The LXI IVI programming model for synchronization and triggering

The LXI Standard provides three synchronization and trigger methodologies in addition to what system designers are familiar with on rack and stack instruments: 1) A high speed L VDS trigger bus that is eight lanes wide. 2) LAN events and triggers which can be used in place of wires or in addition to them. 3) Very accurate absolute time keeping, time stamping, and time based triggers using IEEE 1588 clocks. An IVI programming model for controlling these methodologies is explored and an example measurement scenario presented based on the use of synthetic instruments working together to make a stimulus-response measurement. The sample code presented shows the ease with which a test engineer can switch between the LXI trigger lines and the equivalent LAN trigger mechanism. Logic models and a state machine example are presented describing necessary arming, triggering, and event generation logic. Tradeoffs between hardware and software implementations are outlined and all of these models are wrapped together to illustrate what is needed in an LXI device to use these capabilities