This page shows the slave device EtherCAT-specific distributed clock properties. The distributed clock can enable all the slave devices to have the same time. The first slave device with the distributed clock enabled is the clock master. The clock of the clock master synchronizes the clocks in the other slave devices and master.

This page includes the following components:

  • Enable distributed clock—Specifies whether to enable the distributed clock.
  • Synchronization Signal (SYNC0) Interval—Specifies the interval of SYNC0. The distributed clock synchronization signal is SYNC0. A device usually processes the data at SYNC0.
    • Cycle Time (scan periods)—Specifies the SYNC0 cycle time.
    • Shift Time (microseconds)—Specifies the SYNC0 shift time within a synchronization interval.
  • Auxiliary Synchronization Signal (SYNC1) Interval—Specifies the SYNC1 interval. The auxiliary synchronization signal is SYNC1. A slave device can process the additional data at SYNC1.
    • Enable SYNC1—Specifies whether to enable SYNC1.
    • Cycle Time (SYNC0 cycles)—Specifies the SYNC1 cycle time.
  • Synchronize Input and Output—Specifies settings to synchronize the input and output with the distributed clock. The NI EtherCAT slave devices implement the simultaneous sampling with these settings enabled.
    • Synchronize Input Mode—Specifies the mode to synchronize the input with the distributed clock.
      • Unsynchronized—No synchronization.
      • Synchronized to EtherCAT frame—Synchronize the input to the EtherCAT frame.
      • Synchronized to distributed clock—Synchronize the input to the distributed clock.
    • Input Correction (microseconds)—Specifies the correction time to synchronize the input.
    • Synchronize Output Mode—Specifies the mode to synchronize the output with the distributed clock.
      • Unsynchronized—No synchronization.
      • Synchronized to EtherCAT frame—Synchronize the output to the EtherCAT frame.
      • Synchronized to distributed clock—Synchronize the output to the distributed clock.
    • Output Correction (microseconds)—Specifies the correction time to synchronize the output.

For the four-adapter slave device, you must uncheck Enable. Otherwise, the device cannot work properly.

The SYNC0 cycle time is a multiple of the scan period. You can change the scan period by configuring the scan engine.

If you specify improper values for Input Correction and Output Correction, the slave device enters the error mode. The NI slave device returns the error Timing monitors have detected a synchronization or timing error.

The following figure describes the distributed clock-related properties.