NI USB-443x Calibration Procedure
12
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8.
Repeat steps 1 through 7. In step 3, set every element in the array to a value of –3.15 instead of
3.15. Compare the result to the limits in Table 13.
Timebase Frequency Accuracy Verification
This section describes the process used to verify the frequency accuracy of the timebase on
NI USB-443
x
devices. All analog input and output channels on a single device use the same timebase
circuitry. Therefore, you only need to verify the timebase accuracy on one channel.
Complete the following steps to verify the timebase accuracy:
1.
Connect the function generator to the channel being verified on the device.
2.
Configure the function generator to generate a 10 kHz sine wave with an amplitude of 9 V
pk
and
no DC offset.
3.
Create and configure an AI voltage task on the NI USB-443
x
as shown in Table 14.
4.
Acquire readings with the NI USB-443
x
.
Table 13.
AO Gain Limits for NI USB-4431
Device Output Amplitude
(VDC)
Device Input Amplitude
(One Year Limits)
Min (V)
Max (V)
3.15
3.1437
3.1563
–3.15
–3.1563
–3.1437
Table 14.
Timebase Frequency Accuracy Verification Configuration for NI USB-443
x
Configuration
Value
Minimum value
–10.0
Maximum value
10.0
Terminal configuration
Pseudodifferential
Acquisition mode
Finite number of samples
Rate
40000.0
Samples per channel
*
2,560,000
Coupling
DC
Physical channel
Dev_name/ai
x
†
*
The read timeout must be greater than 64 seconds.
†
Dev_name is the name shown for the NI USB-443
x
in MAX.
x
refers to the channel number.
