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[Equipment] Inside View of a ResMed S9 CPAP Machine
#21
RE: Inside View of a ResMed S9 CPAP Machine
(01-22-2013, 12:05 AM)2Tim215 Wrote: I was wondering about the Crystal next to the bottom of the SD Card Slot. I was thinking possibly to assist the Modems they put on them for compliance?

It's close to the processor. It's probably just part of the oscillator for the processor and/or the real time clock.

I'm wondering what the gray square thing labeled 173-086 1026 is. Do you have any impressions of what it was kbeckman?
Get the free OSCAR CPAP software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
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#22
RE: Inside View of a ResMed S9 CPAP Machine
I would have thought that the battery would be solely for the real time clock. I assume the settings would be stored in flash memory on board the CPU, no need for CMOS memory then.
I guess that crystal would probably be the oscillator for the CPU. Looks like a RTC is built into the CPU as well.
I found what I think is the datasheet for the CPU but the system won't let me post links yet.
It's too hard to tell what the other chips are as the resolution of the photo isn't that good, be interesting to find out.

I have no idea what the gray square thing is either...
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#23
RE: Inside View of a ResMed S9 CPAP Machine
(01-24-2013, 10:36 AM)jeno Wrote: I would have thought that the battery would be solely for the real time clock. I assume the settings would be stored in flash memory on board the CPU, no need for CMOS memory then.
I guess that crystal would probably be the oscillator for the CPU. Looks like a RTC is built into the CPU as well.
I found what I think is the datasheet for the CPU but the system won't let me post links yet.
It's too hard to tell what the other chips are as the resolution of the photo isn't that good, be interesting to find out.

I have no idea what the gray square thing is either...

The full model of the CPU is: STM32F103ZET6
(A simple google search should get you the datasheet.)
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#24
RE: Observations and Questions.
(01-24-2013, 05:24 AM)archangle Wrote: Parts on the board as best as I can figure

Underside view

Power connector (Upper left with red, white, black wires.)
Modem connector (blue)
2 point airflow sensor (black, just below modem connector) Rests on top of two round silicone bumps. Note that the airflow sensor appears to be before the fan in the airflow path.
Main processor. (Black square just right and below 2 point airflow sensor) ARM processor.
SD card holder (Upper right)
Humidifier connector (Left edge, below power connector)
"Sensor 1" (lower left with round silicone air connector) Probably the pressure sensor located after the fan in the airflow.
SK3 (White rectangle to the left of Sensor 1) The connector where the blower plugs into the circuit board (I think).

It's neat how the only thing to plug in is the power connector for the blower motor. The airflow connectors just lay on top of the port they need. The buttons just sit on top of the switches.

How does the knob come off?

On the "Circuit Board Inside" view: (bottom PCB)
I believe Sensor 1 is likely a I2C or SPI temperature sensor. (See the RT1 going off to the left of it.) I'm not sure why the Sensor 1 chip itself has some white "O" thing on top of it. This might just be an overpressure cap that will blow out. (Instead of the patient's lungs.) I don't think it has anything to do with the chip itself.
U3 (below the two port pressure sensor) is likely some sort of op-amp.

On the "Inside Top" view: (top PCB)
The upper left 14 pin connector is likely a JTAG port for programming. (Its a 2x7 connector.)

Something else that surprised me is the large number of (probably) FETs on both sides of the board. (3 on top, 5 on bottom) These are in the (maybe?) SOT-428 packages. I think these may be either redundant (for medical device reasons) or in parallel (for larger current spike handling reasons). They are probably only handling the motor itself and the H5i would have its own control devices. (Until we see a teardown of the H5i, this is just a guess.)

One final thing: Why is this picture so low res? :-(
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#25
RE: Observations and Questions.
(02-05-2013, 12:30 PM)cpapaspiring Wrote: I believe Sensor 1 is likely a I2C or SPI temperature sensor. (See the RT1 going off to the left of it.) I'm not sure why the Sensor 1 chip itself has some white "O" thing on top of it.

That looks like the seal that connects Sensor1 to the air duct coming out of the fan. There's a hard plastic nipple sticking up from the plastic housing for the blower. That part gives a seal to connect to the airflow without leaking.

It sort of has to be a pressure sensor. The only other connection to the airflow is between the fan and the air inlet. This is the only point to sense the output pressure.

What kind of component do you think RT1 is?

(02-05-2013, 12:30 PM)cpapaspiring Wrote: Something else that surprised me is the large number of (probably) FETs on both sides of the board. (3 on top, 5 on bottom) These are in the (maybe?) SOT-428 packages. I think these may be either redundant (for medical device reasons) or in parallel (for larger current spike handling reasons). They are probably only handling the motor itself and the H5i would have its own control devices. (Until we see a teardown of the H5i, this is just a guess.)

