Intermittent drops in cadence

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saosijs
Posts: 4
Joined: Sun May 02, 2021 2:56 pm

Intermittent drops in cadence

Post by saosijs »

Hello Forum,
with a PP BLE I see strange intermittent drops in the Cadence values.
It shows on my Garmin Edge where I noticed it first, and it also shows when opening the ride with Isaac.
See the image where the marked purple areas show the drops very clearly:
.
PP_graphs.png
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.
I hardly changed gears, there was no need except for some wind fluctuations, so Gear Ratio looks funny too.
The areas relate to an asphalted, flat, long two-way cycling path which I rode two ways (O-B).
Garmin Support suspects interference as the PP might be retransmitting Cadence. Is that possible?
I did a test without the PP started and sure enough the Garmin didn't show the drops.
Equipment: PowerPod BLE, Garmin Edge 530, Speed Sensor 2 & Cadence Sensor 2. Ride file attached.
I have tried removing the sensor batteries for 15 minutes, and hard-resetting the PP (>10 sec press).
Any ideas are much appreciated!

Unrelated, I noticed that when during a ride I turned on the PP, power didn't show up on the Garmin Edge.
Later though, I saw in Isaac that the PP itself had recorded the data. Is this expected behavior?
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lorduintah
Posts: 642
Joined: Fri Jan 11, 2008 9:37 am
Location: Plymouth, MN

Re: Intermittent drops in cadence

Post by lorduintah »

Are you waking up your sensors, then turning on the PP and finally the Garmin - or do you turn on the Garmin before the PP?? So what order do you follow - Sensors, PP, Garmin, or .......
saosijs
Posts: 4
Joined: Sun May 02, 2021 2:56 pm

Re: Intermittent drops in cadence

Post by saosijs »

For the case where during a ride I turned on the PP, this obviously was when the Garmin sensors and Edge already were turned on, even for 30 minutes (to be honest, I tried this only once). So it was like:
  • Sensors ..t1.. Garmin Edge ..t2.. PP
  • Garmin Edge ..t1.. Sensors ..t2.. PP
t1 maybe 1 or 2 minutes, t2 was 30 minutes.

Thinking about it, the ride file I posted with the intermittent cadence drops, is not that much different. I turn on the PP last, but t2 was much shorter though (like 1 minute). Anyway, the pairing seemed ok, as I saw reasonable numbers on the Edge, except for the drops, as the image shows in my first post.
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lorduintah
Posts: 642
Joined: Fri Jan 11, 2008 9:37 am
Location: Plymouth, MN

Re: Intermittent drops in cadence

Post by lorduintah »

I think turning on the Garmin last might be a better sequence - let's see what John has to say.

I say that because of the possible Bluetooth role.
saosijs
Posts: 4
Joined: Sun May 02, 2021 2:56 pm

Re: Intermittent drops in cadence

Post by saosijs »

Interesting you mention Bluetooth ...

From "Instructions Supplement for PowerPod BLE/ANT+ power meter":
3. PowerPod BLE receives speed/cadence data in ANT+ format, and transmits power, speed, and cadence data simultaneously in ANT+ and BLE formats.

In my Edge I only see the PowerPod as Power meter (dumbbell symbol) Network Ant+, and the Garmin speed and cadence sensors.
And if there is some retransmission by the PP, I could see that this has an impact on the Edge, but why would the PP itself also show cadence drops?

Garmin Edge shows them like the attachment (HR strap, cadence, speed, PowerPod).
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mo_mo
Posts: 7
Joined: Mon Sep 21, 2020 10:16 pm

Re: Intermittent drops in cadence

Post by mo_mo »

Check your firmware using Isaac and update if needed. Cadence sensor drop in reading was an issue prior to 8.00. Latest is 8.01:
http://www.ibikesports.com/iBike_update ... 0Notes.pdf
saosijs
Posts: 4
Joined: Sun May 02, 2021 2:56 pm

Re: Intermittent drops in cadence

Post by saosijs »

Thanks, but I guess that is for a different model. I seem to have the latest FW already for my PowerPod BLE:
Firmware.png
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[edit - add comment]

But yes, other devices which received FW 714 in November 2020 got this fix:
Fixed a bug that causes cadence measurements to be incorrect when used with certain cadence sensors, such as Garmin Cadence Sensor 2.

The 641 update is from 2018 so probably this fix did not get ported to my device. Yet, I hope.
Also, strangely, why would the Garmin Edge be impacted, as it connects to the sensor for cadence and not to the PP?
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Intermittent drops in cadence

Post by Velocomp »

This is a bug that is peculiar to the newer version of the Garmin cadence sensor.

We fixed the cadence bug for more recent versions of PowerPod (FW 7.16+), but did not release firmware with the cadence bug fix for older PowerPods using version FW 6.x.

I will see if we can address this problem, but no promises...
John Hamann
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Intermittent drops in cadence

Post by Velocomp »

saosijs wrote: Wed May 05, 2021 3:01 pm Thanks, but I guess that is for a different model. I seem to have the latest FW already for my PowerPod BLE:

Firmware.png


[edit - add comment]

But yes, other devices which received FW 714 in November 2020 got this fix:
Fixed a bug that causes cadence measurements to be incorrect when used with certain cadence sensors, such as Garmin Cadence Sensor 2.

The 641 update is from 2018 so probably this fix did not get ported to my device. Yet, I hope.
Also, strangely, why would the Garmin Edge be impacted, as it connects to the sensor for cadence and not to the PP?
Please email technicalsupport@velocomp.com for next steps.
John Hamann
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