SPUSI2/NOPB National Semiconductor, SPUSI2/NOPB Datasheet - Page 17

• Manufacturer Part Number: SPUSI2/NOPB
• Description: BOARD EVAL DATA CAPTURE BOARD
• Manufacturer: National Semiconductor

Specifications of SPUSI2/NOPB

• Main Purpose: Interface, Data Capture
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: WEBENCH® Sensor Designer Boards
• Primary Attributes: USB Interface Dongle II
• Secondary Attributes: SPI Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: SPUSI2

6.1.1 Channel Code.
the number of bits supported by the board sensor. The user may select to reduce the
resolution to evaluate the computations with a lower resolution. The user may also select
to use the immediate channel code or a sliding average.
6.1.2 Amplifier Out Voltage.
step:
6.1.3 Amplifier In Voltage.
6.1.4 Sensor Reading.
one of the following three methods. Calculations for some boards may be more complex
and involve data from other channels.
6.1.5 Theoretical mode.
corresponding to the ampIn in a device specific lookup table.
6.1.6 End Point Calibration Mode.
this document, the following equation is used:
subsequent use.
6.1.7 Computational Calibration Mode.
device sensitivity:
calibrated (versus theoretical) menu selection.
refOffset
All measurements begin with a channel code consisting of the ADC resolution,
The channel code is used to compute the AmpOut voltage using this equation:
For thermocouple boards with difference amplifiers there is an additional
The ampOut voltage can be used to compuate the ampIn voltage:
For thermocouple boards with NonInverting amplifiers there is an additional step:
The final computational step determines the sensor input value using variations of
For the theoretical computational mode this involves merely looking up the value
For the end point calibrated mode, explained in detail in the Calibration section of
Once calibrated, the values may be saved and reloaded by the startup script for
The sensor value may also be computed without an end point calibration using the
sensorIn = ampIn / Sensitivity
This is not really a calibrated mode, but defined as such here as it is a part of the
ampOut = chCode * Vref * k * milliConversion / (adcRes - RThermCode) +
ampOut = ampOut – Level Shift
ampIn = ampOut / (ampGainValue * Rf * Rpy * milliConversion)
ampIn = ampIn – Level Shift
sensorIn = chCode * slope + intercept