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NI VirtualBench Calibration Procedure
3.
—Perform an external adjustment of the instrument that
adjusts the calibration constants with respect to standards of known values.
4.
DC Power Supply Re-Verification
—Repeat the verification procedure to ensure that the
instrument is operating within its specifications after adjustment.
These steps are described in more detail in the following sections.
Note
If you are calibrating both the DMM and the DC power supply, the DMM
must be calibrated first.
DC Power Supply Test Equipment
Table 19 lists the equipment recommended for the DC power supply performance verification
and adjustment procedures. If the recommended equipment is not available, select a substitute
using the requirements listed in the table.
DC Power Supply Test Conditions
Follow these guidelines to optimize the equipment and the environment during calibration:
•
Keep connections to the device as short as possible. Long cables and wires act as antennae,
picking up noise that can affect measurements.
•
Use a USB connection between the PC and VirtualBench.
•
Verify that all connections to the device, including front panel connections, are secure.
•
Use shielded copper wire for all cable connections. Use twisted-pair, shielded wire to
reduce measurement error in noisy environments.
•
Keep relative humidity between 10% and 80% noncondensing.
•
Allow a warm up time of at least 30 minutes to ensure that the VirtualBench is at a stable
operating temperature.
Table 19.
Recommended Equipment
Equipment
Recommended
Model
Minimum Requirements
Digital multimeter
(DMM)
NI PXI-4071
DC V accuracy: 21 ppm at 25 V
DC input impedance: ≥1 GΩ
DC A accuracy: 310 ppm at 1 A, 460 ppm
at 2 A
Cabling wire
—
18 AWG to 22 AWG. Twisted pair, shielded
cabling wire is recommended