Welcome to the LxiSync Interface Reference
This section contains the reference material for the LxiSync APIs. These APIs are implemented by the driver for all Class A/B LXI devices. They provide control of the event capabilities of LXI including configuring the trigger and its sources and configuring how events are transmitted to other devices from within the instrument. This includes three distinct trigger mechanisms:
- Wired Trigger – LXI devices have a wired trigger bus. This is a physical connection that is routed between each module. The LXI Wired Trigger bus provides eight parallel trigger lines. Each of the eight trigger lines can be used in either a driven mode or in a wired-OR mode. In driven mode a single device drives the trigger line either high or low, and any device on the bus can receive that signal. In wired-OR mode, the signal on the trigger line represents the logical OR of each of the devices that is currently enabled to drive the line.
- LAN Triggers – LXI defines two protocols for issuing triggers over the LAN. One is based on UDP, and is transmitted to multiple receivers (multi-cast). The other is based on TCP and is transmitted to a single receiver.
- Alarms – Accurate alarm triggers are enabled by the IEEE 1588 synchronized real-time clock in Class A and B LXI modules. The LxiSync API provides a way to set a specific time at which an event (for instance, a trigger) will occur. Since each device in the system has synchronized clocks, this mechanism can be used to take simultaneous, or other carefully synchronized measurements in a system.
The LxiSync Interface provides ways to control each of these clock sources and how they are combined through both Arm and Trigger interfaces to ultimately enable an action to take place in the instrument.
The Event subsystem controls when, and how, various events that are relevant to the particular instrument are transmitted to other instruments. For instance, a LAN trigger may be sent when a signal generator has completed a sweep.
Finally, the LxiSync API provides the necessary functions for interaction with the IEEE 1588 clock in an instrument.
The LxiSync API is not an instrument class. Typically, instruments that logically belong to a class that is defined by IVI will implement the class API and the LxiSync API. The LxiSync API does not include the APIs for accessing the conventional trigger mechanisms since these are already in the existing classes. The key link between the two APIs is the trigger source, which is where the final source of the trigger is specified. Class compliant applications will use the Trigger Source property to set the trigger to an LXI based source, and use the trigger source property (if it exists) in the class API to access other sources.