CTA Integration with External Systems 3 — Questions and Answers
Question 1: What is the role of the 'IVI Compliance Package' when integrating IVI-class instrument drivers with TestStand?
- It replaces the need for VISA entirely
- It provides standardized driver interfaces enabling interchangeable instrument control (Correct answer)
- It converts SCPI commands to NI-DAQmx tasks
- It installs TestStand step types for oscilloscopes only
Correct answer: It provides standardized driver interfaces enabling interchangeable instrument control
The IVI Compliance Package installs IVI-class driver interfaces that standardize instrument control, allowing TestStand sequences to swap instruments without code changes.
Question 2: In TestStand, when using the 'Batch Synchronization' model with external systems, what event signals all UUTs to proceed past a synchronization point?
- A semaphore release by the last UUT to arrive (Correct answer)
- A master sequence calling Engine.FireEvent()
- The operator pressing a Continue button on the operator interface
- A hardware trigger on the PXI backplane
Correct answer: A semaphore release by the last UUT to arrive
In Batch Synchronization, the last UUT thread to arrive at the sync point releases the semaphore, unblocking all waiting UUT threads simultaneously.
Question 3: Which TestStand database step type is used to log test results to an external SQL database without writing custom SQL?
- Database Logging step using NI Database Connectivity Toolkit
- Schema-mapped Database Log step using TestStand's built-in DB logging (Correct answer)
- LabSQL step calling stored procedures
- ODBC Direct Query step
Correct answer: Schema-mapped Database Log step using TestStand's built-in DB logging
TestStand's built-in Database Logging schema maps result properties to table columns automatically, requiring only an ODBC connection string and no custom SQL.
Question 4: When a TestStand sequence calls an external web service using the LabVIEW HTTP VIs, what must be configured in the sequence to handle the asynchronous HTTP response?
- A callback step referencing the response event
- A Wait for HTTP Response step or polling loop checking the operation handle (Correct answer)
- A TestStand Synchronization semaphore set by the HTTP VI
- An ActiveX event listener registered on the HTTP adapter
Correct answer: A Wait for HTTP Response step or polling loop checking the operation handle
Asynchronous HTTP calls return an operation handle; the sequence must poll or call a Wait step on that handle to retrieve the response before proceeding.
Question 5: Which TestStand configuration file defines the mapping between result property names and external database column names?
- TestStand.ini
- ResultSchema.xsd
- TestStandDatabase.mdb schema tables
- The Database Schema file (.dbschema or .xsd) referenced in the result list (Correct answer)
Correct answer: The Database Schema file (.dbschema or .xsd) referenced in the result list
The .dbschema or .xsd schema file referenced by the TestStand result list controls how test result properties map to database table columns.
Question 6: In TestStand, what is the correct way to ensure an external shared library (DLL) is unloaded and reloaded between test runs to reset its global state?
- Set the DLL load option to 'Release when sequence is idle' in the DLL adapter (Correct answer)
- Call FreeLibrary() from a LabVIEW step before each run
- Use the 'Load DLL once per test run' option in the module tab
- Restart the TestStand Engine between runs using the API
Correct answer: Set the DLL load option to 'Release when sequence is idle' in the DLL adapter
Setting 'Release when sequence is idle' in the DLL adapter ensures TestStand unloads the DLL when no sequence is running, resetting its global state for the next run.
Question 7: When integrating TestStand with LabVIEW using the LabVIEW adapter, what happens if the called VI's connector pane parameters do not match the step's parameter mapping?
- TestStand silently ignores unmatched parameters
- TestStand throws a run-time error indicating parameter mismatch (Correct answer)
- The VI is called with default values for unmatched inputs
- TestStand automatically remaps parameters by data type
Correct answer: TestStand throws a run-time error indicating parameter mismatch
A connector pane mismatch between the VI and the step's parameter mapping causes a run-time error in TestStand, stopping execution until the mapping is corrected.
CTA Integration with External Systems 3
What is the role of the 'IVI Compliance Package' when integrating IVI-class instrument drivers with TestStand?