ANT Forum

Hello,

i open 4 ANT+ profile channels simultaneously as slave device (for example Bike Power, Bike Speed, Cadence and HRM). The High Prio Search is set to 0 sec and the Low Prio Search is set to 30 sec. To Send the data for these profiles i juse the ANT+ Sensor Simulator. In normal operation i get the data from all channels. Now i disconnect all channel in the ANT+ Sensor Simulator simultaneously. After 30 sec i get the first RX_SEARCH_TIMOUT event from the AP2 module and after again 30 sec I receive the second RX_SEARCH_TIMOUT event message. For the third and fourth profile the same. So to get the RX_SEARCH_TIMOUT event for all channels it takes 2 min.

Is that normal? Or should I get the RX_SEARCH_TIMOUT event for all profiles after 30 sec simultaneously?      

Hi,

This is normal behaviour, each search time will stack with every other channel which has dropped to search, ensuring that each channel will receive it's minimum scanning time.
This does not mean the AP2 cannot scan for multiple masters simultaneously, but that is dependent on whether the channels which have dropped to search share similar networks. The search times will still stack.

Cheers      

Hello,

first, thanks for your help.

Now i have a nother question.

Example configuration (all channels are open as slave):
- Firt AP2 channel is open with HRM profile
- Second AP2 channel is open with Bike Power profile
- Third AP2 channel is open with Bike Speed profile
- Fourth AP2 channel is open with Bike Cadence profile

All profile data are send with the ANT+ Sensor Simulator. Now i disconnect all channel in the ANT+ Sensor Simulator simultaneously.

For the firt AP2 channel i get the RX_SEARCH_TIMOUT event after 30 sec. When i get the event i open the channel again. After again 30 sec i get the RX_SEARCH_TIMOUT event for the second AP2 channel and open the channel again. All channels are still disconnect in the ANT+ Sensor Simulator. After 30 sec i get the RX_SEARCH_TIMOUT event for the first AP2 channel again. But i never get the RX_SEARCH_TIMOUT event for the third and fourth channel.

Is that because i reopen the first and second channels again after the RX_SEARCH_TIMOUT event? If i get the RX_SEARCH_TIMOUT event from the first channel and reopen it with the fifth AP2 cannel, would it work then?      

Hi,

In terms of operation the order should not matter much since all of these channels share the same radio frequency and network (key), meaning ANT will be searching for all of these device ID's simultaneously.

But yes, in terms of search stack order priority, typically the timeouts occur in order from channel 0 to 7, so if you have channels 0-3 open and channel 1 times out, the next timeouts will be 0 > 2 > 3.

In terms of behavior, if you wanted to prioritize a certain channel being found first (not sharing same same RF/network), I would set it to have a high priority search, while the other channels would be set to low priority search, this would not change how the timeouts stack however.

If you feel it's necessary to have them stack in order then yes, if you reopen your closed channel 0 onto channel 5, then next channel 1 > 2 > 3 > 4 > 5, etc would timeout.

I would recommend reading the AN 15 - Multi Channel Design Considerations application note, particularly the section on searching more than one channel for more information.

Cheers