XBEE SERIE 1 SLEEP MODE

Hi,

I'm using 2 xbee with an arduino each one . The end device has to send a sensor value with a period of 5 seconds so I want to put the xbee in sleep mode when it's not sending the sensor value. The problem is that when i don't use sleep mode, it works fine , in the other hand, when i put the end device in the sleep mode, it doesn't conntec to the coordinator.

I configure it with XCUT.

End Device Configuration:
SM=4 . Sleep Mode cycle
ST = 500 ms . Time before sleeping
SP= 4000 ms. Sleep time.
DP= 10--268 s. I'm not sure about it is. I think is the time which xbee sleep if it not finds a coordinator. I've tryed a lot osf values and it's not working.