Chapter4 SignalConnections
6023E/6024E/6025EUser Manual 4-30 ni.com
Power Connections
Two pins on the I/0 connector supply +5 V from the computer power
supplythrough 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 Underno circumstances connect these +5 V power pins directly to analog or
digitalgrounds, or to any other voltage source on the device or any other device. Doing so
can damage the devicean d the computer.National Instruments is notliable for damages
resulting from such a connection.
Timing Connections
Caution Exceedingthe maximum input voltage ratings, which are listed in Table 4-3, can
damage the deviceand the computer. National Instruments is not liable for any damages
resulting from such signal connections.
All externalcontrol over the timing of your device is routed through the
10 programmable function inputs labeled PFI<0..9>. These signals are
explainedin detail in the Programm able Function Input Connections
section.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 fiveother 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.
TheDAQ signals are explained in the DAQ Timing Connections section;
the waveformgeneration signals in the Waveform Generation Timing
Connections section, and the general-purpose timing signals in the
General-Purpose Timing Signal Connections section.
Alld igital timing connections are referencedto DGN D. This reference
is demonstrated in Figure 4-16, which showshow to connect an external
TRIG1 source and an external CONVERT*source to two PFI pins.