Inputs feature a change-of-state detection capability (denoted by a 'C' after the model number) which provides a means to automatically interrupt the host computer in real time. When one or more input bits change state, a PCI interrupt is generated to automatically wake up your application. This can greatly simplify your application program and eliminate need to continuously poll inputs.
Each input is rectified by photo-coupler diodes, therefore polarity insensitive - either positive, negative, and AC voltage inputs are acceptable. The input range is up to 60VDC or AC rms at frequencies of 40 to 10 kHz.
These cards are especially useful in applications where high common-mode external voltages are present. Isolation is required to guard electronics from transient voltage spikes and offers greater common-mode noise rejection in electronically noisy surroundings containing industrial machinery and inductive loads. These applications include factory automation, energy management, industrial ON/OFF control, security systems, manufacturing test, and process monitoring. In addition to protecting industrial applications from accidental contact with high external voltages, the isolation provided eliminates troublesome ground loops. Connections are available via 50-pin IDC type headers, ribbon cables, and a variety of screw terminal boards.
*Note on Isolation: Opto-Isolators and connectors are rated for at least 500V, but isolation voltage breakdowns will vary and is affected by factors like cabling, spacing of pins, spacing between traces on the PCB, humidity, dust and other environmental factors. This is a safety issue so a careful approach is required. For CE certification, isolation was specified at 60VDC or AC rms. The design intention was to eliminate the influence of common mode. Use proper wiring techniques to minimize voltage between channels and to ground. Tolerance of higher isolation voltage can be obtained on request by applying a conformal coating to the board.
Optically Isolated channel-to-ground or channel-to channel (*see note) Input