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Interface:Ethernet:Time Sync:Port:Propagation Delay

Last Modified: September 16, 2019

Provides the propagation delay for the Ethernet cable between this clock and its neighboring clock.

Propagation delay is the time it takes for a single bit to travel along the wire (i.e., PHY to PHY). Propagation delay is a fundamental measurement that is required for time synchronization.

Data type: datatype_icon

Long Name: Interface:Ethernet:Time Sync:Port:Propagation Delay

Class: XNET Session

Permissions: Read

This property uses a double-precision floating-point, and the value is provided in seconds, which is typically used in LabVIEW for relative times. To convert the value to nanoseconds, multiply this property value by 1,000,000,000.

The propagation speed for copper wires is close to 2 * 10^8 meters/second (5 nanoseconds/meter). Therefore, multiplying this property value by 200,000,000 provides a close approximation of the cable length in meters. For example, 800 nanoseconds of propagation delay occurs with approximately 160 meters of copper cable.

For the Protocol of IEEE Std 802.1AS-2011, this property corresponds to the neighborPropDelay attribute, specified in 14.6.7 of IEEE Std 802.1AS-2011.

Where This Property Is Available:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application

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