https://forge.codesys.com/forge/talk/Engineering/thread/05fa655d71/2025-05-19T05:26:52.340000ZRecent posts to Retain / Persistent Variables in Codesys for Raspberry Pi2025-05-19T05:26:52.340000Z2025-05-19T05:26:52.340000Zkut69https://forge.codesys.com/u/kut69/https://forge.codesys.comb68cc6ece2239af4ef3b4302a2e4a9404bd84427

<div class="markdown_content"><p>Hi,<br/> I am interested in details about the .ret file in the filesystem. I have already a project where the file is used (write on demand, read by start) and I want to share it as 'default input' for test devices using the identical application.<br/> Opening the .ret file content in a hex editor (I only use a single string retain var) I asked myself what the meaning of the first 24 bytes is. It neither contains a handle to the application nor a reference to the variable. Is this maybe a timestamp? Or a CRC/checksum?</p> <p>Regards, Thomas</p></div>

2024-08-31T19:26:36.739000Z2024-08-31T19:26:36.739000Zpietrobalinthttps://forge.codesys.com/u/pietrobalint/https://forge.codesys.comb4526796029814e1a1a2b1f334fbf091eb37b09a

<div class="markdown_content"><p>I created global persistent variables, and select "Update boot aplication" on download window and it seems to me that it works well. I replug the Raspberry Pi 5 power supply and the values holds they previous value. So I think no additional code needed. The solution is so simply. </p></div>

2024-08-31T09:47:24.348000Z2024-08-31T09:47:24.348000Zpietrobalinthttps://forge.codesys.com/u/pietrobalint/https://forge.codesys.com4a088f804146ff78b71f7c618a4f8e7f89e17158

<div class="markdown_content"><p>I made hardware reboot and it still not working. <br/> I also tried Persistence Manager which need Application Composer Single License but Codesys support said that my runtime do not compatibile with it and it will avaiable in 2025 only. So I hope I will figured out how to use this code.</p></div>

2024-08-20T07:43:49.022000Z2024-08-20T07:43:49.022000Zpietrobalinthttps://forge.codesys.com/u/pietrobalint/https://forge.codesys.com70b0bece0789f221a8b233175e1cc6fb47112935

<div class="markdown_content"><p>Hi micik,</p> <p>I am not sure I am using well the code, because I checked the directory and there is no retains.ret file.<br/> Now I deleted the code from my project and the values are still works as persistant variables after ssh reboot it seems to me they retain as their previous value. So I am a bit confused, maybe 4.12.0.0 Raspberry Pi SL solved the persitent variable problem...</p></div>

2024-08-20T05:13:55.781000Z2024-08-20T05:13:55.781000Zmicikhttps://forge.codesys.com/u/micik/https://forge.codesys.comb982fea890c1234b19f92048c30e3065f1401eec

<div class="markdown_content"><p>Hello pietrobalint,<br/> could you please how exactly you call this program? if not in the main task? Caould you please share a screenshot of how exactly you made it work?<br/> Thank you!</p></div>

2024-08-17T23:47:13.646000Z2024-08-17T23:47:13.646000Zpietrobalinthttps://forge.codesys.com/u/pietrobalint/https://forge.codesys.com6447cf6ab9731e5a672d51efe581239f9767a0c9

<div class="markdown_content"><p>Ok, I figured out that I do not call the program in the main task. <br/> Thank you for the source code, it works!</p></div>

2024-08-17T23:00:49.445000Z2024-08-17T23:00:49.445000Zpietrobalinthttps://forge.codesys.com/u/pietrobalint/https://forge.codesys.comc5c6aa1017af6d7d457e3b345c0890a7dbbeb44c

<div class="markdown_content"><p>Hi,</p> <p>I am very new in Codesys so let me apologize for my dumb question.<br/> Could you explain how to impement this code mentioned before?</p> <p>Thank you very much!</p></div>

2022-05-09T06:20:13.082000Z2022-05-09T06:20:13.082000Zprincessdvlkhttps://forge.codesys.com/u/princessdvlk/https://forge.codesys.com31c09be1d27a2a7dae50de5b511621cd6dfb9455

<div class="markdown_content"><p>Hi,<br/> definitely. I will check it out.</p></div>

2022-04-14T12:37:45.688000Z2022-04-14T12:37:45.688000Zpaulpotathttps://forge.codesys.com/u/paulpotat/https://forge.codesys.com281ba150fe3393c08901ff0e7c837ec53cea6eed

<div class="markdown_content"><p>I'm glad it helped ! <br/> Also you should check out this <a class="" href="https://forge.codesys.com/forge/talk/Engineering/thread/e837426615/">post</a>, there are other (maybe better) solutions for managing persistant variables :)</p></div>

2022-04-14T10:50:03.853000Z2022-04-14T10:50:03.853000Zprincessdvlkhttps://forge.codesys.com/u/princessdvlk/https://forge.codesys.comda54bfbd92f210cf25a67e5c55fcfe74e21d6681

<div class="markdown_content"><p>Hi, <br/> I tried your code and oh my god, you were right! It worked. YAY!<br/> I am so glad it worked because I was trying hard for the past 4 days but nothing clicked. <br/> However, I observed that to retain the changed values, the raspberry has to be shutdown properly instead of direct plug off. I mean when I directly turned off the supply and switched it back on, the pi showed me the previous values but not the changed ones. So, I shut it down properly and it worked!!<br/> Thank you so much for sharing this critical piece of information and helping me out. </p></div>