©
National Instruments Corporation
7
NI 9219 Calibration Procedure
2.
Set the source to the appropriate test point value indicated in Table 5. Use the smallest available
range needed to source each test point. Using a range larger than necessary creates unwanted
additional noise.
3.
Configure the DMM for a voltage measurement in the lowest appropriate range according to the
test point from Table 5.
4.
Enable Auto Zero on the DMM.
5.
Acquire a voltage reading with the DMM. Record this measurement as V
ref
.
6.
Create an AI voltage channel on the NI 9219. Configure the channel according to Table 4.
7.
Acquire 20 voltage readings with the NI 9219. Record the average of the readings as V
channel
.
8.
Perform the following calculation using the recorded V
ref
and V
channel
values.
9.
Compare the calculation result to the Upper Limit and Lower Limit values in Table 5.
Table 4.
NI 9219 Configuration for Voltage Accuracy Verification
Measurement
Type
Min (V)
Max (V)
ADC Timing
Mode
Sample Timing
Type
Voltage
–60
60
High Resolution
On Demand
–15
15
–4
4
–1
1
–0.125
0.125
Table 5.
NI 9219 Verification Test Limits for Voltage Accuracy
Range
Test Point
1
–
Year Limits
Minimum
(V)
Maximum
(V)
Location
Value (V)
Lower Limit
(V)
Upper Limit
(V)
–60
60
Max
48
–0.03670
0.03670
Mid
0.0
–0.00100
0.00100
Min
–48
–0.03670
0.03670
–15
15
Max
12
–0.00980
0.00980
Mid
0.0
–0.00080
0.00080
Min
–12
–0.00980
0.00980
–4
4
Max
3.2
–0.00300
0.00300
Mid
0.0
–0.00060
0.00060
Min
–3.2
–0.00300
0.00300
Accuracy
V
channel
V
ref
–
=
