PCIbus I/O boards use safe current-source circuits

Edited by the Electronicstalk editorial team Nov 23, 2004

The PIO-32/32RL(PCI)H and PIO-16/16RL(PCI)H are optoisolated digital I/O boards for PCIbus systems.

Contec has developed the PIO-32/32RL(PCI)H and PIO-16/16RL(PCI)H optoisolated digital I/O boards for PCIbus systems.

These new optoisolated digital I/O boards for the PCIbus feature reverse-common (current source) I/O circuits and are suitable for use as components in PC-based instrument control systems.

The two new models are digital signal I/O interface boards for the PCIbus and can perform digital I/O of signals in the range 12 to 24V DC.

The output circuits use current source (NP) transistor outputs with photocoupler isolation.

The input circuits also use photocoupler isolation and can connect to current source outputs.

The PIO-32/32RL(PCI)H has 32 input and 32 output channels.

The PIO-16/16RL(PCI)H has 16 input and 16 output channels.

Although control systems typically use current-sink circuits for control signals because they are easier to use, current-source circuits (as used in these boards) are safer because inputs go to the "off state" if disconnected or shorted to common, and the output load goes to the "off state" if the output is disconnected or shorted.

As a result, use of current source circuits is becoming more common in systems where safety is an important consideration.

Also, as these boards are the PCIbus version of Contec's ISAbus boards with the same I/O specifications, they can be used in PCIbus systems that replace old ISA board based systems.

The two boards are sold complete with driver software for both Windows and Linux, and application software can be developed using Visual Basic or Visual C++ on Windows, and gcc or Kylix on Linux.