National Instruments NI CVS-1450 Series User Manual

Table 4-3 lists the product selection ports.

General-purpose inputs and outputs are available as both TTL and isolated 
connections. At any time, the software running on the CVS-1450 device 
can read the inputs and drive the outputs high or low.

The primary difference between general-purpose inputs and trigger inputs 
is that you cannot use general-purpose inputs to initiate a timed pulse 
generator. In an application, use the general-purpose inputs to get the status 
of the inputs at a given point and not to synchronize the CVS-1450 device 
with an external event. 

An example of how to use general-purpose inputs is reading the status of 
a general-purpose input as the first step in your inspection sequence and 
recording that value as part of your inspection.

The primary difference between general-purpose outputs and timed pulse 
outputs is that the timing of general-purpose outputs is controlled by 
software rather than hardware. As a result, timing of general-purpose 
outputs changes as the inspection algorithm changes, which makes 
general-purpose outputs less appropriate than timed outputs for camera 
control, strobe light control, and other applications that require precise 
timing.

Table 4-3.  Product Selection Port

Data(5), rising edge latch

 ISO Input 5

Data(4)

 ISO Input 4

Data(3)

 ISO Input 3

Data(2)

 ISO Input 2

Data(1)

 ISO Input 1

Data(0)

 ISO Input 0