Appendix A: Glossary
Common Mode Voltage (VCM ) : The voltage about which a differential voltage swings. When this is measured on the SDAIBB it is calculated with all voltage readings taken in reference to GND of the SDAIBB as
(IN + + IN − ) 2 . Note that when one of the inputs is connected to GND of
the SDAIBB the common mode voltage changes as the differential voltage changes.
Differential Voltage (VDIFF ) : The difference in voltage across two points
such as the two leads on a thermocouple. When this is measured on the SDAIBB it is calculated with all voltage readings taken in reference to
GND of the SDAIBB as IN + − IN − .
Gain (G) : The amount by which the input is multiplied before it is output.
Gain = | Vout | ||
IN + | − IN − | ||
| |||
Impedance Mismatch: When the output impedance of sensor is different enough from the input impedance of the data acquisition device to cause improper sensor readings.
Negative Input Differential: When the voltage and IN- is higher than the voltage at
Negative Rail: The lowest possible voltage that can be output. For the SDAIBB there is a negative rail internal to the buffer and a negative rail on the output of the buffer.
Positive Rail: The highest possible voltage that can be output. For the SDAIBB there is a positive rail internal to the buffer and a positive rail on the output of the buffer.
SDAIBB3599 Manual |
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