XBee in pin sleep mode don't wake up again after the signal goes back to non sleep level

We are developing a batterie driven data collection system with a PIC 24F microcontroller and a XBee S2 radio modul. To reduce the power demand of the XBee we want to use the sleep functionality. This will be triggered by the PIC on the respective pin on the XBee module. Our problem is that we can set the XBee to sleep by a high signal on the XBee sleep pin but the modul don’t wake up again after the signal goes back to low level.

We have the Firmware Version 1341 and the Hardware Version 1945 on the XBee S2 modul.

To illustrate the situation I add a timing diagram. At time point 1 of the diagram we send some API commands to the XBee module and receive the propper responses. Than we set the XBee to sleep by setting the sleep pin to high level (this is shown on the line “XBee Sleep”. The time between setting to sleep and waking up is 5 sec (time between 1 and 2: 5 sec) and the time after waking up to the first API command is 3 sec (time between 2 and 3: 3 sec). Both timings should be enough from my perspective. At time point 3 we send a valid API command to the XBee but get no answer. Thats the problem.

The firmware version you are using is out of date and no longer supported. Try upgrading to the current XBee ZB function sets instead. You can see how to do that by going to http://www.digi.com/support/kbase/kbaseresultdetl?id=3025