At the hardware level, one faulty BLC can potentially paralyze the whole I2C bus, thus, making the 7 remaining BLCs inoperable.

There is a board splitting the I2C signal in a star of 8 I2C independant llines to each BLC.
The chip auto detects I2C signal anomalies on BLC side, and switch it off, removing it from the I2C bus.
Simple. clever.

externer Link:


Okto I2C isolator

This looks like very cool I2C isolator , i dont understand why there is not many responses to this .
Like side observation i think you should build a whole distribution board that integrate your isolators making it a
drop in replacement to the current distribution board .

I dont understand why this optos are not included on the BLS pcbs directly .

good work !!!

WOW! This is perfect! My okto crashed badly due to a failed BL_Ctrl (ESC). I was under the impression that a Okto could handle a failure, but its actually worse. A okto is like a 8 engined airplane, if one engine fails, they all do and we crash.

Holger, have you tested this? Could it be implemented in the design?

Eivind

Will the MK Software handle a missing BL_Ctrl?

Have anyone tested this?

From an hardware point of view, if a BLC electrically put the I2C down, the entire bus is down, and no software can fix the faulty bus.

Greetings,

The software is an important consideration, because it currently will not allow you to throttle up the motors if you have an I2C error. Fortunately, the software allows the motors to continue working if an I2C error occurs in flight.

Here's a link to a demo-
http://www.rcgroups.com/forums/showpost.php?p=16082549&postcount=15754

As for the distribution board suggestion, I'm not a fan of the distribution boards at all, so I won't be making one. I think the controllers should be out on the arms where they get some airflow, and anything you can do to move the high current flow items away from the electronics is helpful. Mounting all that stuff in the center section of the frame just seems wrong to me. Just my opinion of course :-)

Cheers,
Rusty

Then if a distribution board is an issue this should be integrated in the BL it self , is there any reason not to do so ?

regards

what is the differnce between your isolator and this one :
http://batchpcb.com/index.php/Products/42084

except the packaging
regards

Of course, if a faulty BLC is put off the I2C bus, the FC not seeing 8 BLCs but 7 working BLCs, won't accept to throttle them up?
When the faulty BLC is disconnected by the switch, there is no more I2C error.

In this context, of course the Sw matters.

BLC failure simulation facts & video:
http://www.rcgroups.com/forums/showpost.php?p=15677722&postcount=14321

The product you show: same principle, one per BLC, different IC.

klochto meinte

Then if a distribution board is an issue this should be integrated in the BL it self , is there any reason not to do so ?

regards

Yes, of course it "should" be on the BL-Ctrl, but the people who make those decisions apparently don't think so. I was actually pretty annoyed that they didn't put a simple opto-isolator on the new controller, since it would protect the bus from power failures on the BL-Ctrl.

If there was an opto-isolator on the controller, and a setting in software to determine what to do if a controller came up missing, that would be a pretty nice feature. For example, on a quad, you don't want the other motors to keep running, because it's going to crash anyway, and that will likely blow the controllers unless you get the motors shut down before it hits the ground (or if you have fuses). For an octo, you would want the others to keep running, and probably for a hexa as well, though they typically don't have full redundancy.

As for the other isolator design, he's using a different chip, which I tested and didn't like. Of course it's also quite different in form factor, which could be better or worse depending on your point of view.

Rusty

Hi coptaire,

here is my solution

http://www.fc00.de/i2c.htm

best regards Specky

Hello.

Where can we buy the pca9510A?

Regards.

Hi ChickenRun,

please look here

http://de.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=pca9510A&x=0&y=0

Best Regards

Specky

Hooooo Specky,

For display you said? Rusty saved a sample...
... And it is so simple!

If you need a finished product, visit this:
http://www.andyman.org/i2cbuffer/

And the PCB of course:
http://batchpcb.com/index.php/Products/42084

Now, Specky, you could compare the reliability of PCA9510A and 4304, and choose/counsel the best/secure option.

BTW, It is a pleasure to read more and more german kopterists contributing more and more in this area!

Hi,

the smaller prototype with 0603 components is completed, this time I added a size comparison



Specky

Hi,

i am ready

http://www.fc00.de/i2c.htm



Specky

Why not buy some complete ones: http://aglhobbiesllc.com/shop/viewitem.php?groupid=0&productid=32

It's way harder to integrate as I see it