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Wireless Watchdog

If a wireless connection is unreliable, one way to mitigate the unintended loss of connection is to use a feature that monitors the continuity of the connection, and reboots the device if the connection or data flow has not been maintained for a configurable amount of time.

After restart, the device will attempt to re-establish the connection.

Note

This feature is not needed under normal conditions.
It should be enabled only when investigating an issue, and should not be required during typical use.

Info

If the device encounters conditions that hinder or prevent data transmission, it may automatically reboot to restore functionality and resume transmission as soon as conditions improve.

In operation, a timer maintains a counter to measure the period since the last received wireless packet or correctly connected state.
If this period exceeds a user-configurable value, the device reboots.

This counter can be checked to verify operation, and is reset back to zero on every incoming wireless packet, and the monitoring continues.

Object Dictionary parameters

  • 0x3333:0x80 [Wireless Interface Watchdog Period]
    The period in seconds after which the device restarts after no wireless packets received, or no connection.
    A period up to 65,535 seconds (over 18 hours) can be specified.

  • 0x3333:0x81 [Wireless Interface Watchdog Tick]
    This value increments every second (if the feature is enabled) up to the value in 0x3333:0x80.

  • 0x3333:0x82 [Wireless Interface Watchdog No Connection]
    The number of times the device has restarted due to this feature because of no connection for the entire period.

  • 0x3333:0x83 [Wireless Interface Watchdog No Data]
    The number of times the device has restarted due to this feature because of no data received (but with a valid connection) for the period. This could be useful for issue investigation.

  • 0x3333:0x84 [Wireless Interface Watchdog Restarts Count]
    This is the sum of both 0x82 and 0x83.

Set Parameters

Set 0x3333:0x80 [Wireless Interface Watchdog Period] to the value in seconds of the duration before reboot if either:

  • no wireless traffic is received, or
  • no connection has been made.

A value of 0 disables this feature, and is the default.
The minimum value that can be set is 90 (seconds).

The recommended minimum time is 120 seconds to prevent unnecessary reboots before a connection can be established.
Also, this period must be greater than the 0x3333:0x08 [Time in seconds to sleep mode] in order for the Sleep function to work.

Every write to this object applies the new period immediately and resets all counters (0x81, 0x82, 0x83, 0x84).

Tip

This object is non-volatile, so will remain functional until disabled by writing 0 to 0x3333:0x80. (Or a factory reset).

Check Watchdog operation

When enabled, periodically (every few seconds) read 0x3333:0x81 [Wireless Interface Watchdog Tick].
The value will increase every second until reaching the Wireless Interface Watchdog Period, indicating that the function is operating.

Verify Watchdog action

  1. Check 0x3333:0x84 [Wireless Interface Watchdog Restarts Count] value.

  2. Set 0x3333:0x80 [Wireless Interface Watchdog Period] to 120.

  3. Make no connection to the device.

  4. After 120 seconds, the device will reset:

    a. Both LEDs briefly turn off

    b. Both 0x3333:0x82 [Wireless Interface Watchdog No Connection] and 0x3333:0x84 [Wireless Interface Watchdog Restarts Count] will increment by one to indicate that the Watchdog was the reason for the reset.

  5. The device continues to operate in this mode, incrementing the 0x3333:0x81 counter every second; the 0x3333:0x84 every two minutes, and waiting for traffic to be received.