The Allen-Bradley 5250-LP1 is the logic processor for the PLC-5/250 programmable controller. It is installed in the 8-slot controller chassis and performs the following functions: execution of logic control and provision of memory for data tables. The PLC-5/250 controller is the most powerful member of the PLC-5 family. The 5250-LP1 offers multiple benefits including enhanced memory and I/O handling capacity, multi-processor capability, enhanced parallel processing, concurrent execution of multiple tasks, and support for multiple communication protocols (Ethernet, DH /DH+, DECnet). An 8-slot Pyramid Integrator chassis houses the various modules of the 5/250 controller including a power supply, resource manager, DH/DH+ interface, logic processor, and remote/local I/O scanners. The 5250-LP1 is the logic processor for the 5/250 system with 256K words of memory (5250-LP2 with 512K words of memory, 5250-LP3 with 1024k words of memory and 5250-LP4 with 2048K words of memory are also available). A maximum of four logic processor modules can be installed in one 5/250 system. The 5250-LP1 can support up to 4096 inputs and outputs.

The 5250-LP1 is tasked with the execution of SFCs (sequential function charts) and ladder logic. With multiple LPs (logic processors) per chassis, the applications can be segmented and specific tasks can be assigned to different LPs. The LPs execute compiled code for programs and this code executes faster compared to interpreted code for programs. LPs allow up to 8 time-interval-based interrupt routines and a maximum of 4 event-based interrupt routines. Additionally, the 5250-LP1 has background programs – 4 can be active concurrently out of a total of 32 – and they can execute in the background while the main program is running. These background programs can be used for fault recording or data manipulations. The 5250-LP1 weighs 1.74 kg. It draws 1.82 A at +5V DC and 0.02 A at +12V DC.