There are 2 groups of 3 transistors near the motor connector. That's probably just the power transistors for a 3 phase DC motor controller. 2 transistors per phase.

I have no immediate guesses what the other two big transistor looking things are. They are near the motor connector, so they may be some sort of voltage or current regulation for the motor control circuits.
Get the free OSCAR CPAP software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
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#26
RE: Observations and Questions.
(02-05-2013, 05:21 PM)archangle Wrote:
(02-05-2013, 12:30 PM)cpapaspiring Wrote: I believe Sensor 1 is likely a I2C or SPI temperature sensor. (See the RT1 going off to the left of it.) I'm not sure why the Sensor 1 chip itself has some white "O" thing on top of it.

That looks like the seal that connects Sensor1 to the air duct coming out of the fan. There's a hard plastic nipple sticking up from the plastic housing for the blower. That part gives a seal to connect to the airflow without leaking.

It sort of has to be a pressure sensor. The only other connection to the airflow is between the fan and the air inlet. This is the only point to sense the output pressure.

What kind of component do you think RT1 is?

(02-05-2013, 12:30 PM)cpapaspiring Wrote: Something else that surprised me is the large number of (probably) FETs on both sides of the board. (3 on top, 5 on bottom) These are in the (maybe?) SOT-428 packages. I think these may be either redundant (for medical device reasons) or in parallel (for larger current spike handling reasons). They are probably only handling the motor itself and the H5i would have its own control devices. (Until we see a teardown of the H5i, this is just a guess.)

There are 2 groups of 3 transistors near the motor connector. That's probably just the power transistors for a 3 phase DC motor controller. 2 transistors per phase.

I have no immediate guesses what the other two big transistor looking things are. They are near the motor connector, so they may be some sort of voltage or current regulation for the motor control circuits.

I was going to saying its a 3 phase DC motor as well, but then you see the motor plug is 4 wires. (Using 3 or 4 wires.) My guess is: DC motor with feedback of some kind for speed regulation. (V+, feedback, gnd) One of the Resmed brochures shows the motor opened up with 3 wires. (I wish I could paste the link...)

RT1 is probably a surface mount thermistor. (Which can come in the package that looks like a surface mount resistor.)
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#27
RE: Observations and Questions.
(02-05-2013, 12:30 PM)cpapaspiring Wrote: One final thing: Why is this picture so low res? :-(

To save server space and bandwidth.

Below are the links to the 3 original PDFs (high res) that were sent to me from kbeckman:

Bottom inside:
http://www.apneaboard.net/pics/Resmed%20...inside.pdf

Board underside:
http://www.apneaboard.net/pics/Resmed%20...erside.pdf

Top inside:
http://www.apneaboard.net/pics/Resmed%20...inside.pdf

I would only ask that you not post the links of these large files to other forums or websites... we're trying to control costs and conserve bandwidth. Thanks.


Smile
SuperSleeper
Apnea Board Administrator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.


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#28
RE: Observations and Questions.
(02-05-2013, 06:45 PM)cpapaspiring Wrote: I was going to saying its a 3 phase DC motor as well, but then you see the motor plug is 4 wires. (Using 3 or 4 wires.) My guess is: DC motor with feedback of some kind for speed regulation. (V+, feedback, gnd) One of the Resmed brochures shows the motor opened up with 3 wires. (I wish I could paste the link...)

3 or 4 wires would be right for a 3 phase DC motor.

Get the free OSCAR CPAP software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Post Reply Post Reply
#29
RE: Observations and Questions.
(02-05-2013, 06:45 PM)cpapaspiring Wrote: DC motor with feedback of some kind for speed regulation. (V+, feedback, gnd) One of the Resmed brochures shows the motor opened up with 3 wires. (I wish I could paste the link...)

The anti-link software feature is a feature to prevent spammers from joining the forum and immediately posting spam links. Once you've got a few posts and a few days as a new member, the software will automatically remove that limitation on your account.

If you'd like to post a link to a brochure, you can send me the link via email and I can post it for you here in this thread. Email: apneaboard@gmail.com

Coffee
SuperSleeper
Apnea Board Administrator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.


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#30
RE: Observations and Questions.
(02-05-2013, 06:45 PM)cpapaspiring Wrote: DC motor with feedback of some kind for speed regulation. (V+, feedback, gnd) One of the Resmed brochures shows the motor opened up with 3 wires. (I wish I could paste the link...)

cpapaspiring emailed me the link, here it is:

http://www.resmed.com/us/assets/document...er_eng.pdf

Thanks cpapaspiring!

Smile
SuperSleeper
Apnea Board Administrator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.


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