# Synchronizing Analysis with Acquired Data in SCPI Programs

Migration Guide

- Migration Guide
- SCPI Differences
- SCPI Similarities
- SCPI Command Subsystem Comparison
- SCPI Programming Tools
- Setting Up the Oscilloscope in SCPI Programs
- Synchronizing Analysis with Acquired Data in SCPI Programs
- Querying Measurement Results
- Querying Waveform Data
- Waveform Load/Save Format Support
- Debugging SCPI Programs
- Example Programs for Common Oscilloscope Tasks, Old vs. New

When acquisitions are running, setting changes will interrupt and restart acquisition-analysis cycles, making it unclear whether analysis happens on old or new data. Or, depending on the setting change, there may be no data for analysis. So, when acquisitions are running, it is impossible to know whether analysis results are synchronized with the intended data.

To properly synchronize analysis with acquired data, it is important for acquisitions to be stopped (`:ACQuire:STOP`), the display to be cleared (`:ACQuire:CDISplay`), and for the oscilloscope to be set up before making a desired number of acquisitions and analyzing the captured data.

From SCPI, there are a couple ways to make acquisitions that can be properly synchronized:

- Single (`:ACQuire:SINGle`).
- Acquisition Limit Test configured for N waveforms (`:ACQuire:RUN` within `:LTESt:ACQuire` commands).

`:ACQuire:SINGle` and `:ACQuire:RUN` within `:LTESt:ACQuire` commands are overlapped commands that require a following `*OPC?` to synchronize properly. The `*OPC?` query does not return in these cases until acquisitions are complete.

Overlapped commands are commands that return control to the program before they are complete (see Sequential and Overlapped Commands). In Infiniium 2026, there are relatively few overlapped commands as compared to earlier Infiniium. The best way to know whether a command is overlapped is to perform the operation in the GUI with the SCPI Recorder recording. The SCPI Recorder will automatically insert `*OPC?` queries after overlapped commands. These are the only places the `*OPC?` query is useful. For a list of overlapped commands, see *OPC (Operation Complete).