Measurement System Types and Signal Sources

The type of input signal source (grounded or floating) and the configuration of the measurement system (differential, single-ended, psuedodifferential) determine how you connect signals to measurement devices.

The following table provides an application-independent summary of analog input connections. The resistors in the figures are not the same as those for measuring current, resistance, and strain.

Input Signal Source Type
Floating Signal Source (Not Connected to Building Ground) Grounded Signal Source
Examples: Ungrounded thermocouples, signal conditioning with isolated outputs, battery devices Example: Instruments with nonisolated outputs
Differential (DIFF)
Ground Referenced Single-Ended (RSE)

Note: AI GND is shared as a reference for all RSE channels
Nonreferenced Single-Ended (NRSE)

Note: AI SENSE is shared as a reference for all NRSE channels
Psuedodifferential
Rext is the external bias resistor that you add.