©
National Instruments Corporation
19
NI 9219 Calibration Procedure
16. Scale the data by using the formula below to change the unscaled data into
.
where
range
max
is the maximum value for the selected range in Table 19.
17. Perform the following calculation using the recorded
ref
and
channel
values.
18. Compare the calculation result to the Upper Limit and Lower Limit values in Table 19.
Table 19.
NI 9219 Verification Test Limits for 3-Wire RTD Accuracy
19. Clear the acquisition.
20. Disconnect the resistor from the device.
21. Repeat steps 1 through 20 for all test points and channels on the NI 9219. NI recommends that you
verify the values for all the iterations listed in Table 19 for each channel, but you can save time by
verifying only the values and channels used in your application.
Half-Bridge Accuracy Verification
Complete the following steps to verify the half-bridge accuracy of an NI 9219.
1.
Connect the NI 9219 to DMM1 as shown in Figure 11.
Figure 11.
Half-Bridge Accuracy Verification Connections to the NI 9219 (Configuration 1)
Mode
Range
Test Point
1
–
Year Limits
Min (
)
Max (
)
Location
Value
Lower Limit (
)
Upper Limit (
)
3-Wire
RTD
Pt1000
0
5050
Max
4020
±1%
–3.86
3.86
Min
20
±5%
–0.62
0.62
3-Wire
RTD Pt100
0
505
Max
402
±1%
–0.80
0.80
Min
4.99
±5%
–0.48
0.48
channel
data
unscaled
2
24
-----------------------------
range
max
=
Accuracy
channel
ref
–
=
NI 9219
HI
V
LO
DMM1
EX+ (3)
HI (4)
EX– (5)
Ch
x
