National Instruments sbRIO-9687 User Manual

If single-ended signals are measured, one end of the signal source and one input terminal
should be connected to ground, as in the following diagram.
Figure 8. Connecting a Single-Ended Voltage Signal to Simultaneous AI
+
–
Voltage
Source
ssAI+
ssAI–
GND
ADC
sbRIO-9687
Gain
sbRIO-9683/9684
Differential
Amplifier
Lowpass
Filter
AI+
AI–
The gain stage of each input channel can be set as x1, x2, x3, or x4. See Gain Stage on page
22 for details.
Connecting Current Output Sensors to Simultaneous Analog
Input
A large selection of current output sensors can be connected to the sbRIO-9687. For current
measurements, a current-sensing resistor converts input current into voltage. The burden
voltage of the resistor follows the same signal path as the voltage inputs.
Figure 9. Connecting a Current Output Sensor to Simultaneous AI
ADC
sbRIO-9687
Gain
sbRIO-9683/9684
ssAI+
ssAI–
Current Output
Sensor
Power
Supply
PS+
PS–
Termination
Resistor
Differential
Amplifier
Lowpass
Filter
AI+
AI–
If the sensor is powered, the sensor power supply ground should be connected to the ground
pin on the simultaneous AI connector. The common mode and differential input signal on the
burden resistor should stay within the limits listed in the Simultaneous Sampled Analog Input
section of the sbRIO-9687 Specifications.
Current-Sensing Resistor
By default, the current-sensing resistor is not populated. The current-sensing resistor pads
accommodate a resistor footprint of 2512, with a maximum dissipated power of 1 W. For
lower power applications, the sbRIO-9687 includes a 1206 footprint (0.25 W) in parallel with
the current-sensing resistor.
18 | ni.com | sbRIO-9687 User Manual

National Instruments sbRIO-9687 Specifications

General

Brand	National Instruments
Model	sbRIO-9687
Category	Controller
Language	English