Simcenter Testing Solutions What is the phase match between distributed Simcenter SCADAS XS systems using GPS or IEEE15888 synchronization protocols?

2021-12-06T11:31:32.000-0500
Simcenter SCADAS

Summary

The following table summarizes phase measurements done to check the phase accuracy at 20 kHz between inputs of channels measured on two different Simcenter SCADAS XS where the synchronization was done with 3 different scenarios.

Details

The following table summarizes phase measurements done to check the phase accuracy at 20 kHz between inputs of channels measured on two different Simcenter SCADAS XS where the synchronization was done with 3 different scenarios.
 
 GPS-GPS*IEEE1588IEEE1588+GPS
Jitter in nsec1252550
Phase difference in degree unknown±0.2°±0.4°
 
*Note:  Phase accuracy depends on environmental conditions such as GPS satellites in view, reflections from buildings, atmospheric conditions etc… In one specific test setup, two XS systems were measuring independently each locked to GPS time. The GPS antennas were close to each other and GPS satellite visibility was optimal. Both XS systems were viewing the same GPS satellites. In this ideal situation, phase differences of ±1° (at 20 kHz) were observed. This figure should be considered as a theoretical lower limit only. It is not possible to provide a correct or generic number for all possible test situations.

Synchronization scenarios:
  1. GPS – GPS: Simcenter SCADAS XSs are physically not connected to each other. Synchronization is done via GPS time stamping (“Clock Sync” setting in Channel Setup). Data merging is done in Simcenter Testlab Time Data Selection (How can I synchronize and merge time data recorded by two different systems? )
  2. IEEE1588: Simcenter SCADAS XS systems are connected in Master/Master configuration (supported from LMS Test.Lab 16A with XS-‘N’ version only) connected to each other with a PTP (Precision Time Protocol) switch and synchronized through IEEE1588 protocol. The phase accuracy is measured between tri-axial inputs of channels on two Simcenter SCADAS XSs in the PTP-connected clusters.
  3. IEEE1588 – GPS: Simcenter SCADAS XS systems are connected in Master/Master configuration (supported from LMS Test.Lab 16A with XS-‘N’ version only) connected to each other with an IEEE1588 PTP synchronized cluster that uses the GPS as reference clock. The phase accuracy was measured between tri-axial input channels of two Simcenter SCADAS XSs in the PTP-connected clusters.
Conclusion:

The highest synchronization accuracy can be achieved by using the IEEE1588 Precision Time Protocol in Master-Master setup. However for several applications, where the cable length is a limiting factor, GPS-to-GPS synchronization is an accurate and flexible solution.
 

KB Article ID# KB000032106_EN_US

Contents

SummaryDetails

Associated Components

SCADAS Durability SCADAS III SCADAS Lab SCADAS Mobile SCADAS PBN SCADAS RS Configuration App SCADAS RS Hardware SCADAS RS Recorder App SCADAS Recorder SCADAS XS