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Zwave range and power

Posted: 04 Jun 2018 23:15
by coco82
Hi,

I installed a zuno. It's 15 meters far from the controller (razberry).
The communication didn't work, so I added an external antenna. Not better...

After several tries, I found out that the communication works if the zuno is powered by the USB port.

In my project, it's powered by an external AC-DC converter (5V) via the 5V pin. The communication works only if the Zuno is closer from the controller (<8m).

Is there a difference between the power supply via the USB Port and the 5V pin?

thanks for your help

Re: Zwave range and power

Posted: 04 Jun 2018 23:25
by PoltoS
There should be no difference. Make sure your AC/DC is powerful enough (sometimes people take some old 0.1 A and connect it to things like Z-Uno with many peripherals). I would suggest at least 0.5 A

Re: Zwave range and power

Posted: 05 Jun 2018 11:30
by coco82
My AC/DC can supply 1.5A.

Re: Zwave range and power

Posted: 13 Jun 2018 10:19
by schmidmi
Maybe your DC is a little bit dirty and disturbing the Z-Wave communication.
You should try a different power supply.

Re: Zwave range and power

Posted: 15 Feb 2019 18:47
by aleconakad
Hi,

I am facing the same issue here. I am using a Meanwell DIN 12V AC/DC power supply connected directly to 7-18V pin. Range is really miserable. With USB cable connected range is way better. Is there a way to control the power of the transmission of these modules. I am not sure about it but I think on Z-wave there is the CC COMMAND_CLASS_POWERLEVEL. I am not sure how to use it and if it affects the transmission in some way.

Re: Zwave range and power

Posted: 15 Feb 2019 20:56
by PoltoS
Default power level is the maximum, so you can not improve it.

We will check if we can reproduce the same issue.

Re: Zwave range and power

Posted: 26 Feb 2019 09:30
by petergebruers
Hi! I recently wrote this on the Fibaro forum. It is about the range of a UZB1 <-> Wall Plug and especially the difference in range I get depending on how I power that UZB1. It might give you an idea of where to look. I think it has to do with noise on the power supply. But I am not sure...

I am trying to help a guy with 10 - 20 nodes, mostly Qubino and Fibaro stuff. His controller is a UZB1. He gets poor performance, not many of the nodes seem to have the controller as neighbor and log files indicate RTT is sometimes as expected but often shoots up in the seconds range.

I wanted to check the range of some of my devices anyway.

Having a portable controller station (My MAC or a Lenovo laptop + UZB1) running my Python NOP test enabled me to map range and indicate weak spots. I might post some data later. (EDIT: I did, you can see the maps here: https://forum.fibaro.com/topic/42703-ge ... ent=179282 )

But then I forgot... RF is almost like voodoo... I am an engineer and I toyed with FM radio transmitters when I was young.

I might be able to explain why this users' range is not good and might be able to fix it.

I have tested the range of the UZB1 on my Macbook Pro and it is OK. It depends on the other device as well and a Wall Plug Gen1 is not as good as a Roller Shtter 3 = Z-Wave Plus.

Then I used my Lenovo Laptop, to see if the results were consistent.

Range on my Lenovo was reduced by 50 % compared with my Mac and an extension cord improved things a bit but it was still bad

My suspicion is, not only the fact that the Mac is a large slab of aluminium gives it a good range... But it might have less noisy USB ports (supply).

Then I put a small, unpowered USB hub (4-port) between UZB1 and Lenovo laptop and the result was that the range got almost as good as on my Macbook
This got me thinking... Why?

I added a function to my test-python-script to get the "Background Noise" between NOP test.

Dongle plugged directly into the laptop:
Noise: Ch0: -80 Ch1: -85
Noise: Ch0: -68 Ch1: -77
Noise: Ch0: -80 Ch1: -74
Noise: Ch0: -74 Ch1: -79

Dongle plugged into the USB hub:
Noise: Ch0: -89 Ch1: -91
Noise: Ch0: -82 Ch1: -89
Noise: Ch0: -85 Ch1: -94
Noise: Ch0: -79 Ch1: -88

Without the hub the noise is 5 to 10 dB higher, and this is what kills the range.
My theory is that the extra capacitors in the hub filter the supply voltage to the UZB1. But that is hard to prove right now.

For sake of completeness... The docs say:
The rssi level is defined as the RSSI measured at the antenna when no Z-Wave traffic is present.
The dynamic range of rssi measurements on a 500-series Z-Wave chip is from -94 dBm to -32 dBm. The
precision of the measurement is +/- 2 dBm. The returned values assume a path loss of ~7 dBm from chip
input to antenna.

To put that in perspective, where I am sitting now here is a representative NOP stat:
Status TX ms #rep RSSI ACKCha LTXCha Routing Scheme Repeaters Speed Tries Fail_from_to
OK 30 0 -88 1 1 DIRECT 0 0 0 0 40k 1 0 0

So RSSI of -88 for this node is clearly close to the background noise level of the UZB1 plugged into the hub. I am sitting at the edge of the range of my Wall Plug. If I were to plug in the UZB1 directly, the noise would overwhelm the signal and I get 0% ACK... It is still OK for my MAC (but not great and it will switch to routing mode if it gets a bit noisier).

Figures on my Mac, UZB1 plugged in directly:
Noise: Ch0: -94 Ch1: -94
Noise: Ch0: -92 Ch1: <MIN
Noise: Ch0: -94 Ch1: -94
Noise: Ch0: <MIN Ch1: <MIN

That <MIN means "lower than measurement floor" so less noise than -95 dB. A few dB better than my Lenovo I think...

Note: users of eg Z-Way can find background noise in "Expert User Interface".

forgot to test MAC + USB hub + dongle. Surprise... It makes things worse... Apparently the same hub now increase the noise floor...
Noise: Ch0: -75 Ch1: -79

Doh! Voodoo!

Re: Zwave range and power

Posted: 10 Mar 2019 12:26
by PoltoS
I would suggest just an extension cable of 10-15 cm. Your laptop is made of metal and this kills the antenna. Using the hub makes it better depending big you move UZB out of laptop or closer. This is why your tests are not so predictable.

Re: Zwave range and power

Posted: 10 Mar 2019 15:01
by petergebruers
Thank you for your reply. I understand what you are saying, but the results with short extension cable are not as good as the test with the USB hub on my Lenovo. Also, I get excellent results on my MAC when UZB1 is plugged in with no extension cord at all and the macbook is a block of aluminium I think. You say "Your laptop is made of metal and this kills the antenna" but that is not what I see, and that is why I say "RF is voodoo" :) ... The OP said "After several tries, I found out that the communication works if the zuno is powered by the USB port. In my project, it's powered by an external AC-DC converter (5V) via the 5V pin. The communication works only if the Zuno is closer from the controller (<8m).". That seems to imply that the only change is the type of power supply, and my test suggest that it might indeed be power supply related. It is complicated...

Re: Zwave range and power

Posted: 10 Mar 2019 15:19
by petergebruers
Can the Z-Uno report packet RSSI and possibly background noise RSSI? That might help to do some tests... I saw the Z-Uno debug setting has an option "Radio" but I haven't looked at it closely and I cannot test right now.