Power Meter Link (PML) smoothing results in meaningless power values

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warn
Posts: 9
Joined: Fri Mar 24, 2023 11:02 pm

Power Meter Link (PML) smoothing results in meaningless power values

Postby warn » Sat Sep 09, 2023 8:36 am

Dear Elite team,

when I use my Elite Nero with Power Meter Link (Favero Assioma pedals) I observe temporal smoothing of more than 20 seconds. This is very unsatisfying especially during virtual races. I cannot observe any smoothing of this magnitude in the (inaccurate) power values estimated directly by the Elite Nero.

Unfortunately, it seems like a smoothing parameter cannot be set for the Nero. (https://elitesrl.zendesk.com/hc/en-us/a ... -function#)
The following topics are probably related:
2769
3382
3530

Is there any way of turning of the smoothing or would this require some firmware update?

Attachments:
with Power Meter Link: Power values increase / decrease slowly after change of cadence / speed. (Resistance is constantly set to 1)
PML_smoothed.png
PML_smoothed.png (39.5 KiB) Viewed 20608 times


without Power Meter Link: Power values increase / decrease immediatly after change of cadence / speed. (Resistance is constantly set to 1)
noPML.png
noPML.png (43.51 KiB) Viewed 20608 times


Firmware:
firmware_version.png
firmware_version.png (77.05 KiB) Viewed 20608 times


Thank you and kind regards,
Christoph

User avatar
Elite Admin S
Posts: 2776
Joined: Tue Nov 08, 2016 10:18 am

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby Elite Admin S » Mon Sep 11, 2023 2:33 pm

Hi Christoph

Please disable PML and pair the external power sensor in the configuration (without using the PML)
What happens in this case?


Regards

warn
Posts: 9
Joined: Fri Mar 24, 2023 11:02 pm

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby warn » Tue Sep 12, 2023 9:19 pm

Dear Elite admin,

thank you for the quick reply.
I disabled PML and connected the power sensor via Bluetooth in the My E-Training settings.
The power values look perfectly reasonable.
Assioma_bt_connection_small.png
Assioma_bt_connection_small.png (41.88 KiB) Viewed 20558 times


I look forward to your response,
Christoph

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Elite Admin S
Posts: 2776
Joined: Tue Nov 08, 2016 10:18 am

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby Elite Admin S » Wed Sep 13, 2023 11:38 am

Thanks for the test.

A minor delay when using the PML is expected and quite typical. It's important to understand that the power sensor transmits data to the trainer, and subsequently, the trainer communicates this data to the app. Therefore, a delay of 2-3 seconds is considered within the normal range.

However, in your specific case, you mentioned experiencing delays of up to 20 seconds, which is definitely unusual. This could potentially be attributed to interference of some kind that is disrupting the transmission of data packets. It's worth noting that this interference may be occurring within the same frequency band as the ANT+ protocol, which could explain why you're not encountering the same issue when using Bluetooth.

To troubleshoot this, you might want to try disabling all wireless devices in the vicinity, including your modem, in order to pinpoint the source of the interference.

warn
Posts: 9
Joined: Fri Mar 24, 2023 11:02 pm

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby warn » Wed Sep 13, 2023 3:07 pm

Hi,
I can understand the described reasons for a delay of up to 3 seconds.

However, the power values I have shown cannot be explained by ANT+ transmission problems for two reasons:
1. I have additionally performed a test with PML over Bluetooth and observe comparable power values as before with PML over ANT+
PML_via_bt_small.png
PML_via_bt_small.png (46.85 KiB) Viewed 20538 times

power_values_PML_via_bt_small.png
power_values_PML_via_bt_small.png (38.37 KiB) Viewed 20538 times

2. I have tried to pedal power values according to a step function. This is also shown by the speed curve and cadence curve (constant resistance). According to my understanding, transmission errors would lead to a delayed step function. However, the displayed power curve shows a step response without significant delay but the power values increase/decrease slowly and continuously almost linearly up/down to the actual value. This indicates to me some filtering of the external power values is performed when using PML.

Am I right that the cadence values are not received via PML? Otherwise this would also show that there can't be transmission errors because the cadance values look reasonable.

Kind regards,
Christoph

warn
Posts: 9
Joined: Fri Mar 24, 2023 11:02 pm

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby warn » Sat Sep 23, 2023 7:40 am

Dear Elite admin,

I am very happy about your previous short response times to this topic. However, since I haven't received a response to my last post in a while, I would be very grateful if you could tell me where you see the reason for the problem or if you are already investigating it. If desired, I will gladly perform further tests.

Kind regards,
Christoph

warn
Posts: 9
Joined: Fri Mar 24, 2023 11:02 pm

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby warn » Sat Nov 04, 2023 9:37 pm

Hello,

I used the ticket system to ask if the Nero could simply transmit the power values it receives via PML to the connected smartphone. I have attached the following graphics to this ticket, which show the unusability of the Nero for virtual competitions.

Incorrect values without PML:
noPML.png
noPML.png (132.58 KiB) Viewed 16687 times


Delayed / smoothed values with PML:
PML.png
PML.png (144.61 KiB) Viewed 16687 times


Elite replied that it was not technically possible to reduce the delay when using PML. Although I asked for an explanation, I was not given one.

TobiasHermann
Posts: 1
Joined: Thu Jan 18, 2024 7:59 am

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby TobiasHermann » Sat Jan 20, 2024 2:44 pm

Hi, I know it's an old thread, but I'm having the same problem.

As an example, 30-second intervals look like this:

Without PML:
Image

With PML:
Image

Did you find a solution?

brendan.ronayne
Posts: 2
Joined: Mon Sep 23, 2024 11:45 pm

Re: Power Meter Link (PML) smoothing results in meaningless power values

Postby brendan.ronayne » Mon Sep 23, 2024 11:48 pm

Hi

Has anyone found an answer for this yet?
The reason I bought the Nero Rollers was to use it with Zwift. With this long lag, it is virtually useless.

Is it possible to connect the power meter directly to Zwift (I'm using Apple TV) and connect the Nero for resistance?

Any help that anyone can give will be very gratefully received.

Thanks
Brendan


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