Digital I/O Signal Connections; Figure 3-2. Daqcard-500 Analog Input Connections - National Instruments Corporation DAQCard-500 User Manual

Chapter 3
Floating Measurement System
Example
• Battery powered laptop
Grounded Measurement System
Example
• Desktop computer connected
to building ground

Digital I/O Signal Connections

Pins 12 through 19 of the I/O connector are digital I/O signal pins. Pins 12 through 15 are digital
input pins. Pins 16 through 19 are digital output pins. Pin 27 is the digital ground pin.
The following specifications and ratings apply to the digital I/O lines.
• Absolute maximum voltage input rating
• Absolute minimum voltage input rating
© National Instruments Corporation
Floating Signal Source
Examples
• Isolated outputs
• Battery devices
• Thermocouples
Signal
(2)
(3)
+
-
(4)
(5)
(9)
(1)
Signal
(2)
(3)
+
-
(4)
(5)
(9)
(1)

Figure 3-2. DAQCard-500 Analog Input Connections

DAQCard-500
Mux Signal
+
+
-
-
AIGND
DAQCard-500
Mux Signal
+
+
-
-
AIGND
+5.5 V with respect to DGND
-0.5 V with respect to DGND
3-5
Signal Connections
Grounded Signal Source
Example
• Nonisolated instruments
DAQCard-500
Mux
(2)
(3)
+
(4)
-
(5)
(9)
(1)
AIGND
NOT RECOMMENDED
DAQCard-500
Mux
(2)
(3)
+
(4)
-
(5)
(9)
(1)
AIGND
Ground
Current
- Building (Earth) Ground
DAQCard-500 User Manual