Solution
This multi-range measuring function is supported by X Series devices.
The following figure shows the X Series Analog Input Circuitry, which is the path the signal goes through when you take a analog input measuring task:
To simply illustrate what does each block do, please refer to the follows:
- I/O Connector—You can connect analog input signals to the MIO X Series device through the I/O connector. The proper way to connect analog input signals depends on the analog input ground-reference settings.
- Mux—Each MIO X Series device has one analog-to-digital converter (ADC). The multiplexers (mux) route one AI channel at a time to the ADC through the NI-PGIA.
- Ground-Reference Settings—The analog input ground-reference settings circuitry selects between differential, referenced single-ended, and non-referenced single-ended input modes. Each AI channel can use a different mode.
- Instrumentation Amplifier (NI-PGIA)—The NI programmable gain instrumentation amplifier (NI-PGIA) is a measurement and instrument class amplifier that minimizes settling times for all input ranges. The NI-PGIA can amplify or attenuate an AI signal to ensure that you use the maximum resolution of the ADC. MIO X Series devices use the NI-PGIA to deliver high accuracy even when sampling multiple channels with small input ranges at fast rates. MIO X Series devices can sample channels in any order, and you can individually program each channel in a sample with a different input range.
- A/D Converter—The analog-to-digital converter (ADC) digitizes the AI signal by converting the analog voltage into a digital number.
- AI FIFO—MIO X Series devices can perform both single and multiple A/D conversions of a fixed or infinite number of samples. A large first-in-first-out (FIFO) buffer holds data during AI acquisitions to ensure that no data is lost. MIO X Series devices can handle multiple A/D conversion operations with DMA or programmed I/O.
To summarize, when you are taking an AI measuring task, the signals will be routed from channels once a time to ADC through NI-PGIA. AI FIFO allows the digitized data to be stored and then delivered to your host computer. The NI-PGIA amplifies or attenuates the AI signal depending on the input range, which you can individually program for each AI channel on your X Series device.