NI 9219 Calibration Procedure
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© National Instruments Corporation
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21
6.
Acquire and average samples.
a.
Create an AI RTD task on the NI 9219 according to Table 23.
b.
Configure the AI RTD task timing according to Table 15.
c.
Start the task.
d.
Acquire 20 unscaled I32 3-wire readings with the NI 9219.
e.
Record the average of the readings as data
unscaled
.
f.
Clear the task.
7.
Scale the data by using the formula below to change the unscaled data into
Ω
.
where
range
max
is the maximum value for the selected range in Table 25.
8.
Perform the following calculation using the recorded
Ω
ref
and
Ω
channel
values.
9.
Compare the calculation result to the Upper Limit and Lower Limit values in Table 25.
Table 23.
NI 9219 Configuration for 3-Wire RTD Accuracy Verification
Measurement
Type
Min (°C)
Max
(°C)
Excitation
Source
Excitation
Value
Resistance
Config
r0
*
3-Wire RTD
Pt1000
0
800
Internal
0.0005
3-Wire
1000
3-Wire RTD
Pt100
100
*
RTD nominal resistance at 0 °C.
Table 24.
NI 9219 Timing Configuration
ADC Timing Mode
Sample Timing Type
High Resolution
On Demand
Ω
channel
data
unscaled
2
24
-------------------------------
range
max
×
=
Accuracy
Ω
channel
Ω
ref
–
=