The card uses six bytes of I/O Bus address; one byte for each eight bits of output. Outputs of a programmable array logic chip enable data bytes to be clocked into latches. Outputs of the latches, in turn, are connected via opto-couplers to the output P-channel FET drivers. The opto-couplers used are rated to 5 KV and on-card isolation channel-to-channel and channel-to-computer exceeds 60 Vrms. The P-Channel FET drivers are capable of 1 Ampere steady-state current (Note: Current output may be limited by the cable to as little as 0.5A). Diodes are included across the load for inductive-spike protection.
There are 48-bit, 32-bit, and 16-bit versions. The latter two models are de-populated versions of the 48-bit card.
Each bit of the IDO card is optically-isolated from the output driver which switches the supply voltage to the output pin. The negative connection is made on the return pin and each output is isolated from every other output.
When the opto-isolator is ON, the FET is activated by the Zener-diode-limited supply voltage. When the FET is ON, the full Supply voltage is available at the output pin. When the opto-isolator is deactivated, the FET opens and the output drops to the return line voltage level.
Note, because high voltages can be present, a protective cover is included and cables plugged into the headers on the card extend through this cover and exit the card through a cutout in the mounting bracket. (A strain-relief bar is also provided at that exit point.) If there is the possibility that some other card in your system will have sharp trimmed component leads that could pierce the cable(s), then you can use shielded "Zippertubing" (our part number ZTR-xx) to protect the cable and prevent possible short circuits.
On-Card: 60V rms, channel-to-channel and channel-to-computer Cable: 300 Vrms is typical ribbon-cable dielectric strength
