NI 9219 Calibration Procedure
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© National Instruments Corporation
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13
c.
Start the task.
d.
Acquire 20 2-wire resistance readings with the NI 9219.
e.
Record the average of the readings as
Ω
channel
.
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 13.
Note
The test limits listed in Table 13 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.
Quarter-Bridge Accuracy Verification
Complete the following steps to verify the quarter-bridge accuracy of an NI 9219.
1.
Connect the NI 9219 to the resistor and the DMM as shown in Figure 5. Observe the
following conditions when connecting the equipment to the NI 9219.
•
Connect the leads of the DMM as close as possible to the terminals on the NI 9219 to
ensure that the DMM reference measurements include the same lead wire resistance
as the NI 9219 quarter-bridge measurement.
•
Secure the spring-terminal connectors to the NI 9219 using the captive screws.
Table 13.
NI 9219 Verification Test Limits for 2-Wire Resistance Accuracy
Mode
Range
Test Point
1–Year Limits
Min (
Ω
)
Max
(
k
Ω
)
Location
Value
Lower Limit
(
Ω
)
Upper Limit
(
Ω
)
2-Wire
Resistance
1 k
Ω
0
1.05
Max
845
Ω
±1%
–1.15
1.15
Min
20
Ω
±5%
–0.50
0.50
2-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
–
=