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Chapter 4 Signal Connections
6023E/6024E/6025E User Manual 4-30 ni.com
Power Connections
Two pins on the I/0 connector supply +5 V from the computer power
supply through a self-resetting fuse. The fuse resets automatically within a
few seconds after the overcurrent condition is removed. These pins are
referenced to DGND and you can use them to power external digital
circuitry. The power rating is +4.65 to +5.25 VDC at 1 A for the PCI and
PXI devices, and +4.65 to +5.25 VDC at 0.75A for PCMCIA cards.
Caution
Under no circumstances connect these +5 V power pins directly to analog or
digital grounds, or to any other voltage source on the device or any other device. Doing so
can damage the device and the computer. National Instruments is not liable for damages
resulting from such a connection.
Timing Connections
Caution
Exceeding the maximum input voltage ratings, which are listed in Table 4-3, can
damage the device and the computer. National Instruments is not liable for any damages
resulting from such signal connections.
All external control over the timing of your device is routed through the
10 programmable function inputs labeled PFI<0..9>. These signals are
explained in detail in the Programmable Function Input Connections
section. These PFIs are bidirectional; as outputs they are notprogrammable
and reflect the state of many DAQ, waveform generation, and
general-purpose timing signals. There are five other dedicated outputs for
the remainder of the timing signals. As inputs, the PFI signals are
programmable and can control any DAQ, waveform generation, and
general-purpose timing signals.
The DAQ signals are explained in the DAQ Timing Connections section;
the waveform generation signals in the Waveform Generation Timing
Connections section, and the general-purpose timing signals in the
General-Purpose Timing Signal Connections section.
All digital timing connections are referenced to DGND. This reference
is demonstrated in Figure 4-16, which shows how to connect an external
TRIG1 source and an external CONVERT* source to two PFI pins.