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-   -   SRM data sample rate with Wahoo units (https://www.bikeforums.net/track-cycling-velodrome-racing-training-area/1159669-srm-data-sample-rate-wahoo-units.html)

bartek. 11-06-18 10:41 AM

SRM data sample rate with Wahoo units
 
Hi,

I can't find any information regarding data sample rate for Wahoo head units. AFAIR the SRM PM has 1sec data sample rate for Garmin units via Ant+ and 0.1sec for PC8 (ANT+? BT Smart?).

Anyone could give some reliable information about the sampling? I can be wrong here (correct me please) but SRM Science Track PowerMeter supports both ANT+ and BT, right? So how does it go with Wahoo head units which supports both protocols? What sampling rate can be achieved with using which protocol here?

Looking for a replacement for my Garmin Edge 810 and my 2 current options are Wahoo Elemnt Bolt or Edge 520 plus (PC8 is a way too expensive). Which one would be better for track purposes (I have enough information for other disciplines but don't want to be disappointed on track after buying a new unit)?

colnago62 11-06-18 12:52 PM


Originally Posted by bartek. (Post 20650864)
Hi,

I can't find any information regarding data sample rate for Wahoo head units. AFAIR the SRM PM has 1sec data sample rate for Garmin units via Ant+ and 0.1sec for PC8 (ANT+? BT Smart?).

Anyone could give some reliable information about the sampling? I can be wrong here (correct me please) but SRM Science Track PowerMeter supports both ANT+ and BT, right? So how does it go with Wahoo head units which supports both protocols? What sampling rate can be achieved with using which protocol here?

Looking for a replacement for my Garmin Edge 810 and my 2 current options are Wahoo Elemnt Bolt or Edge 520 plus (PC8 is a way too expensive). Which one would be better for track purposes (I have enough information for other disciplines but don't want to be disappointed on track after buying a new unit)?

I do not have a track SRM, I have the Origin on two road bikes. There is an issue with cadence reporting with the Wahoo and my SRM. The numbers for cadence and average cadence are way off. I know it is a Wahoo issue because the SRM works flawlessly with my Garmin. The Wahoo also has an issue with pc6 board from SRM.

carleton 11-06-18 01:49 PM

I would consider the SRM PC 7. It samples every 0.5 (PC8 is 1, if I remember correctly). PC7 is moderately priced and even cheaper if you buy refurbished from SRM. It is ANT+ as well. No SRM cranks required.

topflightpro 11-07-18 07:46 AM

Yeah, you should be able to find a PC7 used for about $150. But it does not have GPS - not really an issue for the track but could be if you plan to use it elsewhere.

bartek. 11-10-18 01:48 PM


Originally Posted by colnago62 (Post 20651103)
I do not have a track SRM, I have the Origin on two road bikes. There is an issue with cadence reporting with the Wahoo and my SRM. The numbers for cadence and average cadence are way off. I know it is a Wahoo issue because the SRM works flawlessly with my Garmin. The Wahoo also has an issue with pc6 board from SRM.

It's pretty strange. Maybe I will arrange the wahoo unit first for checking if the cadence in my case is correct. I assume the difference is noticeable quickly?
Could please verify the data sample rate for me? Simple read FIT file with a record with your SRM power meter. In my case, it's every 1 second but I use Garmin.


Originally Posted by carleton
I would consider the SRM PC 7. It samples every 0.5 (PC8 is 1, if I remember correctly). PC7 is moderately priced and even cheaper if you buy refurbished from SRM. It is ANT+ as well. No SRM cranks required.

This could be an option too. Unfortunately, I can't find anything cheap. Maybe looking in a wrong place but I see prices above $1000 :( For a good price I could go with wahoo/garmin on my road/cx bikes and keep PC7 for track only. As I would need recollect all mounts for wahoo anyway (integra stem, oval pro missile tt, saddle rail) I could go with SRM versions. But it's definitely not worth $1000.

bartek. 11-10-18 01:58 PM

EDIT. OK. Got a wrong example at first. Prices are a way below $1000. I can see some units for circa $120 used on eBay. This is definitely something to consider. However I still need to know if I should switch my Garmin Edge 820 to Edge 520 or Wahoo Elemnt Bolt ;-)

colnago62 11-10-18 09:30 PM

Do I find the file on the Wahoo unit?

bartek. 11-11-18 10:36 AM

Sure thing, simple connect wahoo to your laptop: https://support.wahoofitness.com/hc/...ptop-Computers

Morelock 01-11-19 09:13 AM

random necro, I see @carleton and @topflightpro suggest the PC7 does pair with non-srm power meters, but google fu seems to suggest it does not. (only reads ant+ ctf protocol) Any clarification? I might pick one up if it works with other stuff.

carleton 01-11-19 10:21 AM


Originally Posted by Morelock (Post 20742705)
random necro, I see @carleton and @topflightpro suggest the PC7 does pair with non-srm power meters, but google fu seems to suggest it does not. (only reads ant+ ctf protocol) Any clarification? I might pick one up if it works with other stuff.

