Power supplies

The EtherTen combines an Uno-equivalent Arduino-compatible board and Wiznet-based Ethernet support, along with a microSD card slot and Power-over-Ethernet support. [Product page]
Stylmast
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Power supplies

Post by Stylmast » Mon Dec 08, 2014 6:00 am

I'm after some info reguarding the power supplied to the ten.
Info (First up I smoked a eleven with jack power & usb both connected.)
Is it possible to have jack power and the usb connected at the same time?
Usb for serial monitor for fault finding, as I expand out my code for my UPS monitoring I will require power to stay on as it will be required for the calculation of battery capacity ( currently 600Ah ). If turn the power off I believe this will alter the calc for Ah left in my bank. ( code not done yet ). I'm guessing at this moment in time.

Later on I will be switching to POE, will this also create the same problem when I plug in usb of fault finding? Or is there a way to get serial monitoring over ethernet?

UPS - Currently 12Vdc, Battery charger 30A, 1Kw inverter, will also be adding solar & wind systems as money allows. Running computer system in house being used for HA & my main desktop for now. This is a test rig for now. Will upgrade to 24 Vdc at some time, after I get the monitoring side sorted out & money allows..

angusgr
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Re: Power supplies

Post by angusgr » Tue Dec 09, 2014 3:29 am

Hi Stylmast,

Yes, this is possible. The EtherTen will automatically draw power from VIn if a voltage is present, or from the USB if it is not. As long as the VIn voltage is high enough (12V is more than enough) you should find almost all of the current drawn from VIn, not from USB.

The same goes for POE, as the POE regulator output feeds into the VIn pin.

The only thing to keep in mind is that the grounds are common, so the VIn ground and the USB ground are the same. This is usually not a problem but it's worth keeping in mind (for example in cases where the computer is grounded but the other power supply is not, connecting the USB cable will ground the entire assembly to the computer).

Good luck with your project, sounds very interesting!

Angus

Stylmast
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Re: Power supplies

Post by Stylmast » Tue Dec 09, 2014 4:42 am

Hi Angus,

I have the jack being supplied via a regulated supply which I have set at 9 volts, this is getting it's supply from the UPS system.

I just didn't want to smoke up the ether 10. Be careful.

angusgr
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Re: Power supplies

Post by angusgr » Tue Dec 09, 2014 8:40 pm

Hi Scott,
Stylmast wrote: I just didn't want to smoke up the ether 10. Be careful.
No problems with being cautious, happy to try and help explain where we can!
Stylmast wrote:(First up I smoked a eleven with jack power & usb both connected.)
Sorry I somehow missed this when I first read your post. The Eleven shouldn't be damaged by this by itself, it has the same circuit to automatically select the power input based on the DC Jack ("Vin") voltage. 9V will be enough.

If it smoked up then perhaps it was the unequal grounding problem I mentioned above? If the grounds were at different potentials then joining them can induce a sudden spilke as the two equalise.

If there's anything else you can tell us about the setup when it went "bang", we might be able to help pin down a cause.


Angus

Stylmast
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Re: Power supplies

Post by Stylmast » Wed Dec 10, 2014 12:34 am

Hi Angus,

I was using the jack feed from the UPS system & the usb on the laptop, so there is always going to be a grounding problem then. Laptop was being feed from house power & not ups. I want to keep the DC side of the ups above ground less chance of noise. ( Not I'm an Electrician with over 20 yrs marine experience, DC is second nature to me. )

Maybe I will have to find a way to put a circuit in the middle of the usb lead and connect it to the ups neg rail to tie the two together. Your thoughts?

Scott

angusgr
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Re: Power supplies

Post by angusgr » Wed Dec 10, 2014 4:21 am

Hi Scott,

What you mentioned might work, I'm afraid you'll be a lot more familiar with the details of the setup and the potential problems than I am.

If there's nothing holding the UPS side above ground then might having a grounding strap you connect while debugging, before the USB cable, and then disconnect after debugging is complete possibly work?

Another suggestion, is it is possible to run the laptop from its battery while you do your testing?

Finally, you can also buy isolated USB hubs - ie http://www.amazon.com/BOSHIKA-BS-USB4-P ... 00C7I8NOI/ - they're just not particularly cheap.

Hope some of that is of some help.


Angus

Stylmast
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Re: Power supplies

Post by Stylmast » Sat Feb 14, 2015 5:49 am

I was starting to do some home work on the POE, I notice that you have removed the 48 V POE reg from your site. Does this mean they are no longer a happening device?

Scott

angusgr
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Re: Power supplies

Post by angusgr » Wed Feb 18, 2015 6:08 am

Hi Scott,

The only 48V PoE regulator we have is our 802.3af one:
http://www.freetronics.com/products/pow ... tor-8023af

This is a fully isolated 802.3af regulator, but it does require a proper 802.3af PoE switch port (or injector) in order to functon. (The older revision of this regulaor is non-isolated, the picture on the site shows the newer revision.)

If you want to do the simple/hacky PoE equivalent, and just inject DC into a CAT5 pair rather than take on the full 802.3af, then we have our 28V regulator:
http://www.freetronics.com.au/products/ ... ulator-28v

(The 28V regulator isn't isolated, so in an environment where you're worried about ground loops it's best to feed it from an isolated plug pack.)


Angus

[EDIT: Updated description of picture.]

Stylmast
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Re: Power supplies

Post by Stylmast » Wed Feb 18, 2015 7:19 am

Thanks,

Has this just been added to your site. I did a search just before my last post & didn't see any 48 V units. The 1 I have is the old style with the yellow bottom board & blue top one.

Regards

Scott

angusgr
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Re: Power supplies

Post by angusgr » Wed Feb 18, 2015 10:25 pm

Hi Scott,

The 802.3af regulator isn't new, no. We don't advertise it as "48V" because it really only works with approved 802.3af ports (there's a communication/negotiation step that has to happen before the regulator turns on.) The voltage does happen to be 48V, but just injecting plain 48V into it won't work. Does that make sense?

In terms of what regulators we sell, or have sold in the past: As far as I know, that's all the PoE-style regulators we've ever sold. Does that match the one you have, or maybe you have an image you could post?


Angus

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