Isolated Digital Input/Output Cards
The PCI-IIRO-16 is a low-cost, half-size card that provides isolated input and output for PCI Bus computers. It has sixteen optically-isolated digital inputs for AC or DC control signals and sixteen electro-mechanical relay outputs. The PCI-IIRO-16 occupies eight consecutive eight-bit registers in I/O space.
The isolated inputs can be driven by either AC or DC and are not polarity sensitive. Input signals are rectified by a diode bridge and applied to the inputs of opto-isolators. A 470 ohm resistor in series provides current limiting. Standard 12/24 AC control transmitter outputs can be accepted as well as DC voltages. The input voltage range is 5V to 24V (rms). To extend the input voltage range, you may connect external resistors in series.
Each input circuit contains a switchable slow/fast filter that has a 5 millisecond (PCI-IIRO-16) time constant. (Without filtering, the response is 20 microseconds.) The filter must be selected for AC inputs in order to eliminate response to zero crossings. The filter is also valuable for use with slow DC input signals in a noisy environment. The filter may be switched out for DC inputs in order to obtain faster response. The filters are globally controlled by software.
Interrupts are enabled/disabled by software. When the change-of-state detection circuit is enabled, the card asserts an interrupt whenever one or more of the interrupts changes state. Once an interrupt has been generated and serviced, it must be cleared by system software. This feature greatly frees up system resources by eliminating the need for constant polling to see when an input has changed state.
The electro-mechanical relay outputs of the PCI-IIRO-16 are comprised two groups of five form C SPDT outputs and three Form A SPST (normally-open) outputs.The relays are all de-energized at power-on. Data to the relays is latched.
The PCI-IIRO-16 I/O is accessed via a 78 pin DBF connector on the mounting bracket of the card. A molded breakout cable (model CAB78-37/2) is optionally available that divides the 78 pins into two DB37F connectors. Also available is a kit (model STB-37/2 Kit) which includes the cable and two STB-37 Screw Terminal Cards that mount into an included one-foot length of Snap-Trak.
See the ORDERING INFO tab for options and accessories.