"Sticky" SB217 - SD Card Present

[MikahB]

I was expecting SB 217 to Set when an SD card is inserted and to Reset if/when it is removed.  What I'm seeing, however, is that when I remove the SD card the SB does not Reset.  Is this by design or do I need to somehow initiate another "check" to see that the SD card is there?

[Flex727]

I use SB217 as the link to a Binary Text Variable on every project I write. I haven't ever seen this behavior. It should reset almost immediately when the SD card is removed. No other "check" is required.

[MikahB]

Thanks, that's exactly my setup.  It basically ruins SD functionality once it sticks "on," also.  Re-inserting does not make the card readable, etc.

 

I have tried re-formatting the (brand new) SD cards in Windows first, then with the SD Card Suite, no change.  Not really sure what to try next.

[MikahB]

Okay, think I found the culprit, it's the extension cable.  Don't know exactly why, but if I pull the extension out of the SD slot on the panel, it registers the eject and things work again.

 

I may try another extension as getting data out is critical, there is no network available, and it's not reasonable to expect the users to dismount the panel to access the SD card.

[Flex727]

I've never used an extension cable - but only because I never thought of it - it sounds like a great idea. However, looking online, I see yours is a common problem across platforms. This is likely not something within Unitronics' control. If your process can tolerate it, you might try a quick reboot of the PLC (using SB 300) when you want to replace the card.

[MikahB]

I've never used an extension cable - but only because I never thought of it - it sounds like a great idea. However, looking online, I see yours is a common problem across platforms. This is likely not something within Unitronics' control. If your process can tolerate it, you might try a quick reboot of the PLC (using SB 300) when you want to replace the card.

 

Yeah, for this application the users run the machine which generates test data, then they need to take that data with them at the end of the session/day to fiddle with in Excel.  So, having the SD card accessible was key, but you are correct that the extension cable problem has nothing to do with Unitronics software/hardware, it's related (if I understand correctly) to the standard spec on the card readers.  Apparently they want a mechanical ejection to trigger an eject event.

 

So, I instructed the users to simply restart the PLC if they need to eject and re-insert, and all seems okay now.  Maybe adding a FB to trigger this SD card eject event could be a future addition.  The extension cables really do make it nice to get an SD card accessible outside the cabinet.  In this particular case, not having the SD card capability would have meant I could not use the V1210.

[Weert-Engineering]

Hi, I came across the same problem. I am also using an extension cable.

I found that if  I use the "SD safely remove" function block, SB217 will reset when the SD card is removed from the extension cable.