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NI 9212 Calibration Procedure
CJC Adjustment
Complete the following procedure to adjust the CJC accuracy
of the NI 9212.
1.
Loosen the captive screws and remove the top cover from the NI CAL-9212.
2.
Connect the digital multimeter to the NI CAL-9212, as shown in Figure 5. Ensure that
CJC
x
Input+ and CJC
x
Input- are left unconnected.
Figure 5.
CJC Channel Adjustment Coefficient Acquisition Connections
3.
Reinstall the top cover on the NI CAL-9212.
4.
Connect the NI CAL-9212 to the NI 9212, as shown in Figure 2.
5.
Wait at least 15 seconds for the NI 9212 to settle before proceeding to the next step.
6.
Acquire the adjustment coefficient.
a.
On the digital multimeter, set the range to 10 V.
b.
On the digital multimeter, set the input resistance to greater than 10 G
Ω
.
a.
Take five digital multimeter readings.
b.
Average the digital multimeter readings.
c.
Perform the following calculations to obtain the adjustment coefficient.
7.
Remove the NI CAL-9212 from the NI 9212.
8.
Loosen the captive screws and remove the top cover from the NI CAL-9212.
9.
Connect the calibrator and digital multimeter to the NI CAL-9212, as shown in Figure 6.
Figure 6.
CJC Channel Adjustment Connections
LO
Digit
a
l M
u
ltimeter
NI CAL-9212
GROUND LUG
HI
CJC
x
S
en
s
e –
CJC
x
S
en
s
e +
Adjustment coefficient
2.5
Averaged digital multimeter reading
---------------------------------------------------------------------------------------
=
LO
HI
Digit
a
l M
u
ltimeter
LO
HI
C
a
li
b
r
a
tor
NI CAL-9212
GROUND LUG
CJC
x
S
en
s
e –
CJC
x
S
en
s
e +
CJC
x
Inp
u
t –
CJC
x
Inp
u
t+
