© National Instruments Corporation 31 NI 9144 User Guide and Specifications
3. Select the 32-bit offset value (to be interpreted as a signed int) for a
particular range.
4. Use the above final coefficients and complete the following steps in the
quadratic equation to convert raw 16-bit data into scaled volts:
a. a0 = (f64(a0) * rangeGain) + rangeOffset
b. a1 = f64(a1) * rangeGain
c. a2 = f64(a2) * rangeGain
d. a3 = f64(a3) * rangeGain
5. Use the following formula with a3–a0 to obtain the scaled 16-bit value
in Volts.
x =signed un-scaled 16-bit data read from device:
Scaled 16-bit signed data in Volts = a3*x3 + a2*x2 + a1*x + a0
It is also possible to decode the raw data using only the offset and gain
values. For more information, refer to the NI 9201/9221 section of this
guide.
NI 9211

NI 9211 Scan List

The scan list is a simple list of channels to convert, in order. The NI 9211
has six channels total that can be measured:
0..3: Four input channels (always measured in a ±80 mV range)
4: One cold junction channel (always measured in a ±2.5 V range)
5: One auto zero channel (always measured in a ±80 mV range)
Table 18. NI 9211 Vendor Configuration Extensions
Index Sub Type R/W Description
0x2001 0 ARR:U32 Scan List = 7
1 R Channels to
Convert = 1..6,
default = 6
2..7 R/W Channel Number