NI 9219 Calibration Procedure
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© National Instruments Corporation
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37
Full-Bridge Accuracy Adjustment
Complete the following steps to adjust the full-bridge accuracy of the NI 9219.
1.
Connect the NI 9219 to DMM1 as shown in Figure 14.
2.
Adjust the NI 9219 Full-Bridge accuracy.
a.
Initialize a calibration session on the NI 9219. The default password is
NI
.
b.
Call and configure the NI 9219 setup calibration function, to place the channel in RTD
mode, according to Table 41.
c.
Input the external temperature in degrees Celsius.
d.
Call the NI 9219 get C Series adjustment points function to obtain an array of
recommended calibration currents for the NI 9219.
e.
Configure DMM1 for a voltage measurement in the 10 V range.
f.
Enable Auto Zero on DMM1.
g.
Acquire a voltage reading with DMM1. Record this value as V
ExcitationModule
.
h.
Set the voltage source to V
ExcitationModule
.
i.
Connect the NI 9219 to DMM1, DMM2, and the voltage source as shown in
Figures 15 or 16 for the appropriate test point value indicated in Table 33. Observe
the following conditions when connecting the equipment to the NI 9219.
•
Connect the leads of DMM1 as close as possible to the terminals on the NI 9219.
•
Connect the HI lead of DMM2 as close as possible to the same point that the HI
lead of the NI 9219 connects to the resistor network.
•
Connect the LO lead of DMM2 as close as possible to the EX– terminal of the NI
9219.
j.
Configure DMM1 for a voltage measurement in the 10 V range.
k.
Enable Auto Zero on DMM1.
l.
Configure DMM2 for a voltage measurement in the 1 V range.
m. Enable Auto Zero on DMM2.
n.
Acquire voltage measurements with both DMMs. Perform the following calculation
using the two DMM measurements.
o.
Call and configure the NI 9219 adjustment function according to Table 52.
Table 51.
Setup Configuration for Full-Bridge Accuracy Adjustment
Min
(mV/V)
Max
(mV/V)
Physical
Channels
Measurement
Type
Bridge
Configuration
-0.5
0.5
cDAQMod8/ai
x
Bridge
Full-Bridge
Ratio
ref
V
DMM
2
V
DMM
1
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