I recognize retentivity strangeness on brand new LOGO!8 mfg date 2016.

All LOGO! switched on first time and load its program from SD card. In SD card program is many counter which have retentivity ON and def value 0.

After first startup I see in some case (in some LOGO!) strange values (e.g. 32456) in this counters. But it is not possible because this LOGO! instance has no memory for retentive values and its default value is 0!

Anybody see this kind of strangeness before? Have idea how to workaround this problem?

This problem maybe linked to one of this problems:

To "LOGO!Soft Comfort V8, export logo to bin error", because I need transfer LOGO! to write SD card as described in this topic. And maybe SD card program contain retentive information of transfer logo too?

To "LOGO! 8 and M8 pwr reset" because maybe the value load sequence is other than described in this topic?

There can be one more cause. If retentivity used, then reset pin of retentive element must not be connected to reset (M8), because it is overwrite retentive value. But in this way new LOGO! at first time startup detect there is no retentive value, then load nothing to retentive element . Because no reset on retentive element, then its initial value not set. Therefore retentive element’s initial value is unsure. Maybe that is what we see.

Hello Kz,

I could not undestant your post.

Could you please write exactly you did and what happened? One thing for each time.

Regards,

kzsolt2

I recognize retentivity strangeness on brand new LOGO!8 mfg date 2016.

All LOGO! switched on first time and load its program from SD card. In SD card program is many counter which have retentivity ON and def value 0.

After first startup I see in some case (in some LOGO!) strange values (e.g. 32456) in this counters. But it is not possible because this LOGO! instance has no memory for retentive values and its default value is 0!

Anybody see this kind of strangeness before? Have idea how to workaround this problem?

This problem maybe linked to one of this problems:

To "LOGO!Soft Comfort V8, export logo to bin error", because I need transfer LOGO! to write SD card as described in this topic. And maybe SD card program contain retentive information of transfer logo too?

To "LOGO! 8 and M8 pwr reset" because maybe the value load sequence is other than described in this topic?

There can be one more cause. If retentivity used, then reset pin of retentive element must not be connected to reset (M8), because it is overwrite retentive value. But in this way new LOGO! at first time startup detect there is no retentive value, then load nothing to retentive element . Because no reset on retentive element, then its initial value not set. Therefore retentive element’s initial value is unsure. Maybe that is what we see.

check this

I think this article describe: there is no retentive value stored in program. 

Therefore is only one one solution: LOGO! internal microchip program (not the user program) forgot to erease internal paramter (retent) flash when new program loaded.  The result is random value in retent blocks.