NI 9219 Calibration Procedure
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© National Instruments Corporation
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19
6.
Perform the following calculation using the recorded
Ω
ref
and
Ω
channel
values.
7.
Compare the calculation result to the Upper Limit and Lower Limit values in Table 22.
Note
The test limits listed in Table 22 are derived using the values in Table 53.
8.
Disconnect the resistor from the device.
9.
Repeat steps 1 through 8 for all test points on the NI 9219.
10. Repeat steps 1 through 9 for all channels on the NI 9219.
3-Wire RTD Accuracy Verification
Complete the following steps to verify the 3-Wire RTD accuracy of an NI 9219.
1.
Connect the NI 9219 to the resistor and the DMM as shown in Figure 8. Connect the
Ω
HI
and
Ω
senseHI
leads of the DMM directly to the spring-terminal connector of the NI 9219 and
the
Ω
LO
and the
Ω
senseLO
leads of the DMM as close as possible to the same point where the
LO lead from the NI 9219 connects to the resistor to ensure that the DMM reference
measurements include the same lead wire resistance as the NI 9219 3-wire measurements.
Figure 8.
3-Wire RTD Accuracy Verification Connections to the NI 9219
Table 22.
NI 9219 Verification Test Limits for 4-Wire RTD Accuracy
Mode
Range
Test Point
1
–
Year Limits
Min (
Ω
)
Max (
Ω
)
Location
Value
Lower
Limit (
Ω
)
Upper
Limit (
Ω
)
4–Wire
RTD
Pt1000
0
5050
Max
4020
Ω
±1%
–3.73
3.73
Min
20
Ω
±5%
–0.61
0.61
4–Wire
RTD Pt100
0
505
Max
402
Ω
±1%
–0.79
0.79
Min
4.99
Ω
±5%
–0.48
0.48
Accuracy
Ω
channel
Ω
ref
–
=
R
TestPoint
NI 9219
Ω
HI
LO
DMM
Ω
S
EN
S
E
HI
LO
EX+ (3)
LO (6)
EX– (5)
Ch
x