National Instruments NI 4495, Процедура калибровки, Страница: 19 / 22

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NI 449
x
Calibration Procedure
3. Configure the calibrator to output a tone with the amplitude and frequency listed in the 0 dB
gain row of Table 19.
4. Perform the AI AC coupled calibration adjustment by selecting the DAQmx Adjust DSA
AI Calibration With Gain and Coupling VI from the DAQmx Adjust DSA AI Calibration
Polymorphic VI, as shown below. The reference voltage parameter is set to the applied
calibrator output voltage amplitude. The gain parameter is set to the value of the device gain
setting being calibrated, where 0, for example, represents 0 dB. The coupling parameter is
set to AC.
5. Repeat steps 3 and 4 for each gain setting that your device supports. Refer to Table 6 for the
gain settings supported by NI 449x devices. When performing step 3, adjust the output of
the calibrator based on the amplitude and frequency in Table 19. When performing step 4,
adjust the gain and reference voltage parameters appropriately.
6. Connect the output of the isolated voltage source to all input channels on the device, using
the BNC T-connectors to split the signal in a tree formation to all the inputs. Connect the
digital multimeter (voltage function) in parallel with the voltage source output.
Table 19. Calibrator Output for AI AC Coupled Calibration Adjustment on
NI 4492/4497/4499
Device Gain
Calibrator Output
Amplitude (V
rms
) Frequency (Hz)
0 dB 6.36 1000
10 dB 2.012 1000
20 dB 0.636 1000
30 dB 0.201 1000
LabVIEW Block Diagram NI-DAQmx Function Call
Call
DAQmxAdjustDSAAICalWithGainAndC
oupling
with the following parameters:
calHandle
:
myCalHandle
referenceVoltage
:
6.36
gain
: 0.0
coupling
: DAQmx_Val_AC