National Instruments Deterministic Ethernet Expansion Chassis NI 9144 - Manual (Page 59)

© National Instruments Corporation 59 NI 9144 User Guide and Specifications
As a DSA module, the NI 9229/9239 does not synchronize to other
modules and free-runs at its own fixed rate.
For more information, refer to the NI 9233 Configure ADC section of this
document.
Note The NI 9229/9239 does not have the Turbo Bit configuration byte.
NI 9229/9239 Calibration Data
The NI 9229/9239 have four channels with nominal ranges of ±10 V and
±60 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 55. NI 9229/9239 Scan List Format
Coefficient Representation Units
LSB Weight Unsigned pV/LSB
Offset Signed nV
V
corrected
V
raw
( ) V
raw
bits ( )∗ LSB
weight
pV
bits
---------
⎝ ⎠
⎛ ⎞∗10 12 –
V
pV
-------
⎝ ⎠
⎛ ⎞
⎩ ⎭
⎨ ⎬
⎧ ⎫
Offset pV ( )∗10 9 –
V
nV
-------
⎝ ⎠
⎛ ⎞
⎭
⎬
⎫
– =