SD Card

[Syed_Uni]

I am trying to store pressure values (MI) into a excel file using SD card functions (i.e. create SD card delimited line and Write delimited line). The values are recorded successfully into the SD card in an excel file. The issue is after I delete the old data and put the SD card back in to record the values again, I don't see any values in the excel file. 

Am I missing anything, do I avoid deleting the data? 

Thanks   

[Ausman]

I'm a bit confused by your statement that essentially says "I've deleted stuff from the card and now the data isn't there any more!"

However, change the way you're getting stuff off the card.  It sounds like you are constantly physically  removing/replacing it.  Use SD Card Explorer to do all your manipulations, this lets you do so with the card in place, without needing to be anywhere near the PLC if set up correctly.

cheers, Aus

[Syed_Uni]

Thank you for your reply. By deleting stuff from the card, I mean the data that I have saved in the excel spreadsheet in the SD card. I remove the SD card and plug it into my laptop and make a backup of the values recorded. then I delete the data present in the excel spreadsheet, close it and insert the SD card back into the controller. when I do that, it does not record values anymore. I have to format the SD card again using SD card suite and insert it back in for it to start recording values. 

Additionally, this panel is shipped to the customer and he does not want to go through the trouble of using SD card suite. Its easy for the operator to remove SD card, create a back up by copying data from spreadsheet and inserting the card back in again.

BR

Syed

 

[Ausman]

Perhaps the problem here is that the plc doesn't know where it's meant to be storing things after you've done deletions using the laptop, and thus the saving falls over. It is also possible that you are referencing the save using a counter that needs to be reset.

I would suggest that you first try doing the final deletion as a complete file delete and see what happens.  If this isn't successful then I would then try only doing the deletions using the plc itself, using some coding to do so.

cheers, Aus

[AlexUT]

12 hours ago, Syed_Uni said:

I delete the data present in the excel spreadsheet

Problem may be here - if data deleted from file, but an empty file updated on SD.

This file may be stored in Excel format, but original format is COMA DELIMITED ASCII.

This is why file cannot be modified by PLC.

Right way to eject card from PLC:

1. Stop any SD card activity at PLC - do not store data to Micro SD when you prepare to eject it.

2. Use Ladder code to unmount Micro SD card, and only then physically eject Micro SD from PLC.

*Inserting Micro SD back to PLC does not require any additional operation.

*As you stopped storing data to Micro SD before ejecting it, you have to allow storing data to Micro SD again.

Right way to transfer file from Micro SD card to PC:

1. Insert Micro SD to PC.

2. Move required file to PC, so this file will be no more presented on Micro SD.

3. Close File Explorer window with Micro SD card content or change view to outside of Micro SD card.

4. Eject Micro SD card by use of System Try Icon.

5. Physically eject Micro SD card from PC and move it to PLC.

 

You can find SD card eject details in VisiLogic Help.

 

 

 

[Flex727]

5 hours ago, AlexUT said:

This file may be stored in Excel format, but original format is COMA DELIMITED ASCII.

This is why file cannot be modified by PLC.

Almost certainly this is the problem. Did you try deleting the data in a text file editor (e.g. Notepad) instead of Excel?