Chapter 3 Hardware OverviewNational Instruments Corporation3-3VXI-MIO Series User ManualAnalog InputThe analog input section of each VXI-MIO Series module is softwareconfigurable. You can select different analog input configurationsthrough application software designed to control the VXI-MIO Seriesmodules. The following sections describe in detail each of the analoginput categories.Input ModeThe VXI-MIO Series modules have three different input modes—nonreferenced single-ended (NRSE) input, referenced single-ended(RSE) input, and differential (DIFF) input. The single-ended inputconfigurations use up to 64 channels. The DIFF input configurationuses up to 32 channels. Input modes are programmed on a per channelbasis for multimode scanning. For example, you can configure thecircuitry to scan 48 channels—16 differentially-configured channelsand 32 single-ended channels. Table 3-1 describes the three inputconfigurations.Table 3-1. Available Input Configurations for the VXI-MIO SeriesConfiguration DescriptionDIFF A channel configured in DIFF mode uses two analoginput channel lines. One line connects to the positiveinput of the module programmable gaininstrumentation amplifier (PGIA), and the otherconnects to the negative input of the PGIA.RSE A channel configured in RSE mode uses one analoginput channel line, which connects to the positiveinput of the PGIA. The negative input of the PGIA isinternally tied to analog input ground (AIGND).NRSE A channel configured in NRSE mode uses oneanalog input channel line, which connects to thepositive input of the PGIA. The negative input of thePGIA connects to the analog input sense (AISENSE)input.
