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cantcliff

Planning on testing and SD extender with V570

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I know some people have been looking for an alternate method of accessing the microSD without opening their cabinets due to environmental and/or hazard conditions.

 

Recently found this:  http://www.amazon.com/48cm-Sd-micro-Card-Extender-Cable/dp/B007WYRO7O  while researching some options.

 

Planning on picking one up and doing some testing to see if it responds without issues and doesn't affect the SD card reliability and retention.

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Initial Tests

 

Extender seems to function correctly so far, though, may vary based on micro-SD card manufacturer.  Cloned firmware without issues, applied the clone to another PLC without issue.

 

Next Step

 

Currently doing some extended testing with logging and trend charts.

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Hi Cantcliff

 

How does the PLC react to the card removal and re-insertion?

Does the PLC recognize that the card is in or has been removed from the extender?

 

Regards

 

Denis

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Very much mixed results.

 

Using SB 217, 218 to verify

 

1) If I plug in the extension, with no card, they registers 0,0

2) If I then plug in a card, they registers 1,1

3) Removing the card they stays 1,1

4) Putting the card back in writes continue as intended with 1,1

5) Removing the cable from the PLC, they return to 0,0

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All things said the card works fine in the system but removing it and re-inserting does appear to cause some problems.  I believe there is a pullup resistor, or some other mechanism for the extension cable to work correctly.

 

I'm mixed feelings on the issue.   Having the card not detect removal correctly could be problematic, but then, a power cycle corrects this issue.  However, power cycling isn't a

good option. 

 

 

Overall, it's a workable solution, but being as it was designed for car automotive use, I can see the drawbacks based on the above.

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