The AB 1771-AL is a PLC 2 Local I/O Adapter Module. It interfaces with the I/O modules with PLC 2 family processors for system configuration. It receives output image table status data from the processor and transmits input status data to the processor to update output terminals status and input image table respectively. The 1771-AL is compatible with the PLC-2/20 and PLC 2/30 family processors and supports 4, 8, 12, and 16-slot I/O chassis.


The 1771-AL supports two-slot I/O-only addressing which means two adjacent I/O module slots are addressed by the processor as a single I/O group. For installation, it must be mounted on the leftmost slot of the 1771 I/O chassis. The 1771-AL supports Parallel communication and has a backplane current requirement of 700mA at 5V DC. It has dimensions of 3.5 x 6.5 x 2 in. and weighs 2.2 lbs. It has a maximum power dissipation of 5W and thermal dissipation of 17.06 BTU/hr.


The 1771-AL module has Active and Rack Fault diagnostic indicators at the front of the module. It has a chassis backplane connector at the back edge and two connectors at the front. The top front connector connects to the processor or an I/O chassis near the processor and bottom front connector connects to the I/O chassis far from the processor or to an I/O termination plug. The 1771-AL is intended for use in an industrial environment with a 0° – 60°C (32° – 140° F) operating temperature and a 5 – 95 % (without condensation) relative humidity.