User manual

Toolbox 32 User Manual 1.47d www.cse-semaphore.com/mykingfisher
Page
139
Example - Synchronizing RTU Clocks
Each RTU has a clock that can be synchronized periodically to ensure that data is logged with a precise time
stamp.
There are various factors that affect the accuracy of clock synchronizing: drifting of the RTU's own clock,
transmission time to set the clock, and accuracy of the source clock.
• The most accurate way to maintain clock accuracy is to use a CP-21 GPS option board. This allows the
RTU's clock to be set within 10 milliseconds (10 thousandths of a second) of GMT. Please see the topic
Driver - GPS.
• RTUs are also able to synchronize time between themselves. A master RTU can send a command to
one or more outstations to synchronize all their clocks to its own clock. The RTU clocks will then be
accurate to within 15 milliseconds. Please see the topic Ladder Logic - Clock Synchronization for details.
• An RTU clock can be manually updated by setting the hours, minutes, seconds and milliseconds
registers of the RTU clock using Toolbox or SCADA software. Accuracy is dependent on the person or
device used to set these registers. An example of doing this is shown below.
│ │
├ Set clock when time setpoints change ┼ ┤
│ │
│HourSetpoint HourSetpoint Set Hours │
│ #R51 #R51 #YHOUR │
├──[CHANGE]────────[≤]───────────────────────────────────────────────(Copy)────┤
│ 23 #R51 │
│MinSetpoint MinSetpoint Set Minutes │
│ #R52 #R52 #YMIN │
├──[CHANGE]────────[≤]───────────────────────────────────────────────(Copy)────┤
│ 59 #R52 │
│SecSetpoint SecSetpoint Set Seconds │
│ #R53 #R53 #YSEC │
├──[CHANGE]────────[≤]───────────────────────────────────────────────(Copy)────┤
│ 59 #R53 │
│ │
• RTUs also recognise a DNP3 or Kingfisher protocol function code that allows their clock to be set to
millisecond accuracy.