1772-LX

The Allen-Bradley/Rockwell Automation 1772-LX processor is a Mini-PLC-2/16 processor that is the main part of the Allen-Bradley PLC 2 industrial automation PLC system. The Allen-Bradley 1772-LX has 4000 words of backup EEPROM, 4000 words of general memory, and 3968 words data table expansion. The processor’s set of EAF instructions that are available include the add, subtract, multiply, divide, sqr, BCD to binary, binary to BCD, FIFO load, FIFO unload, log10, sinX, cosX, and 10x instructions. The 1772-LX PLC processor itself has 2 distinctive essential parts, the CPU and internal memory. The CPU or Central Processor Unit is a decision-maker device that uses inputs from I/O modular units and the program written by users in the ladder programming technique. The memory holds all the relevant information in the data table for the CPU to use, stores programs, sets of instructions, subprograms, and functions, and stores messages.

The 1772-LX processor has a PROC light indicator in the top part that lights up green when the 1772-LX processor is in operation and red when the PLC-2/16 processor is in a fault condition, and it does not light up when the PLC processor is in program mode. A battery can be inserted in the module on the front side to protect the stored memory. The BATT light turns red when the battery should be replaced. There is a key switch selector on the front cover of the 1772-LX processor that has 4 possible positions: the PROG (program), R/P (run/program), RUN, and the MEM STORE position which transfers programs to backup the EEPROM. On the lower part of the 1772-LX PLC processor, there is a 15-pin INTFC connector and interface port. This port is used to load “0” and “1” logic-based programs that users write on the 1784-T50 (or 1770-T3) program processing device. It is also used to pair the 1772-LX processor with numerous industrial automation parts like the Allen-Bradley 1770-T11, 1770-RG, 1772-KG, and the 1771-KA parts.