National Instruments NI PXI-5422 Benutzerhandbuch

External calibration involves both verification and adjustment. Verification 
is the process of testing the device to ensure that the output accuracy is 
within certain specifications. You can use verification to ensure that the 
adjustment process was successful or to determine if the adjustment 
process needs to be performed.

Adjustment is the process of measuring and compensating for device 
performance to improve the output accuracy. Performing an adjustment 
updates the calibration date, resetting the calibration interval. The device is 
guaranteed to meet or exceed its published specifications for the duration 
of the calibration interval. 

This document provides two sets of test limits for most verification stages, 
the calibration test limits and the published specifications. The calibration 
test limits are more restrictive than the published specifications. If all of 
the output errors determined during verification fall within the calibration 
test limits, the device is guaranteed to meet or exceed its published 
specifications for a full calibration interval (two years). For this reason, 
you must verify against the calibration test limits when performing 
verification after adjustment. 

If all of the output errors determined during verification fall within the 
published specifications, but not within the calibration test limits, the 
device meets its published specifications. However, the device may not 
remain within these specifications for another two years. The device will 
meet published specifications for the rest of the current calibration interval. 

In this case, you can perform an adjustment if you want to improve 
the output accuracy or reset the calibration interval. If some output 
errors determined during verification do not fall within the published 
specifications, you must perform an adjustment to restore the device 
operation to its published specifications.

The Complete Calibration section describes the recommended 
calibration procedure. The 

 section describes 

alternate procedures that allow you to skip adjustment if the device 
already meets its calibration test limits or published specifications.

Performing a complete calibration is the recommended way to guarantee 
that the NI PXI-5422 meets or exceeds its published specifications for a 
two-year calibration interval. At the end of the complete calibration 
procedure, you verify that the output error falls within the calibration test 
limits. Figure 1 shows the programming flow for complete calibration.