The Allen-Bradley 1772-LN1 PLC-2 Mini Processor Module is a control processing and memory unit that is made for the Allen-Bradley Mini-PLC-2 controllers.  It has 512 words of memory capacity and 128 maximum I/O and it weighs 2.5 pounds. The module is located in the leftmost slot in the 1771 I/O chassis. It has 3 diagnostic indicators which are the PROCESSOR, MEMORY, and RUN indicators. The mode select switch has the RUN, TEST, and PROG operating modes. The operating temperature of the module is 0 to 60 degrees Celsius and the relative humidity range is 5% to 95% without condensation. The memory capacity of the 1772-LN1 PLC-2 Mini Processor Module can be increased to 1024 words by using an optional memory expansion module such as the Allen-Bradley 1772-MH memory expansion module.

The 1772-LN1 PLC-2 Mini Processor Module has a Read/Write CMOS memory that stores user program instructions and I/O device status updates. It has a programmable memory and the user program can be readily changed according to the application. It can perform additional functions such as timing/counting operations, arithmetic operations, and data comparison. This processor monitors input conditions and controls output devices according to the user’s program instructions. The 3 processor diagnostic indicators that are located on the front panel of the processor module include a red indicator that illuminates if the processor is unable to scan the user program and the data table and the red memory indicator that illuminates if the processor detects the loss of the user program. The Mini-PLC-2 controller with the 1772-LN1 module can be used in a wide variety of industrial applications such as pollution control monitoring, measurement, and gaging applications.