Allen-Bradley 1771-DB Programmable Logic Controller Module

Allen-Bradley 1771-DB Basic Module is a PLC-5 era BASIC programming module that plugs into a 1771 I/O rack, occupying a single slot. It provides a built-in BASIC interpreter and runs user-written programs to perform arithmetic, data handling, and simple reporting, using block-transfer communication with the PLC-5 processor via the 1771 backplane. This module allows on-rack data manipulation and task automation separate from ladder logic, letting engineers implement calculations, data formatting, and lightweight data processing within a PLC-5 installation that uses the 1771 I/O system. Typical use cases include pre-processing I/O data for reports, performing unit conversions, or deriving values from sensor data before or alongside ladder logic, with results exchanged back to the processor through the 1771 block-transfer mechanism. The 1771-DB is designed specifically for PLC-5 systems and provides BASIC language capabilities, including math functions and report generation, for processors that support the 1771 I/O backplane block-transfer interface.