Cannot send commands to child after a while

Question

Dear Sirs,

I am using xbee3 zigbee as coordinator and several Texas Instrument cc2530 end devices.

I am using xbee3 connected to raspberry pi through serial communication. After a while (1-2 days), one and then two and then all end device stop receiving commands from coordinator.

To be more precise, when end device are still receiving commands:
1) when they send measurements (end device are sensors): 
"type: 145,
  remote64: '00124b001735a8cc',
  remote16: '5a02',
  sourceEndpoint: '02',
  destinationEndpoint: '02',
  clusterId: '0001',
  profileId: 'ffff',
  receiveOptions: 16,
  data: <Buffer 73 65 6e 73 52 3a 30 30 31 32 34 42 30 30 31 37 33 35 41 38 43 43 68 75 6d 3a 38 35 2e 36 74 65 6d 70 3a 31 35 2e 36 38 43 00>
}
115,101,110,115,82,58,48,48,49,50,52,66,48,48,49,55,51,53,65,56,67,67,104,117,109,58,56,53,46,54,116,101,109,112,58,49,53,46,54,56,67,0
0: sensR:00124B001735A8CChum:85.6temp:15.68C"

2) and when sending commands:
"query: [Object: null prototype] { cmd: 'ATplusUCAST:00124B001735A8CC,S' }
cmd: AT+UCAST:00124B001735A8CC,S addr: 00124B001735A8CC
query: [Object: null prototype] {}
>> {
  type: 139,
  id: 1,
  remote16: '5a02',
  transmitRetryCount: 0,
  deliveryStatus: 0,
  discoveryStatus: 64
}
>> {
  type: 145,
  remote64: '00124b001735a8cc',
  remote16: '5a02',
  sourceEndpoint: '02',
  destinationEndpoint: '02',
  clusterId: '0001',
  profileId: 'ffff',
  receiveOptions: 16,
  data: <Buffer 53 65 6e 73 6f 72 43 3a 30 30 31 32 34 42 30 30 31 37 33 35 41 38 43 43 2c 53 32 20 56 44 44 32 34 33 32 34 20 4f 4b 00>
}
83,101,110,115,111,114,67,58,48,48,49,50,52,66,48,48,49,55,51,53,65,56,67,67,44,83,50,32,86,68,68,50,52,51,50,52,32,79,75,0
37: SensorC:00124B001735A8CC,S2 VDD24324 OK"

After 1-2 days, when end device are no longer responding to commands:
3) when they send measurements, I get:
"type: 145,
  remote64: 'ffffffffffffffff',
  remote16: '3cb4',
  sourceEndpoint: '02',
  destinationEndpoint: '02',
  clusterId: '0001',
  profileId: 'ffff',
  receiveOptions: 16,
  data: <Buffer 73 65 6e 73 52 3a 30 30 31 32 34 42 30 30 31 39 41 35 46 33 41 33 68 75 6d 3a 38 33 2e 36 74 65 6d 70 3a 31 35 2e 36 39 43 00>
}"

remote64 field has no longer 64-bits address.

4) When I try to send command (I am using only 64-bits address to send commands), I get:  "query: [Object: null prototype] { cmd: 'ATplusUCAST:00124B0019A5F3A3,S' }
cmd: AT+UCAST:00124B0019A5F3A3,S addr: 00124B0019A5F3A3
>> {
  type: 139,
  id: 1,
  remote16: 'fffd',
  transmitRetryCount: 0,
  deliveryStatus: 36, 
  discoveryStatus: 1 
}"

 
It seems that xbee loses end devices 64bit addresses.

If I power off and power on after a while raspberry pi+xbee, the problem is solved and end devices receive correctly the commands sent by xbee.

What could be the problem? 

Answer 1

Check your sleep timing settings on both the end devices and the Coordinator. They should match.

Comments

Thank you very much for your answer.

Now I am not quite sure which sleep timing setting should I correct.

End devices sleep 1min. before polling for any command.

Xbee coordinator sleep timing settings:
SM: no sleep
SP: AF0
ST: 1388
SN: FFFF
ET: 2 minutes.

SP=AF0=28 seconds which is lower than 1 minute but my application keeps sending commands through xbee to end devices during 5 minutes, until it gets an answer. And it works during 2-3 days.

On top of that, child poll timeout is at the maximum, 2 months, and not 2-3 days.

Does it have anything to do with NT that is equal to 3C ?

I got also for the first time this error yesterday: "java.lang.IllegalArgumentException: 64-bit address cannot be unknown." Maybe it has nothing to do with this problem...

May it be a firmware bug? I am using zigbee v1009.