Global Positioning System (GPS) Timestamp from the PXI-6608 Shows a 1 s or 90 ms DelayPrimary Software: Driver Software>>NI-DAQmxPrimary Software Version: 8.0 Primary Software Fixed Version: N/A Secondary Software: N/A Hardware: Counter/Timers (TIO)>>Devices>>PXI-6608
Problem: Why are my GPS timestamps from the PXI-6608 delayed by 1 s or 90 ms? Solution: The PXI-6608 provides a real-time clock which you can synchronize with a Global Positioning System (GPS) receiver that provides an IRIG-B (TTL standards B000, B001, B002, and B003 only) or a pulse per second (PPS) signal. There is a known issue with the calibration constant for the GPS timestamp in NI-DAQmx Driver Version 8.0. To return the accurate GPS timestamp, subtract 90 ms from the value measured by the PXI-6608. In the Traditional DAQ driver, this offset is 1.01 s. The workaround for this issue is to add the offset constant to the timestamp. This issue was fixed in NI-DAQmx 8.1 and later. Related Links: Developer Zone Tutorial: Synchronizing and Correlating Measurements to a Global Timebase with GPS KnowledgeBase 27599UYF: GPS-Based Synchronization on the NI 6608 KnowledgeBase 3OU74CS9: How Do I Configure My 6608 Real-Time Clock for GPS Timing Synchronization? Products and Services: NI PXI-6608 Attachments:
Report Date: 01/31/2006 Last Updated: 01/12/2009 Document ID: 3TUGTUX6 |
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