NI-DAQmx checks the timing, triggering, and channel attributes/properties for correctness when the task transitions from the Unverified to the Verified state. You can explicitly perform this transition by calling the Control Task function/VI with Action set to Verify. While NI-DAQmx detects and verifies some invalid values for attributes/properties immediately when you set the attribute/property, NI-DAQmx cannot verify other values immediately because they depend on other attributes/properties and the devices being used. NI-DAQmx checks the value of these attributes/properties during the verify transition and reports any invalid values at that time. If NI-DAQmx finds no invalid values, the task is successfully verified and transitions to the Verified state. Otherwise, it remains in the Unverified state.
In certain cases, NI-DAQmx will coerce the values of attributes/properties when successfully verifying a task rather than generating an error. This is done when the value set on the attribute/property cannot be met exactly as specified and coercing it to a legal value has little functional impact on the task.