Allen-Bradley 1756-L61 ControlLogix Processor Module

The Allen-Bradley 1756-L61 ControlLogix Processor Module is a 5561-series controller that plugs into a 1756 ControlLogix backplane to execute industrial automation programs within a scalable ControlLogix chassis. It provides 2 MB of fixed memory for data and logic and 478 KB of dedicated I/O memory, with optional nonvolatile backup via a CompactFlash card. This processor includes an RS-232 serial port for device communications and a typical program scan time of about 0.08 ms, enabling fast, deterministic control in demanding applications. It supports up to 128,000 I/O points in a single configuration and draws 1.2 A from the 5 V backplane and about 14 mA from the 24 V supply, with a tested weight of ~0.71 lb (0.32 kg). For memory backup, compatible batteries such as 1756-BA1 or 1756-BATM are specified. The unit is designed for harsh industrial environments, with an operating humidity range of 5 to 95 percent and vibration tolerance from 10 to 500 Hz. The 1756-L61 sits alongside other ControlLogix 5561 processors such as the 1756-L62 and 1756-L63, which offer larger fixed memory configurations for more extensive control logic and data, underscoring its role as a reliable workhorse in large-scale automation projects.