Connecting Timing Signals
 | Caution Exceeding the maximum input voltage ratings, which are listed in the I/O Terminal Summary table in the specifications document for each S Series device, can damage your device and the computer. NI is not liable for any damage resulting from such signal connections. |
The 10 programmable function interface (PFI) pins labeled PFI <0..9> route all external control over the timing of the S Series device. These PFIs are bidirectional; as outputs they are not programmable and reflect the state of many analog input, waveform generation, and counter 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 all analog input, waveform generation, counter timing signals.
All digital timing connections are referenced to D GND. The following figure shows this reference, and how to connect an external AI START TRIG source and an external AI SAMP CLK source to two PFI pins.
