While most PXI devices can inherently use the PXI Trig lines, functionality can be added to the system by using a Timing and Synchronization module. Timing and Synchronization cards can add the following functionality to your system:
Trace-length Matched Trigger Lines
In a PXI chassis, a single slot is designated as the system timing slot. This slot has dedicated equal-length trigger lines between the system timing slot and the remaining peripheral slots, known as star trigger lines. Because star trigger lines are equal-length, a trigger being routed from the system timing slot on the star trigger lines will have less skew between the modules receiving the trigger.
Ability to Synchronize Multiple Chassis
By using a Timing and Synchronization module, a system can import a clock or triggers from external systems. This can be useful when trying to synchronize multiple chassis together; the Timing and Synchronization module in the master chassis exports its clock and back plane trigger lines to the slave chassis.
Additionally, some Timing and Synchronization cards allow for synchronization to network sources such as GPS and IRIG-B. Depending on the system, this may also require a MXI Expansion controller. For more information on how to synchronize multiple systems using Timing and Synchronization, please check the Related Links section below.
More Accurate Clock Source
Many Timing and Synchronization cards have an onboard oscillator with lower jitter specifications than the oscillator onboard the PXI chassis. If an application requires a highly accurate clock, consider adding a Timing and Synchronization module to the system and use it to overwrite the clock on the backplane of the chassis.
For more information about how to implement Timing and Synchronization functionality, view the help file for NI-Sync.