PCI/PXI/CompactPCI analog output (AO) devices. This document does not discuss programming techniques or compiler configuration. The National Instruments DAQmx driver contains help files that have compiler-specific instructions and detailed function explanations. You can add these help files when you install NI-DAQmx on the calibration computer.
AO GND AO EXT REF Calibrator Figure 1. Calibration Connections When performing calibration, National Instruments recommends that you use the following instruments for calibrating an AO device: • Calibrator—Fluke 5700A. If that instrument is unavailable, use a high-precision voltage source that is at least 50 ppm accurate for 12- and 13-bit boards and 10 ppm for 16-bit boards.
These steps are described in detail in the following sections. Because a complete verification of all of the device’s ranges can take some time, you may wish to verify only the ranges of interest to you. Initial Setup NI-DAQmx automatically detects all AO devices. However, for the driver to communicate with the device, it must be configured in NI-DAQmx.
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Table 2. Connecting the DMM to AO <8..31> on the NI 6723 (Continued) Output Channel DMM Positive Input DMM Negative Input AO 27 AO 27 (pin 14) AO GND (pin 48) AO 28 AO 28 (pin 13) AO GND (pin 47) AO 29 AO 29 (pin 46) AO GND (pin 12)
Repeat steps 4 through 8 until all values have been tested. 10. Disconnect the DMM from AO 0, and reconnect it to the next channel, making the connections as shown in Table 1. 11. Repeat steps 4 through 10 until you have verified all channels. 12.
AO Adjustment Procedure Use the AO adjustment procedure to adjust the analog output calibration constants. At the end of each calibration procedure, these new constants are stored in the external calibration area of the EEPROM. These values are password-protected, which prevents the accidental access or modification of any calibration constants adjusted by the metrology laboratory.
AO Device Test Limits The tables in this section list the accuracy specifications to use when verifying and adjusting the NI 671X/672X/673X. The tables display the specifications for both 1-year and 24-hour calibration intervals. The 1-year ranges display the specifications that the devices should meet if it has been one year between calibrations.
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