Table 1. PCIe-7846 Signal Descriptions (Continued)
Signal
Description
DIO
Digital input/output signal connection
DGND
Ground reference for the digital signal
EXTCLKIN
External clock input source that can be used for source synchronous
acquisitions. The provided clock source must be stable and glitch-free.
GND
Ground connection
Supply (+5 V
out
) 5 V power output connection for external devices
NC
No connection
The PCIe-7846 is protected from overvoltage and overcurrent conditions.
Note
Refer to the device specifications, available at
ni.com/manuals
for more
information.
Analog Input
The PCIe-7846 provides connections for eight AI channels. Each channel has an AI+ pin, AI-
pin, and AIGND pin to which you can connect both single-ended or differential voltage
signals. Use the AISENSE pin to connect non-referenced single-ended signals.
Connecting Single-Ended Voltage Signals
To connect referenced single-ended voltage signals to the PCIe-7846, you must connect the
voltage ground signal to AI GND in order to keep the common-mode voltage in the specified
range.
Figure 2. Connecting Referenced Single-Ended Signals to the PCIe-7846
PGIA
ADC
AI+
NI PCIe-7846
Connection
Accessory
AISENSE
AIGND
V
1
+
–
Overvoltage
Protection
AI–
Overvoltage
Protection
Overvoltage
Protection
NI PCIe-7846 User Manual
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© National Instruments
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