User Manual
Table Of Contents
- 1. Overview
- 2. RF Module Operation
- 3. XBee ZigBee Networks
- Introduction to ZigBee
- ZigBee Stack Layers
- Networking Concepts
- ZigBee Application Layers: In Depth
- Coordinator Operation
- Router Operation
- End Device Operation
- Channel Scanning
- 4. Transmission, Addressing, and Routing
- 5. Security
- 6. Network Commissioning and Diagnostics
- 7. Managing End Devices
- 8. XBee Analog and Digital IO Lines
- 9. API Operation
- API Frame Specifications
- API UART Exchanges
- Supporting the API
- API Frames
- AT Command
- AT Command - Queue Parameter Value
- ZigBee Transmit Request
- Explicit Addressing ZigBee Command Frame
- Remote AT Command Request
- Create Source Route
- AT Command Response
- Modem Status
- ZigBee Transmit Status
- ZigBee Receive Packet
- ZigBee Explicit Rx Indicator
- ZigBee IO Data Sample Rx Indicator
- XBee Sensor Read Indicator
- Node Identification Indicator
- Remote Command Response
- Over-the-Air Firmware Update Status
- Route Record Indicator
- Many-to-One Route Request Indicator
- Sending ZigBee Device Objects (ZDO) Commands with the API
- Sending ZigBee Cluster Library (ZCL) Commands with the API
- Sending Public Profile Commands with the API
- 10. XBee Command Reference Tables
- 11. Module Support
- Appendix A: Definitions
- Appendix B: Agency Certifications
- Appendix C: Migrating from ZNet 2.5 to XBee ZB
- Appendix D: Additional Information
XBee®/XBee‐PRO®ZBRFModules
©2011DigiInternational,Inc. 44
Network Watchdog
The NW command (network watchdog timeout) can be used for a powered router to periodically check for
the presence of a coordinator to verify network connectivity. The NW command specifies a timeout in
minutes where the router must receive communication from the coordinator or data collector. The following
events restart the network watchdog timer:
•RF data received from the coordinator
•RF data sent to the coordinator and an acknowledgment was received
•Many-to-one route request was received (from any device)
•Changing the value of NW.
If the watchdog timer expires (no valid data received for NW time), the router will attempt to discover the
64-bit address of the coordinator. If the address cannot be discovered, the router records one watchdog
timeout. Once three consecutive network watchdog timeouts have expired (3 * NW) and the coordinator
has not responded to the address discovery attempts, the router will leave the network and attempt to join
a new network. Anytime a router receives valid data from the coordinator or data collector, it will clear the
watchdog timeouts counter and restart the watchdog timer. The watchdog timer (NW command) is settable
to several days. The network watchdog feature is disabled by default (NW defaults to 0).