects a falling edge at the EN input (mode 3, retentivity on). If there is a 1 signal at the EN input, the MAX/MIN block forwards the current analog input signal Ax to the analog output as long as the signal at the EN input remains at a 1 signal. If the signal at the EN input then changes to a 0 signal, the value of the Ax input is saved and the saved value is available at the block's analog output. Please write exactly which signal you want to save. If there is a power failure, the block is not able to initiate the save process on its own.

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11/20/2024 4:11 PM	Rate (0)
R_Tet Joined: 11/10/2024 Last visit: 11/23/2024 Posts: 9 Rating: (0)	I am trying to retain the Analog value of NetworkAnalogInput1. So the idea is, that a person would write a percentage value (0-100), in the VW0 register, then press on a button (in this case I1) that would power the En input of Min/Max block and that 0-100 value would be retained in that Min/Max block in case of power outage. When running this simulation, it works perfectly. I use the data table to write a value to VW0, then enable I1 (if it is a switch then it also needs to be turned off). That value can then be read from the Min/Max block Aq port (as seen in the picture), but when this is done in an online test. Enabling the En pin does not seem to work, as the analog value never gets into the Min/Max block Aq port. Could it be that my particular hardware has a difference in how the Min/Max block works?
	Last edited by: R_Tet at: 11/20/2024 16:12:38
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11/20/2024 4:18 PM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 9/6/2025 Posts: 35928 Rating: (4497)	Where does this value come from? From an HMI? Or from the web server? Or other?

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11/20/2024 4:30 PM	Rate (0)
R_Tet Joined: 11/10/2024 Last visit: 11/23/2024 Posts: 9 Rating: (0)	This value would come from the web server in this case, but I plan on adding an HMI in the future, does that change anything?

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11/20/2024 4:34 PM	Rate (1)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 9/6/2025 Posts: 35928 Rating: (4497)	If in the case that the value come from a HMI or the web server then is it better you write via Parameter VM Mapping directly in a parameter of a Analog MUX or a Mathematic Instruction. Which LOGO! have you? Which web server use you? Simple or the extended? I see it in the post above ...
	Last edited by: ixo65 at: 11/20/2024 16:35:54
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11/20/2024 4:38 PM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 9/6/2025 Posts: 35928 Rating: (4497)	I made you a simple example for the LOGO! 8.2 and the extended web server.

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11/20/2024 4:42 PM	Rate (0)
R_Tet Joined: 11/10/2024 Last visit: 11/23/2024 Posts: 9 Rating: (0)	Ok I could try that out, thank you very much for your help with this! I am not sure if you meant to attach the example in your previous post, as I can' t see it there.
	Last edited by: R_Tet at: 11/20/2024 16:42:55
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11/20/2024 5:06 PM	Rate (1)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 9/6/2025 Posts: 35928 Rating: (4497)	Here's the example. If you write directly in a parameter of an Analog MUX or a Mathematic Instruction then is it retentive because the value would written in a flash memory. Try it and see ... Attachment R_Tet.zip (238 Downloads)

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11/20/2024 5:22 PM	Rate (0)
R_Tet Joined: 11/10/2024 Last visit: 11/23/2024 Posts: 9 Rating: (0)	For some reason I am unable to open the lwe project, it is giving me an "Upgrade the application to open the project" Error, I have LWE 1.2.0, and going to Tools -> Update seems to indicate that there aren't any updates available. I will try re-creating it from your previous instructuions, to see if I can replicate the functionality you described. Thanks again for the quick replies!

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