The PC7 is an ANT+ head unit. If the power meter works with ANT+ head units, it will work.

ANT+ is a standard (created by Garmin, I believe) that many manufacturers use.

carleton 01-11-19 10:23 AM

https://en.m.wikipedia.org/wiki/ANT%2B


ANT+[1] (pronounced ant plus) is a wireless protocol for monitoring sensor data such as a person's heart rate or a bicycle's tyre/tire pressure, as well as the control of systems like indoor lighting or a television set. ANT+ is designed and maintained by the ANT+ Alliance which is managed by ANT Wireless, a division of Dynatream Innovations owned by Garmin.[2] It is based on the ANT protocol.[3]

Morelock 01-11-19 11:26 AM

@carleton

Yeah, it would seem that way from a quick glance, but deeper looking on the web suggests otherwise. The SRM PC7 uses ANT+, but something is different than what's transmitted by non-srm units (quarq's can be modified to work in "srm emulation" mode and will work)

That's what I found from the internet anyways.

carleton 01-11-19 11:33 AM


Originally Posted by Morelock (Post 20742934)
@carleton

Yeah, it would seem that way from a quick glance, but deeper looking on the web suggests otherwise. The SRM PC7 uses ANT+, but something is different than what's transmitted by non-srm units (quarq's can be modified to work in "srm emulation" mode and will work)

That's what I found from the internet anyways.

Will you cite exactly what they are saying?

Morelock 01-11-19 11:41 AM

Sorry on mobile for a while, here is a post
weightweenies.starbike.com/forum/viewtopic.php?t=134939
Searching slowtwitch forums seems to confirm in multiple threads as well. In dcrainmakers stages review comments someone asks about stages /pc7 compatibility and a stages rep says no it won't work.

Hmm

topflightpro 01-11-19 11:53 AM

My comment was directed to the OP, who was using the most recent version SRM Track, which should work with the PC7.

The PC8 should work with non-SRM PMs. I cannot speak to whether the PC7 does.

carleton 01-11-19 11:53 AM


Originally Posted by Morelock (Post 20742960)
Sorry on mobile for a while, here is a post
weightweenies.starbike.com/forum/viewtopic.php?t=134939
Searching slowtwitch forums seems to confirm in multiple threads as well. In dcrainmakers stages review comments someone asks about stages /pc7 compatibility and a stages rep says no it won't work.

Hmm

I read the first post and immediately know the issue. The user has to configure the head unit to either receive cadence as a separate signal than power or on the same signal (I cant recall which one). The fact that cadence is missing is the key clue. Cadence is required to calculate power.

Its a configuration error.

I dealt with this when I had a PC7 head unit paired with an ANT+ cadence sensor then switched to using SRM PM cranks. I had to go into the software (or menus on the head unit) and reconfigure it.

carleton 01-11-19 01:01 PM

Basically, I recall the menu being something like:

Option 1:
- Speed + Cadence Sensor signal
​​​​​​- Power Meter signal

Option 2:
- Speed Sensor signal
- Power Meter + Cadence Sensor signal

Option 3:
- Speed Sensor signal
- Cadence Sensor signal
- Power Meter signal


Each sensor has a unique ANT+ ID that is stored in the head unit and when stored, the head unit listens for those particular signals and records the data they transmit.

Cool fact: Speed sensors can be used as Cadence sensors and vice-versa. They are basic reed switches and dont carry any extra data like Power Meter sensors.

Morelock 01-11-19 02:47 PM

Back to a real comp :D
I follow what you're saying @carleton, mainly because it just makes sense that it should work with ANT units... but I don't find anyone online that has successfully done it with anything except a Quarq.
(fwiw, if seller accepts my offer I'll just buy the thing and test it myself... I'm sure I'll end up with another SRM unit sooner or later)


https://forum.slowtwitch.com/forum/S...20pc7#p6587167
https://forum.slowtwitch.com/forum/S...20pc7#p6408374

highlight
PC7s speak a non-ant standard, and so they dont work with a generic powermeter. That said, Quarq has implemented the specific PC7 protocol (it used to be name German Achievement Mode, or GAM)

Morelock 01-11-19 04:04 PM

@carleton
I'm with you, that's how Ant(+) should work. I've found nothing online indicating it DOES work that way with the pc7, and a lot that say's it doesn't work at all with any other PM besides the SRM (and some quarqs)
basically here
here
and
here


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