Configure Ref Clock
- Updated2023-02-17
- 3 minute(s) read
Configure Ref Clock
Configures the NI-RFSG device Reference Clock.
The Reference Clock ensures that the NI-RFSG devices are operating from a common timebase.
The NI-RFSG device must be in the Configuration state before you call this node.
Inputs/Outputs

error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Default value: No error

ref clock source
Source of the Reference Clock signal.
| Onboard Clock |
Uses the onboard Reference Clock as the clock source. PXIe-5840 with PXIe-5653: Lock to the PXIe-5653 onboard clock. Connect the REF OUT (10 MHz) connector on the PXIe-5653 to the PXIe-5840 REF IN connector. Configure open NI-RFSA sessions to the device to use RefIn for the PXIe-5840 or RefIn2 for the PXIe-5840 with PXIe-5653. |
| RefIn |
Uses the clock signal present at the front panel REF IN connector as the clock source. PXIe-5840 with PXIe-5653: Lock to the signal at the REF IN connector on the associated PXIe-5653. Connect the REF OUT (10 MHz) connector on the PXIe-5653 to the PXIe-5840 REF IN connector. |
| PXI Clock |
Uses the PXI_CLK signal, which is present on the PXI backplane, as the clock source. |
| ClkIn |
Uses the clock signal present at the front panel CLK IN connector as the clock source. |
| RefIn2 |
This value is valid on only the PXIe-5840 with PXIe-5653. NI-RFSG locks the Reference Clock to the clock sourced at the PXIe-5840 REF IN terminal that is already configured by an NI-RFSA session. Connect the PXIe-5840 REF OUT connector to the PXIe-5653 REF IN connector. Configure open NI-RFSA sessions to the device to use RefIn for the PXIe-5840 or Onboard Clock for the PXIe-5840 with PXIe-5653. |
| PXI_ClkMaster |
This value is valid on only the PXIe-5840 with PXIe-5653. NI-RFSA configures the PXIe-5653 to export the Reference Clock, and configures the PXIe-5840 to use PXI_Clk. Connect the PXIe-5653 REF OUT (10 MHz) connector to the PXI chassis REF IN connector for this configuration. For best performance, configure all other devices in the system to use PXI_Clk as the Reference Clock source. |
Default value: Onboard Clock

ref clock rate
Reference Clock rate, in hertz (Hz).
Default value: Auto (-1.0)
Automatic Reference Clock Detection
Specifying the Reference Clock rate value as Auto allows NI-RFSG to either use the default Reference Clock rate for the device or automatically detect the Reference Clock rate, if auto-detection is supported on the device.

session out
Reference to your instrument session passed to the next node.

error out
Error information.
The node produces this output according to standard error behavior.
Hardware Support
This node supports the following hardware:
- PXIe-5644/5645/5646
- PXI/PXIe-5650/5651/5652, PXIe-5653/5654/5654 with PXIe-5696
- PXIe-5673E
- PXIe-5820/5840
Examples
Search within the programming environment to access the following installed examples:
- RFSG Getting Started Single Tone Generation
- RFSG Arbitrary Waveform Generation (Arb)
- RFSG Getting Started Script (Script)
