National Instruments NI 6013 User Manual

Also see for NI 6013: Note to Users

Contents

National Instruments NI 6013 User Manual Manual pdf 68 page image

© National Instruments Corporation 5-1 NI 6013/6014 User Manual5CalibrationThis chapter discusses the calibration procedures for the NI 6013/6014.NI-DAQ includes calibration functions for performing all of the steps inthe calibration process.Calibration refers to the process of minimizing measurement and outputvoltage errors by making small circuit adjustments. On the NI 6013/6014,these adjustments take the form of writing values to onboard calibrationDACs (CalDACs).Some form of device calibration is required for most applications. If you donot calibrate the NI 6013/6014, the signals and measurements could havevery large offset, gain, and linearity errors.Three levels of calibration are available to you and described in this chapter.The first level is the fastest, easiest, and least accurate, whereas the lastlevel is the slowest, most difficult, and most accurate.Loading Calibration ConstantsThe NI 6013/6014 is factory calibrated before shipment at approximately25 °C to the levels indicated in Appendix A, Specifications. The associatedcalibration constants—the values that were written to the CalDACs toachieve calibration in the factory—are stored in the onboard nonvolatilememory (EEPROM). Because the CalDACs have no memory capability,they do not retain calibration information when the device is unpowered.Loading calibration constants refers to the process of loading the CalDACswith the values stored in the EEPROM. NI-DAQ determines when loadingcalibration constants is necessary and does it automatically. If you are notusing NI-DAQ, you must load these values yourself.In the EEPROM, there is a user-modifiable calibration area in additionto the permanent factory calibration area. The user-modifiable calibrationarea allows you to load the CalDACs with values either from the originalfactory calibration or from a calibration that you subsequently performed.This method of calibration is not very accurate because it does not take into