NI 9219 Calibration Procedure
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© National Instruments Corporation
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9
b.
Configure the AI thermocouple task timing according to Table 6.
c.
Start the task.
d.
Acquire 20 unscaled I32 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 volts.
where
range
max
is the maximum value (mV) in Table 7.
8.
Perform the following calculation using the recorded V
ref
and V
channel
values.
9.
Compare the calculation result to the Upper Limit and Lower Limit values in Table 7.
Note
The test limits listed in Table 7 are derived using the values in Table 53.
10. Set the source output to zero.
11. Repeat steps 2 through 10 for all test points on the NI 9219.
12. Repeat steps 2 through 11 for all channels on the NI 9219.
13. Disconnect the source and the DMM from the device.
Table 5.
NI 9219 Configuration for Thermocouple Accuracy Verification
Measurement Type
Minimum (°C)
Maximum (°C)
Thermocouple
0
100
Table 6.
NI 9219 Timing Configuration
ADC Timing Mode
Sample Timing Type
High Resolution
On Demand
Table 7.
NI 9219 Verification Test Limits for Thermocouple Accuracy
Range
Test Point
1
–
Year Limits
Minimum
(mV)
Maximum
(mV)
Location
Value (V)
Lower Limit
(V)
Upper Limit
(V)
–125
125
Max
0.10
–0.000041
0.000041
Min
0.00
–0.000010
0.000010
V
channel
data
unscaled
2
23
-------------------------------
range
max
×
=
Accuracy
V
channel
V
ref
–
=