Select clock priorities

Override the best master clock algorithm to choose a different grandmaster for these cases:
  • Knowledge about the reliability or availability of clocks with similar quality values.
  • Avoid the clock choice being based on arbitrary values such as device serial numbers or MAC addresses.
  • Avoid the clock choice changing when modules are replaced for maintenance purposes.
In these cases, changing the default priority
values can make it easier to predict or control which clock is chosen as grandmaster.
TIP:
For large system where there are only a few devices to avoid using, set the priority values for those devices to greater than 128 (default value) and let the remaining devices (including new, out-of-box devices added later) negotiate normally. If only a few devices are using a grandmaster, set their priority values to less than 128.
To select clock priorities:
  1. In the
    Controller Organizer
    , right-click the controller and choose
    Properties
    . The
    Controller Properties
    dialog box opens.
  2. Select the
    Date/Time
     tab.
  3. If it is not already selected, select
    Enable Time Synchronization
    .
  4. Select the
    Advanced
    button. The
    Controller Properties
     dialog box -
    Advance Time Sync
     tab opens.
  5. To override the actual clock quality values (Priority 1) or override a tie breaker (Priority 2) between two devices that are equal in clock quality, under
    Local Clock
    , enter or select the
    Priority 1
     or
    Priority 2
     value.
    The priority values range from 0 through 255, with zero being the highest priority.
  6. Select
    Apply
    .
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