National Instruments Deterministic Ethernet Expansion Chassis NI 9144 - Manual (Page 58)

NI 9144 User Guide and Specifications 58 ni.com
NI 9237 Calibration Data
The NI 9237 has four channels. Each channel has an associated LSB
weight, which is the number of volts per bit, and an offset, which is the
number of volts per bit measured when the inputs are grounded.
Note LSB weight is referred to as Gain in the object dictionary.
The calibration data is stored in a U16 array, though each Offset field
(subindex 1, 3, 5, and so on) should be interpreted as a signed value.
Use the calibration coefficients with the following equation to generate
corrected data:
NI 9229/9239
Table 53. NI 9237 Scan List Format
Coefficient Representation Units
LSB Weight Unsigned pV/LSB
Offset Signed nV
Table 54. NI 9229/9239 Vendor Configuration Extensions
Index Sub Type R/W Description
0x2002 0 U32 R/W Configure ADC,
default = 0x06
0x2100 0 ARR:U32 Calibration = 16
1 R Ch0 Offset
2 R Ch0 Gain
3 R Ch1 Offset
... ...
8 R Ch3 Gain
9 R External Ch0
Offset
... ...
V
corrected
V
raw
( ) V
raw
bits ( )∗ LSB
weight
pV
bits
---------
⎝ ⎠
⎛ ⎞∗10 13 –
V
pV
-------
⎝ ⎠
⎛ ⎞
⎩ ⎭
⎨ ⎬
⎧ ⎫
Offset pV ( )∗10 8 –
V
nV
-------
⎝ ⎠
⎛ ⎞
⎭
⎬
⎫
– =