NI 9219 Calibration Procedure
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© National Instruments Corporation
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17
f.
Clear the task.
5.
Perform the following calculation using the recorded
Ω
ref
and
Ω
channel
values.
6.
Compare the calculation result to the Upper Limit and Lower Limit values in Table 19.
Note
The test limits listed in Table 19 are derived using the values in Table 53.
7.
Disconnect the resistor from the device.
8.
Repeat steps 1 through 7 for all test points on the NI 9219.
9.
Repeat steps 1 through 8 for all channels on the NI 9219.
4-Wire RTD Accuracy Verification
Complete the following steps to verify the 4-wire RTD accuracy of an NI 9219.
1.
Connect the NI 9219 to the resistor and the DMM as shown in Figure 7. Connect the sense
leads of the DMM as close as possible to the same point that the sense leads of the NI 9219
(HI and LO) connect to the resistor to ensure that the DMM reference measurements
include the same lead wire resistance as the NI 9219 4-wire measurements.
Figure 7.
4-Wire RTD Accuracy Verification Connections to the NI 9219
Table 19.
NI 9219 Verification Test Limits for 4-Wire Resistance Accuracy
Mode
Range
Test Point
1
–
Year Limits
Min
(
Ω
)
Max
(k
Ω
)
Location
Value
Lower Limit
(
Ω
)
Upper Limit
(
Ω
)
4-Wire
Resistance 1
k
Ω
0
1.05
Max
845
Ω
±1%
–1.15
1.15
Min
20
Ω
±5%
–0.50
0.50
4-Wire
Resistance 10
k
Ω
0
10.5
Max
8450
Ω
±1%
–7.20
7.20
Min
20
Ω
±5%
–0.64
0.64
Accuracy
Ω
channel
Ω
ref
–
=
R
TestPoint
Ω
HI
LO
NI 9219
MM
Ω
S
EN
S
E
HI
LO
EX+ (3)
HI (4)
EX– (5)
LO (6)
Ch
x