SCXI-1104 Calibration Procedure
8
ni.com
12. Read the voltage from the DMM. Record the actual DMM reading,
output2
, and the calibrator output voltage,
voltage2
.
You now have two pairs of data points, (
volt1
,
output1
) and
(
volt2
,
output2
), where
volt
is the calibrator reading and
output
is
the DMM reading.
13. Convert the DMM voltage readings (
output1
and
output2
) to binary
readings (
binary1
and
binary2
) by using one of the following
equations:
For example, using a 12-bit product such as a PCI-MIO-16E-1 and
obtaining a DMM reading of –9.9 V, you would have the following
results:
binary reading
= (–9.9/20)
×
2
12
= –2027.52
14. Record
binary1
with
volt1
and
binary2
with
volt2
for later use.
15. Repeat step 4 through 14 for the remaining channels you want to
adjust.
Adjusting Calibration Constants
Complete the following steps to adjust the calibration constants on your
SCXI-1104:
1.
Call
SCXI_Cal_Constants
to create and store the new calibration
constants in the SCXI-1104 memory. Set the following parameters:
•
SCXIchassisID
—The ID assigned by Measurement &
Automation Explorer
•
ModuleSlot
—1, unless you have installed the module in a
different slot
•
channel
—The channel you want to adjust
•
OpCode
—2
•
calibrationArea
—0
•
rangeCode
—0 (not used for the SCXI-1104)
•
SCXIgain
—0.1
•
DAQboard
—The device number assigned by the Measurement
& Automation Explorer
•
DAQChan
—0
binary reading for 12-bit E Series products (binary)
output
20
-----------------
2
12
×
=
binary reading for 16-bit E Series praducts (binary)
output
20
-----------------
2
16
×
=