Chapter 4
Signal Connections
©
National Instruments Corporation
4-15
Power Connections
Two pins on the I/O connector 5 V from the computer power
supply via a self-resetting fuse. The fuse will reset automatically within
a few seconds after the overcurrent condition is removed. These pins are
referenced to DGND and can be used to power external digital circuitry.
• Power 4.65 to +5.25 VDC at 1 A
Caution: Under no circumstances should you connect these +5 V power pins directly
to analog or digital ground or to any other voltage source on the 611X E
board or any other device. Doing so can damage the 611X E board 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 4-2, can damage the 611X E board and the computer. National
Instruments is
NOT
liable for any damages resulting from such signal
connections.
All external control over the timing of the 611X E board is routed
through the 10 programmable function inputs labeled PFI0 through
PFI9. These signals are explained in detail in the next section,
Programmable Function Input Connections.
These PFIs are
bidirectional; as outputs they are not programmable 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
section
later in this chapter. The waveform generation signals are explained in
the
Waveform Generation Timing Connections
chapter. The general-purpose timing signals are explained in the
General-Purpose Timing Signal Connections
section later in this
chapter.
!
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PCI_E.book Page 15 Thursday, June 25, 1998 12:55 PM
