Product Description:

Pacific Scientific manufactures the CA950-IO digital input/output option board as part of the OC950 Option Cards series. Designed for rack-based motion or process controllers, the card extends discrete control capacity by interfacing external limit switches, photo eyes, relays, and solenoids with the host CPU. By translating 24 V-style field signals into rack logic levels, it provides a compact method for integrating machine status indications and command outputs in industrial automation cells.

The CA950-IO supports 21 channels, each passing through a 100 µs digital filter that suppresses contact bounce and fast transients before the controller samples the state. Field wiring lands on the front-panel 50-contact receptacle, while rack communication returns through a 25-contact male D-sub to maintain a clear separation between plant cabling and internal logic. Input stages are biased by a 10 kΩ pull-up to +12 VDC so inactive lines remain at a defined high level, and a transition to logic low is recognized once the voltage drops below 1.0 V minimum. The card occupies only one slot, and up to 16 modules can share the common 5 V backplane when the user rail is held at 5 V ±5%. A 50-pin Opto 22 Gen 4 header links the board to the OC950 rack for power and strobed data exchange.

On the output side, switching devices are open-drain DMOS transistors that can sink 100 mA per channel without exceeding the specified thermal limits. These drivers tolerate logic rails up to 40 V, giving ample margin for typical 24 V field loads, and they treat the line as high only after the incoming signal rises above the specified 3.5 V maximum threshold to prevent false retriggers. The user supply rail may source as much as 200 mA to external sensors through the card’s auxiliary terminals, so moderate current loads can be powered directly from the rack.