SD vs SDHC

[VikingGnome]

Having trouble finding out what SD card to buy to replace my ResMed SD card. An old standard SD card stores a maximum of 2GB. The SDHC allows 4GB up to 64GB (maybe 128GB). Researching SD cards, the newer formats are not compatible with devices that use the older format. My original ResMed SD card I think is 2GB stardard card. A standard 2GB card is not easy to find locally as they are rarely used on other devices due to limited storage. A 4GB SDHC will probably NOT work in my ResMed S9 VPAP if it uses standard SD Format. Has anyone replaced their original SD card? Did a memory card storing MORE THAN 2 GB work on your ResMed S9?

[SGearhart]

A 4Gb SDHC card is probably going to be the smallest you can currently find. They will work in the S9 but will only use 2GB. I understand that the older S9's might have a problem, but the worst thing that can happen is your S9 just won't read it. No damage will occur to either device.

[JDS74]

When I last researched this issue last September, these were sources.

SD card Sources

http://www.amazon.com/SanDisk-Class-Fla ... B0009RGLSE

http://www.officesupplyinc.com/secure-d ... 7AodggcA1Q

Don't know if they are still current.

I searched for 2GD SD cards.

[palerider]

Having trouble finding out what SD card to buy to replace my ResMed SD card. An old standard SD card stores a maximum of 2GB. The SDHC allows 4GB up to 64GB (maybe 128GB).

you need sdxc to go over 32g.

as has been covered many times here in the forum, it doesn't matter what card you stick in the machine.

I've tried 2, 4, 16, 32 and 64 gig cards in mine and they all work fine, though it took a while for the 64gig to format, and it only allowed 50 gig.

so get what's cheap.

[archangle]

If you have a digital camera, see if it has an SDHC card and try it. Maybe ask a friend to borrow one.

SDHC cards are getting pretty common and inexpensive these days. You might just buy one and try it. I've even seen them in Walgreen's but they're a little pricier there.

There have been a few people who reported that SDHC doesn't work for them, but most people seem to succeed.

Here's what ResMed has to say on the issue.

Q. Why do you recommend using only ResMed-supplied SD cards?

A. ResMed-supplied SD cards should be used in order to meet safety standards (e.g., IEC 60601-1). The electrical safety test authority has determined that S9 therapy devices that use SD cards need to have appropriate clearance from the accessible part of the card to the electronic parts inside the card. ResMed has selected several SD cards that meet the necessary safety requirement and supplies these with the therapy device or as accessories. Not all SD cards on the market meet the clearance requirement or have been tested and validated to work with S9 devices.

[TexasTom]

Q. Why do you recommend using only ResMed-supplied SD cards?

A. ResMed-supplied SD cards should be used in order to meet safety standards (e.g., IEC 60601-1). The electrical safety test authority has determined that S9 therapy devices that use SD cards need to have appropriate clearance from the accessible part of the card to the electronic parts inside the card. ResMed has selected several SD cards that meet the necessary safety requirement and supplies these with the therapy device or as accessories. Not all SD cards on the market meet the clearance requirement or have been tested and validated to work with S9 devices.

This is a CYA on the part of ResMed.

As memory cards get bigger, it takes longer to access. So a valid card may "time out" responding to the processor. Both are functional, but
2G was huge when the machine was built. 32G may work, 64G may work... but "may work" is not acceptable for medical devices. Some unknown brands may run too slow, and cause a timeout (32G tested fine, but brand X 8G timed out).

Buy a name brand from Amazon. San Disk, PNY, Transcend, Kingston are just a few brand names. Just bought San Disk 16G Ulta for $12.00 from Amazon. Amazing price for what you get.

Catch is on eBay I've seen those same "brands" that failed. They are counterfeit. It is a huge problem for electronics industry and consumers. For someone like ResMed they need to buy and test the cards to insure it's compliant. Some counterfeits maybe a 1G card with a 8G label, others are unknown manufactures they may only function for a few hundred cycles, and quit.

One customer I was working with complained they were only getting a few 1000 cycles. We got their equipment, and actual measured how many times it was accessed. We gave up after seeing the card read/write had exceeded 500,000 cycles. Another time we had a name brand SD Card, but it was intermittent operation. It was a counterfeit, but had the QA lab examine the IC used.

With Sleepy Head, if you do a weekly data dump you have your data. If you buy a new SD Card, check it the next morning to see if data is present.

[OkyDoky]

TexasTom,
I was planning on buying one of these on Ebay as a backup. Are you saying it is a good chance they are counterfeit? http://www.ebay.com/itm/1-Philips-Respi ... 3f47f0dff8

[archangle]

[quote="TexasTom"]This is a CYA on the part of ResMed.

I suspect it's an actual legal requirement for them to say that. Or at least a reasonable interpretation of some government regulations.

There are requirements on mechanical spacing between the human being's body and live electrical circuits. In particular, there's a requirement for x mm spacing between a live electrical circuit and the finger of someone removing the SD card. It's entirely possible that there may be a "live" electrical contact within an SD card and someone touching the card to eject it from the machine.

The electrical circuitry inside the machine is probably low enough that there is very little actual risk even if you did touch a live circuit. Plus the air gap, even in a "bad" SD card is probably way above the level needed for actual circuitry. There's some theoretical risk that the power supply could fail and apply AC line voltage to the machine circuitry, but even then, the air gap is probably enough. Then there are considerations about what happens if there's something like a nearby lightning strike, etc.

Such a combination of failures is probably really, REALLY unlikely, but the standards specify certain levels of protection for each stage in the process and don't necessarily worry about how unlikely everything is to fail in the right way at the same time.

I've worked with such safety regulation in the past, and the regulating agencies, especially the European ones, are freaking nutz!!! Then throw in extra requirements because it's medical equipment.

[TexasTom]

TexasTom,
I was planning on buying one of these on Ebay as a backup. Are you saying it is a good chance they are counterfeit? http://www.ebay.com/itm/1-Philips-Respi ... 3f47f0dff8

That looks like a real McCoy. The laser writing on the back appears valid for a ATP Industrial Memory Card. Most likely someone bought out surplus stock and is selling it for $4.98 each. Counterfeits usually just stick a fake label on the card, and no laser etching.

You can still buy ATP 1G memory cards from Digikey. $21.60
http://www.digikey.com/product-search/E ... endor=1282

Industrial Memory is rated at -40C to +85C temperature range. Commercial memory is 0C to 70C. I really hope no one has to run their CPAP at those temperatures, but it is common to see all industrial electronic components used in medical field (i.e was on a loading dock, and rolled into the hospital and plugged in).