National Instruments NI PCI-8254R Digital I/O

Digital I/O

The digital I/O functions on the NI 8254R are accessible through 2 TTL

inputs, 10 TTL outputs, 13 isolated inputs, and 4 isolated outputs.

You can use input signals as triggers, product selection ports, change

detectors, or to read quadrature encoders. Uses for output signals include

controlling camera reset and exposure, controlling strobe lighting,

outputting inspection results, or communicating with PLCs. You can also

define the functions of digital input and output signals.

For information about how to use LabVIEW to implement specific digital

I/O functions, refer to the examples at <LabVIEW>\examples\IMAQ\

IMAQ IO.llb. For information about how to use C or Visual Basic to

implement specific digital I/O functions, refer to the examples at

<National Instruments>\NI-IMAQ IO\Examples\.

Behind the digital I/O of the NI 8254R is an FPGA which has been

preconfigured with the functionality required for most common machine

vision tasks. If the factory configured functionality does not fulfill your

requirements, the FPGA is user configurable with the LabVIEW FPGA

Module. RIO technology, found throughout the NI platform, includes

NIPCI and PXI R Series DAQ devices, NI CVS-1450 Series Compact

Vision Systems, the NI 8254R, the NI 8255R, and NI CompactRIO. RIO

allows you to develop custom FPGA logic on compact vision systems or

with the NI 8254R device to add triggering, pulse-width modulation

signals, or custom communications protocols to your machine vision

application.

Using National Instruments RIO hardware and the LabVIEW FPGA

Module, you can define your hardware without in-depth knowledge of

hardware design tools or hardware description languages (HDL). When the

signal requirements change, the LabVIEW code can be modified and

downloaded to the FPGA to change the I/O mix or type. This flexibility

allows you to reuse the same hardware and software at no extra expense.