Saving values in PLC code

2020-02-27T16:12:34.161000Z

Hi,

But why the retain and persistant variable are reset when I download a program with a little difference?
this should not happen, see the table from the online help!
BR
Edwin

Saving values in PLC code

2020-02-27T16:12:33.359000Z

Hi SimonD,

Alternatively you could use the SysFile library to read and write values to text files on a specified location on the raspberry. I think there is an example in the Store that will demonstrate on how to achieve this.

Regard,

Johan

Saving values in PLC code

2020-02-27T16:12:31.073000Z

OK Edwin you are right.

But why the retain and persistant variable are reset when I download a program with a little difference?

Saving values in PLC code

2020-02-27T16:12:30.243000Z

...except you are using an UPS, which make a graceful shutdown on Linux OS.
Then the Retains / Retains persistent data are saved and restored on the next Startup.
BR
Edwin

Saving values in PLC code

2020-02-27T16:12:27.948000Z

If I understand well, there is no chance to have retain variable with raspberry:

http://forum.codesys.com/viewtopic.php?f=21&t=5722&hilit=retain

Saving values in PLC code

2020-02-27T16:12:27.120000Z

Originally created by: scott_cunningham

CoDeSys provides a "GVL_PERSISTENT" object. If the Raspberry Pi supports it (it should), you simply have to create a GVL_PERSISTENT object and define your variables you wish to keep even after a power cycle.

Saving values in PLC code

2020-02-27T16:12:26.310000Z

Hi Folks, how can I save values so that they are loaded when the Pi boots up? I need to adjust values for timers during commissioning and have them saved for future use. I know I fan populate the prepared values of the tag but can I write to that register in run time?

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