Allen-Bradley Universal I/O Chassis 1771-A1B, -A2B, -A3B, and -A4B
The Allen-Bradley Universal I/O Chassis provide backplane connections for the 1771 series I/O modules, a 1771-ASB Remote I/O Adapter Module, and a combination of 1771 power supply modules. The chassis come in four sizes, the -A1B chassis has 4 slots, the -A2B chassis has 8 slots, the -A3B has 12 slots, and the -A4B has 16 slots.
Universal I/O Chassis Strapping
The Universal I/O Chassis contains a backplane switch assembly located on the left hand, lower side of the backplane as you look into the chassis. Refer the the section on the Allen-Bradley 1771-ASB Remote I/O Adapter Module for instructions on the setting of these switches. There is also a power supply configuration jumper located along the top of the backplane as you look into the chassis. This jumper should be set to the right position if an external power supply is used, and set to the left position (most common in an EPICS control system) if a power supply module such as the 1771-P4S Power Supply Module is used.
Universal I/O Chassis Module Placement
The Allen-Bradley 1771-ASB Remote I/O Adapter Module must reside in the left most slot of the I/O chassis. Other restrictions to 1771 series module placement may apply, these will be mentioned on a per-module basis.