© National Instruments Corporation v NI USB-621x User ManualContentsAbout This ManualConventions ...................................................................................................................xiiiRelated Documentation..................................................................................................xivNI-DAQmx for Windows................................................................................xivLabVIEW ........................................................................................................xivLabWindows™/CVI™....................................................................................xvMeasurement Studio........................................................................................xvANSI C without NI Application Software ......................................................xv.NET Languages without NI Application Software ........................................xviDevice Documentation and Specifications......................................................xviTraining Courses .............................................................................................xviTechnical Support on the Web ........................................................................xviChapter 1Getting StartedInstalling NI-DAQmx ....................................................................................................1-2Installing Other Software...............................................................................................1-2Installing the Hardware..................................................................................................1-3Device Pinouts ...............................................................................................................1-3Device Specifications ....................................................................................................1-3Device Accessories ........................................................................................................1-3Chapter 2DAQ System OverviewDAQ Hardware ..............................................................................................................2-1DAQ-STC2......................................................................................................2-2Calibration Circuitry........................................................................................2-2Signal Conditioning .......................................................................................................2-3Sensors and Transducers .................................................................................2-3Programming Devices in Software ................................................................................2-4Chapter 3Connector InformationI/O Connector Signal Descriptions ................................................................................3-1+5 V Power ....................................................................................................................3-2+5 V Power as an Output ................................................................................3-2+5 V Power as an Input ...................................................................................3-3