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XBee 2 sleep mode / initial wake-up

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I have two Xbee S2, first one running as a coordinator in API mode, second one as a router in AT mode.

The router reads an analog value (temp sensor) on its AD3 and sends the value to the coordinator. Please note that this works fine.... until I setup some sleep options.

Now I want to introduce some sleep mode on the router to save battery power. I want it to sleep for 5 minutes, wake up, send on frame with the AD3 sample, then go back to sleep again.

Here are the router settings I'm using:

SM = 0x4
SP = 0x3E8 (=10s)
SN = 0x1E (=30, such that total sleep time is 30x10s = 5min)
ST = 0x1F4 (=500ms, should be sufficient to read analog value and send it to the coordinator...)
SO = 0x6
D3 = 0x2
IR = 0x1388 (=5s, so it has only time to send one sample before it goes to sleep again)

This doesn't work: when I power on the router, it simply sends nothing and it doesn't either wake up after 5 minutes (or so do I think as I don't receive any frame at the coordinator).

I've read there and there that the XBee needs some time to initially join the network... so would 500ms of wake time be sufficient ? Is there some special initial conditions to meet ?

Thanks for your help.
asked Jun 1, 2015 in RF Solutions and XBee by Arno New to the Community (0 points)

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1 Answer

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May I suggest reading over http://knowledge.digi.com/articles/Knowledge_Base_Article/XBee-Cyclic-Sleep-Example-Indirect-Messaging first. Also I would suggest starting with a short sleep cycle. Say 30 seconds.

The wake time also only needs to be 20 - 100ms at most. This is more than enough time for the radio to sample its ADC input and transmit the data.
answered Jun 2, 2015 by mvut Veteran of the Digi Community (15,323 points)