I constantly encounter an error RXP2P RECEIVE ERROR.
The module (RAK3172-T) settings are the same.
AT+P2P=867100000:7:0:0:8:20
The wires and antennas are fine. There are no short circuits. The antenna parameters correspond to the frequency.
CAD is used.
There is no noise at the selected frequency.
What could be the reason for this error?
Thank You!
Welcome to the forum @SEA
What version of RUI3 are you using (AT+VER=?) ?
Do you have RAK3172 or RAK3172-T with TCXO?
Custom application based on RUI3 or AT command firmware?
What are the settings on the sender?
Thank you for your reply @beegee
The version of RUI3 is AT+VER=RUI_4.2.1_RAK3172-T.
I have RAK3172-T.
Custom application based on RUI3.
The settings on the sender are AT+P2P=867100000:7:0:0:8:20 (they are the same on all modules).
Often, the response does not come from all modules, but each of them sends a response. CAD mode is enabled.
How many devices are sending and how often are they sending?
Your problem could be destroyed payload (e.g. CRC invalid) due to collisions.
CAD can help, but it is not a 100% guarantee that there are no collisions.
Three to ten modules work simultaneously. But even with three working modules, I get an error. Messages are sent on command. Before sending a new message, I wait for the transmission to complete.
Added a minimum and maximum waiting time interval for the response.
Added a random delay before responding (within the interval), which is calculated based on the device ID and the counter.
The frequency of the error has decreased. But I still see it quite often.
What is the delay between each transmission on the sending device?
It’s between 100 and 1000 milliseconds now. This interval is tunable. Through a custom AT command.
You mean you try to send every 100 milliseconds on a device?
Impossible.
A transmission of only 8 bytes with your settings will take already ~830 milliseconds.
In other words, are you suggesting that the delay before responding should be a bit longer than the Air time?
900 ms for example.
It depends on your payload size and transmission settings.
You can use the calculator tool from Semtech to get the minimum delay between two transmissions.
The tool I used is an old one, they have now an online version: