ANT Forum

I am currently using the ANT+ Verification Tool v.1.3.3 to test a Power Only Bike Power Sensor. All tests pass apart from Transmission Pattern Test where i get around 15-20% message failures do to poor RF. Is this a real failure i.e. due to its design or is it outside interference?

I have had the same code and hardware design pass all the tests before so i am hoping that it is due to external stuff.

Any advice?      

It is known issue of the verification tool, it will be fixed in next release. Instead, you can manually check if the rotation of the data pages were transmitted following the requests which are specified in PWR device profile.      

Verification Tool 1.3.3 Pattern Test on my Bike Power sensor produces this output:

Test#6: Transmission Pattern Test
Result: Fail!
0.33% of messages failed to be received.
Test on data page 16 in decimated stream #1 passed with 99.57% of latencies within acceptable tolerance.
Failure due to page 17 latencies in decimated stream #1 with only 74.15% within acceptable tolerance.
Test on data page 80 in decimated stream #1 passed with 100.00% of latencies within acceptable tolerance.
Test on data page 81 in decimated stream #1 passed with 100.00% of latencies within acceptable tolerance.

Is this likely due to the Verification Tool issue described in the previous post, or have I missed something basic in my design?

What I want is to have speed, distance, total power and left/right fraction sent from my sensor to a Bike Power display, so I send a mix of power-only (0x10), wheel-torque (0x11), manufacturer-data (0x50) and product-data (0x51) according to my interpretation of the Bike Power requirements. A data page is sent each time the EVENT_TX is received, in a sequence that repeats after 120 pages: the 60th page is mfgr, the 120th page is product, all other multiples of 5 are power and all others are torque. Thus, most of the sequence is 0x11, 0x11, 0x11, 0x11, 0x10, 0x11, 0x11, 0x11, 0x10 ...

Reading Table 5-6 of the ANT+ Certification Device Profile Test Spec I see that the maximum latency (Lmax) for page 0x11 is 1! A latency of 1 appears to mean that no other page can intervene, making my mixed data stream illegal.

Any clarification would be much appreciated. Thank you.
     

Hi!

This is a known issue with the tool and spec. It will be fixed in the next release. If you send all the pages as the profile describes, then you will pass using the updated tool. I'll put a note here when the release is available.

Thanks,

Kat      

Kat - Thanks very much for the instant explanation. One more question: In the Verification Tool, Step 1, offers "Power Only" and "Torque at Wheel"; should I be using the "Torque at Wheel" test with my sensor that sends a mixture of the two data pages?      

Yes. The 'power-only' page is always required, whereas 'torque at wheel' is optional, so torque at wheel implies both pages are being used.