Allen-Bradley 1771-AL

The 1771- adapter module can be used with any 1771 I/O chassis. Communication between the discrete analog module and the processor is bidirectional; the processor block-transfers output data through the output image table to the module and block-transfers input data from the module through the input image table. The module also requires an area in the data table to store the read block transfer data and write block transfer data. I/O image table use is an important factor in module placement and addressing selection.