Set the Calibration Mode to Calibrated in the C Series Module Properties dialog box for the NI 9262/NI 9263/NI 9264/NI 9269 if you want the FPGA I/O Node to accept fixed-point data in units of volts when writing to the module.

If you set the Calibration Mode to Raw, the FPGA I/O Node accepts only binary values when writing to the module. Convert output voltage values to binary values before you write them to the module. Convert these values in the host VI.

Using an Equation to Convert Voltage to Binary

You can use the following equation in the host VI to convert the analog output values to binary values:

Binary Value = (Voltage Value × 109 – Offset) ÷ LSB Weight

Where
  • Binary Value is the value you write to the FPGA I/O Node
  • Voltage Value is the voltage in V that you want the channel to output
  • Offset is the value returned by the Offset property
  • LSB Weight is the value returned by the LSB Weight property.

NI recommends using calibrated values for analog output. To convert calibrated voltage values, use the FPGA I/O Property Node to read the LSB Weight and Offset properties.

If you do not want to read the LSB Weight and Offset values from the module, convert uncalibrated voltage values by using the following values for Offset and LSB Weight:

Offset = 0

LSB Weight = Typical Output Span ÷ 2DAC Resolution × 109

Where
  • Typical Output Span is 21.4 V for the NI 9263, 21 V for the NI 9264, and 20.98 V for the NI 9269.
  • DAC Resolution is the DAC resolution of the module. Refer to the module hardware documentation for this value.