
Chapter 4 Connecting Signals
NI PCI-6110/6111 User Manual 4-16 ni.com
Figure4-7 shows DIO<0..3> configured for digital input and DIO<4..7> 
configured for digital output. Digital input applications include receiving 
TTL signals and sensing external device states, such as the switch state 
shown in Figure4-7. Digital output applications include sending TTL 
signals and driving external devices, such as the LED shown in Figure4-7.
Power ConnectionsTwo pins on the I/O connector supply +5 V from the computer power 
supply using 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 can be used to power external digital circuitry.
Power rating+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 NI PCI-6110/6111 or any 
other device. Doing so can damage the device and the computer. NI is not liable for damage 
resulting from such a connection.
Timing ConnectionsCaution Exceeding the maximum input voltage ratings, which are listed in Table4-3, can 
damage the NI PCI-6110/6111 and the computer. NI is not liable for any damage resulting 
from such signal connections.
All external control over the timing of the NI PCI-6110/6111 is routed 
through the 10 PFIs, labeled PFI0 through PFI9. These signals are 
explained 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 DAQ Timing Connections section. 
The waveform generation signals are explained in the Waveform 
Generation Timing Connections section. The general-purpose timing 
signals are explained in the General-Purpose Timing Signal Connections 
section.