PXI-6683H GPS, IEEE 1588 and IRIG-B Synchronization Module
The NI PXI-6683H is a timing and synchronization module designed to coordinate PXI and PXI Express systems using GPS, IEEE 1588 Precision Time Protocol and IRIG-B time references. It can synchronize clocks, timestamps and trigger events across geographically separated measurement systems.
The module includes a 10 MHz temperature-compensated crystal oscillator, a GPS receiver, Gigabit Ethernet connectivity, a 10 MHz clock output and three programmable function interface connections. Unlike the PXI-6683, the PXI-6683H does not include an external CLKIN connector or PXI Star trigger routing.
Key Features of the PXI-6683H
- GPS-based time synchronization
- IEEE 1588 Precision Time Protocol support
- IRIG-B AM and DC input support
- 10 MHz onboard TCXO
- 10 MHz clock output
- Three programmable PFI connections
- DC to 50 MHz PFI output range
- 10 ns synchronized clock resolution
- 10/100/1000 Mb/s Ethernet interface
- Active GPS antenna power output
- PXI and PXI Express hybrid-slot compatibility
- Suitable for distributed measurement systems
PXI-6683H Technical Specifications
| Product Model | PXI-6683H |
|---|---|
| Part Number | 782110-02 |
| Product Type | PXI timing and synchronization module |
| Time References | GPS, IEEE 1588 and IRIG-B |
| Onboard Oscillator | 10 MHz TCXO |
| TCXO Accuracy | ±3.5 ppm within one year of calibration adjustment |
| TCXO Long-Term Stability | ±1 ppm per year |
| Clock Output | 10 MHz |
| Clock Output Impedance | 50 Ω nominal |
| Programmable PFI Connections | 3 |
| PFI Output Frequency | DC to 50 MHz |
| Timestamp Minimum Pulse Width | 22 ns |
| Clock Period Resolution | 10 ns |
| Ethernet | 10/100/1000 Mb/s |
| IRIG-B AM Carrier | 1 kHz |
| GPS Synchronization Performance | ±40 ns typical empirical module-to-module result |
| Operating Temperature | 0°C to 55°C |
| Front Connectors | 5 × SMB male and 1 × RJ-45 Ethernet |
| Weight | 172 g |
GPS Time Synchronization
The GPS antenna input receives satellite timing signals and supplies 5 VDC for a compatible active antenna. After acquiring sufficient satellites, the module can align its timebase and generated events with GPS-derived time.
Antenna placement, sky visibility, cable loss and antenna current requirements affect GPS reception. For indoor installations, a rooftop antenna and properly rated coaxial distribution system may be required.
IEEE 1588 Synchronization
The RJ-45 interface allows multiple systems to exchange timing information using IEEE 1588 over Ethernet. Performance depends on the network topology and the behavior of switches between the participating devices.
A direct link or a suitable IEEE 1588-aware switch generally provides better synchronization than a conventional network carrying unpredictable traffic.
IRIG-B and Programmable Triggers
PFI0 can receive IRIG-B DC or amplitude-modulated IRIG-B. PFI1 and PFI2 provide additional programmable trigger and event connections. PFI signals can be routed to PXI trigger lines or used for time-synchronized pulse generation and timestamping.
The input must be placed in the correct IRIG-B operating mode before connecting an AM signal. Applying IRIG-B AM while the terminal is configured as a digital PFI can damage the circuitry.
PXI-6683H Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| PXI-6683H | 782110-02 | GPS, IEEE 1588 and IRIG-B PXI synchronization module |
| Active GPS Antenna | Configuration dependent | Receives GPS signals for the module’s antenna input |
| GPS Antenna Cable | Length dependent | Connects the active antenna to the module |
| SMB Timing Cable | Length dependent | Connects CLKOUT, IRIG-B and PFI signals |
| Shielded Ethernet Cable | Application dependent | Supports IEEE 1588 network communication |
PXI-6683H Applications
- Distributed data acquisition
- GPS-disciplined measurement systems
- IEEE 1588 test networks
- IRIG-B aerospace and defense systems
- Power-grid monitoring
- Structural monitoring
- Phased measurement systems
- Event timestamping
- Multichassis trigger synchronization
- Long-distance measurement coordination
Distributed Measurement Systems
PXI systems installed at different physical locations can align timestamps to a shared time reference. This allows data from separate acquisition systems to be compared on a common timeline.
Aerospace and Defense Timing
IRIG-B support allows the PXI-6683H to integrate with timing systems commonly used in aerospace, defense, telemetry and range applications.
PXI-6683H Installation Workflow
Step 1: Install NI-Sync
Install a compatible NI-Sync driver and PXI Platform Services on the system controller.
Step 2: Install the Module
Power down the chassis and install the PXI-6683H in a compatible PXI or PXI Express hybrid slot.
Step 3: Connect the Time Reference
Connect the GPS antenna, IEEE 1588 Ethernet network or IRIG-B source selected for the application.
Step 4: Configure the Time Source
Use NI-Sync to select the synchronization reference, configure PFI directions and specify the required clock or trigger routing.
Step 5: Confirm Synchronization Status
Monitor the GPS and IEEE 1588 LEDs and verify that software reports the expected synchronization state before recording critical data.
PXI-6683H Troubleshooting
The GPS receiver does not synchronize
Check antenna placement, connector condition, cable loss and active-antenna compatibility. Confirm that the antenna has an adequate view of the sky.
IEEE 1588 synchronization is unstable
Reduce unpredictable network traffic and verify switch compatibility. A direct Ethernet connection can help determine whether the network infrastructure is introducing delay variation.
IRIG-B is not decoded
Confirm the IRIG-B format, signal amplitude, carrier frequency and PFI0 configuration. Ensure that AM and DC modes have not been interchanged.
A generated trigger does not reach another module
Check the selected PXI trigger line, route direction and resource reservation. Verify that another module has not already reserved the same backplane trigger.
The expected CLKIN connector is missing
The PXI-6683H does not provide the external CLKIN connector found on the PXI-6683. Select the correct model according to the required clock-routing architecture.
PXI-6683H Comparison
| Model | Timing Features | Best Suited For |
|---|---|---|
| PXI-6683H | GPS, IEEE 1588, IRIG-B, TCXO | Hybrid-slot distributed synchronization |
| PXI-6683 | GPS, IEEE 1588, IRIG-B and CLKIN | Systems requiring external 10 MHz clock input |
| PXIe-6674T | High-performance clock and trigger routing | Low-jitter PXI Express synchronization |
| PXI-6682 | Earlier GPS and IEEE 1588 synchronization | Maintaining legacy PXI timing systems |
PXI-6683H Frequently Asked Questions
Which time references does the PXI-6683H support?
It supports GPS, IEEE 1588 and IRIG-B time synchronization.
Does it have a GPS receiver?
Yes. The module includes a GPS receiver and powers a compatible active antenna through the antenna connector.
Does the PXI-6683H have CLKIN?
No. It provides CLKOUT but does not include the external CLKIN connector available on the PXI-6683.
Which driver is required?
The module is configured and controlled using NI-Sync.
Can it timestamp external events?
Yes. Its programmable PFI connections can timestamp compatible external signals and generate synchronized events.
Request a Quote for the PXI-6683H
Contact us for availability and project pricing for the PXI-6683H synchronization module, part number 782110-02. We can also help identify GPS antennas, SMB timing cables and related PXI timing modules.
