©
National Instruments Corporation
23
NI 5421/5441 Calibration Procedure
21. Measure the DC voltage out of the NI 5421/5441. This is the
Measured
Negative Full-Scale Value
.
22. Determine the error for negative full scale using the following formula:
Error Negative Full-Scale
=
(
Measured Negative Full-Scale Value
) – (
Ideal Negative Full-Scale Value
)
Compare this error to the
Published Spec
or the
Calibration Test Limit
.
23. Call
niFgen_AbortGeneration
(niFgen Abort Generation VI) to
abort the waveform generation using the following parameter:
•
vi
: The session handle returned from
niFgen_init
24. If any of the errors are greater than the
Calibration Test Limit
, perform
an external adjustment.
Verifying the Main Analog Path Offset
To verify the offset of the NI 5421/5441 main analog path, complete the
following steps:
1.
Create an array of waveform samples for the mid-scale DC waveform
(0 VDC). This array should contain 500 samples with each sample
having the value
0.0
(representation: double).
2.
Call
niFgen_CreateArbWaveform
(niFgen Create Arbitrary
Waveform VI) using the following parameters:
•
vi
: The session handle returned from
niFgen_init
•
wfmSize
: The size in samples (
500
) of the waveform that you
created in step 1
•
wfmData
: The array of waveform samples that you created in
step 1
•
wfmHandle
: The variable passed by reference through this
parameter receives the value (waveform handle) that identifies
the waveform created by this function (mid-scale handle).
3.
Call
niFgen_SetAttributeViInt32
to choose the mid-scale
handle DC waveform (niFgen property node:
Arbitrary Waveform
Output»Arbitrary Waveform Handle
) using the following
parameters:
•
vi
: The session handle returned from
niFgen_init
•
channelName
:
"0"
•
attributeID
:
NIFGEN_ATTR_ARB_WAVEFORM_HANDLE
•
value
: The
wfmHandle
from step 2 (mid-scale handle)
Repeat steps 4 through 14 for each of the 24 iterations listed in Table 5,
changing the
Ideal Positive Offset
,
Ideal Negative Offset
, and
Gain
values
for each iteration.
