NI-9381 Vendor Configuration Extensions

The following table lists the vendor configuration extensions for the NI-9381.

Table 107. NI-9381 Vendor Configuration Extensions
Index Sub Type R/W Description
0x2100 0 U32 R/W Digital Channel Direction Control, default = 0
0 ARR:U16 — Calibration = 64
1 R AI0 Offset
2 R AI0 Gain
... — —
15 R AI7 Offset
16 R AI7 Gain
17 R AO0 Offset
18 R AO0 Gain
... — —
31 R AO7 Offset
32 R AO7 Gain
33 R External AI0 Offset
... — —

NI-9381 Calibration Data

The NI-9381 has either input channels or output channels with a nominal range of 0 V to 5 V. 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 NI-9381 EEPROM stores two constants for each channel. The host takes the constants and adjusts the raw data in calibrated data. The calibration data is stored in a U16 array.

Table 108. NI-9381 Calibration Coefficients
Coefficient Representation Units
LSB Weight Unsigned 100 nV/LSB
Offset Signed 10 µV

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

Figure 34. NI-9381 Corrected Data Equation
V corrected = Raw ⁢ × ( LSB weight × 10 − 7 ) + Offset × 10 − 5 V corrected = Raw ⁢ × ( LSB weight × 10 − 7 ) + Offset × 10 − 5

where Raw represents raw data returned by the NI-9381 and Vcorrected represents the corrected voltage value

NI-9381 Digital Channel Direction Control

Table 109. NI-9381 Digital Channel Direction Control
Bits Field
3

0: data bit as input

1: data bit as output

2
1
0