NI 6703/6704 Calibration Procedure for Traditional NI-DAQ
2
ni.com
External Calibration
External calibration requires a high-precision digital multimeter (DMM)
to measure error on the NI 6703/6704 outputs. The error is then corrected
with a set of calibration constants that adjust the offset and gain of the
16-bit DAC to ensure that the output voltages and currents are within the
device specifications.
Because of the NI 6703/6704 calibration circuitry, the only calibration
adjustment you must make is to the values of the calibration channels to
account for time- or temperature-related drift of the onboard reference.
Equipment and Other Test Requirements
This section describes the equipment, test conditions, documentation, and
software you need to calibrate the NI 6703/6704.
Test Equipment
To calibrate the NI 6703/6704, you need a high-precision DMM that is at
least 10 ppm (0.001%) accurate. NI recommends that you use the
Hewlett-Packard 3458A DMM for calibration.
If you do not have a Hewlett-Packard 3458A DMM, use the accuracy
specifications to select a substitute calibration standard.
If you do not have custom connection hardware, you may need a connector
block such as the NI CB-68 and a cable such as the SH6868-D1. These
components give you easy access to the individual pins on the 68-pin
I/O connector.
Test Conditions
Follow these guidelines to optimize connections and test conditions during
calibration:
•
Keep connections to the NI 6703/6704 short. Long cables and wires
act as antennae, picking up extra noise that can affect measurements.
•
Use shielded copper wire for all cable connections to the device.
Use twisted-pair wire to eliminate noise and thermal offsets.
•
Maintain a temperature between 18 and 28 °C. To operate the module
at a specific temperature outside this range, calibrate the device at that
temperature.
•
Keep relative humidity below 80%.
•
Allow a warm-up time of at least 15 minutes to ensure that the
measurement circuitry is at a stable operating temperature.
