Time to wait between SEND and SLEEP

LPWAN Modules / EVBs RAK3172
1

I am working on a low power device and I have noticed that I must wait at least 3 seconds between a successful AT+SEND command and AT+SLEEP, otherwise the sleep will not occur or only be very brief.

Given that the SEND returns OK, it seems like I should be able to sleep straight away. Is there anyway to query the device to make sure it can enter sleep?I have found 3 seconds to work well but that might be because I am testing right next to my gateway. When I deploy this in the field the time required might increase.

The current sent of commands which works well is as follows

>>>>>>AT+SEND=50:112233445566778899
<<<<<<OK
<Wait 3 seconds>
>>>>>>AT+SLEEP=0

If I instead use

>>>>>>AT+SEND=50:112233445566778899
<<<<<<OK
>>>>>>AT+SLEEP=0
<sleep my mcu>

I see from my power supply that the mcu is sleeping but the RAK3172 is not.

2

Hi @WillAnderson ,

The module won’t be able to sleep immediately because it has to open its RF based on the LoRaWAN RX1 and RX2 delay (if working on class A). I am not sure what network server you are using but the standard will allow up to 15seconds RX1 delay (usually this is way less - timeout in TTN V3 is 5 sec) plus the RX2 delay which is 1 second after.

I understand your concern about this that’s why on our next firmware release, we will have the automatic low power mode like the legacy firmware where the module will go back to sleep automatically after execution of commands.