Input/Output connections to IOD-24 are via a 50-pin connector on the mounting bracket. I/O connections to IOD-72 and IOD-120 are via 50-wire ribbon interface cables that extend through rectangular cut-outs in the mounting bracket and plug into headers on the card. Units required to meet EU "CE" requirements are supplied with blank mounting brackets. That permits you to use cabling method's that best fit your application.Strain relief is provided for these cables. Ready-made displacement type ribbon cables are available from ACCES as p/n CAB50F-xx. (See the Accessories section of this catalog.) Alternate wires are connected to ground to provide shielding and minimize crosstalk.
On models IOD-72 and IOD-120, you can enable/disable the I/O buffers under program control. If this is needed in a 24-bit application, a de-populated version of IOD-72 is available at reduced cost. Also, if only 96-bit operation is needed, there is a jumper on the IOD-120 to set that mode of operation. At each 24-bit port, two of the I/O lines can be used for User Interrupts; one line to enable/disable this function and one for the external interrupt signal. Interrupt levels 2-7 are selected by jumper on IOD-24. Interrupt levels 2-7, 10-12, 14, and 15 can be jumper selected on IOD-72 and IOD-120.
Card I/O bus address selection is by DIP switches on the cards. The address can be anywhere in I/O space. On power-up or reset, all ports are automatically configured as inputs. This prevents spurious outputs. Before use, of course, each PPI should be software configured by writing to its control register.
