NI-9229/9239 Vendor Configuration Extensions

The following table lists the vendor configuration extensions for the NI-9229/9239.

Table 94. 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
... — —

As a DSA module, the NI-9229/9239 does not synchronize to other modules and free-runs at its own fixed rate.

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.

Table 77. NI-9229/9239 Scan List Format
Coefficient Representation Units
LSB Weight Unsigned pV/LSB
Offset Signed nV

Use the calibration coefficients with the following equation to generate corrected data.

Figure 19. NI-9229/9239 Corrected Data Equation
V corrected = Raw × ( LSB weight × 10 − 12 ) − Offset × 10 − 9 V corrected = Raw × ( LSB weight × 10 − 12 ) − Offset × 10 − 9

where Raw represents raw data returned by the NI-9229/9239 and Vcorrected represents the corrected voltage value.