Xbee Data issues after extended sleep period.

Hi all. I am relatively new to Xbee technology but I seem to have encountered an issue that I can’t resolve. My setup is as follows:

I am using a Adafruit Feather ESP8266 that connects via to the internet via wifi and is hardwired to an Xbee S2C as a coordinator. The coordinator is monitoring several Xbee S2C End Devices that are set up to periodically sample some sensor data (1 digital input for a magnetic switch and 1 ADC input for end-device battery voltage) then return to extended sleep. All Xbee’s are running the latest firmware (4060). I have the Xbee End Devices set for Broadcast (DH=0, DL=FFFF) and all devices serial interfacing is set to API with escaping (AP=2, AO=0). I have als turned off the Flow Control (D6=0, D7=0).

My problem is that initially I can establish that the devices are talking using shorter (5 min) sleep times (SP=7D0, SN=0F). However, when I increase the sleep time to beyond 5 minutes (for example 15 mins, SP=7D0, SN=2D), I lose all communication between the Coordinator and End Devices). I have replicated this over several wifi connections, several ESP8266 devices, several coordinators, and several end devices. Always the same result.

A few other settings that may be relevant. I have the end devices sleep mode (SM=4) the sleep time as (ST=1388), the sleep option as (SO=4), and the sampling rate at (IR=FFFF). Also the SP and SN setting for the Coordinator are currently well beyond those set for the end devices (SP=7D0, SN=2D0).

What I need to figure out are the correct settings to sleep the End Devices for 4-6 hours, have them wake up to send 1 message to the coordinator, then return to sleep mode again. I can’t seem to hit the right combinations of Sleep and Sampling settings to do the trick. Anyone have a suggestion for me? Thanks in advance!

Normally the XBee will only wake after SP*SN if there is a ZigBee message waiting for it. I’m not 100% sure on the precise interaction ATIR will have, if it will always force the wake or only fire when it does wake.

It might be worth trying to set SO=0x06 to force wake for ST after SP*SN. Maybe also drop down IR so that it will fire twice in the ST period to be on the safe side.