National Instruments Deterministic Ethernet Expansion Chassis NI 9144 - Manual (Page 23)

© National Instruments Corporation 23 NI 9144 User Guide and Specifications
NI 9201/9221 Calibration Data
The NI 9201/9221 modules have eight channels with a nominal range of
±10.53 V and ±62.5 V, respectively. 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 U32 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:
Table 7. NI 9221/9201 Calibration Coefficients
Coefficient Representation Units
LSB Weight Unsigned nV/LSB
Offset Signed nV
V
corrected
V
raw
( ) V
raw
bits ( )∗ LSB
weight
nV
bits
---------
⎝ ⎠
⎛ ⎞∗10 9 –
V
nV
-------
⎝ ⎠
⎛ ⎞
⎩ ⎭
⎨ ⎬
⎧ ⎫
Offset nV ( )∗10 9 –
V
nV
-------
⎝ ⎠
⎛ ⎞
⎩ ⎭
⎨ ⎬
⎧ ⎫
– =