National Instruments SCB-68A - Page 7

Contents
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Using the Temperature Sensor..........................................................................................2-16
Taking Thermocouple Measurements ...................................................................... 2-16
Temperature Sensor Output and Accuracy...............................................................2-17
Thermocouple Sources of Error................................................................................ 2-17
Open Thermocouple Detection................................................................................. 2-18
Thermocouple Input Filtering...................................................................................2-19
Installing Bias Resistors.................................................................................................... 2-20
Lowpass Filtering ............................................................................................................. 2-21
One-Pole Lowpass RC Filter .................................................................................... 2-24
Selecting Components for Lowpass Filtering........................................................... 2-24
Adding Components for Lowpass Filters on Analog Input Signals .........................2-25
Analog Input Lowpass Filtering Applications.......................................................... 2-26
Highpass Filtering............................................................................................................. 2-27
One-Pole Highpass RC Filter ...................................................................................2-29
Selecting Components for Highpass Filtering..........................................................2-29
Adding Components for Highpass Filtering on Analog Input Signals..................... 2-30
Analog Input Highpass Filtering Applications .........................................................2-31
Current Input Measurement ..............................................................................................2-32
Selecting a Resistor for Current Input Measurement................................................2-33
Adding Components for Current Input Measurement on Analog Input Signals ......2-33
Attenuating Voltage ..........................................................................................................2-35
Selecting Components for Attenuating Voltage .......................................................2-36
Accuracy Considerations for Attenuating Voltage ...................................................2-36
Adding Components for Attenuating Voltage on Analog Input Signals .................. 2-37
Analog Input Voltage Dividers.................................................................................2-38
Chapter 3
Analog Output Waveforms
Analog Output Channel Pad Configuration......................................................................3-1
Lowpass Filtering ............................................................................................................. 3-2
One-Pole Lowpass RC Filter .................................................................................... 3-5
Selecting Components for Lowpass Filtering...........................................................3-6
Adding Components for Lowpass Smoothing Filters on Analog Output Signals....3-6
Analog Output Lowpass Filtering Applications ....................................................... 3-7
Attenuating Voltage ..........................................................................................................3-8
Selecting Components for Attenuating Voltage .......................................................3-9
Accuracy Considerations for Attenuating Voltage ...................................................3-9
Adding Components for Attenuating Voltage on Analog Output Signals ............... 3-9
Analog Output Voltage Dividers .............................................................................. 3-10