The 1775-L4 is a programmable controller processor module manufactured by Allen Bradley under the PLC-3/10 series of controllers. The 1775-L4 has been engineered as a single slot processor module to offer programmable execution and management of memory functions. The 1775-L4 comes with over 70 programming instructions and a completely flexible data table. The 1775-L4 is a powerful processor-expandable module offering efficient programming capabilities.  1775-L4 has a high-speed program scan and hence processes only the parts of the control program needed. It comes with various program control instructions which include JMP, JSR and MCR program control instructions. The module also supports timed interrupt routine and has programmable fault response abilities. These features are important since they allow reactions to any major fault and hence possibly preventing the processor from faulting.

The 1775-L4 supports multiple contexts, which is a feature that is not included on any other programmable controller. This allows the user of the 1775-L4 to record and handle numbers for production counts and also inventory. The 1775-L4 stores multiple programs in one processor program and allows for procedures access based on specific date and time. The onboard diagnostics and diagnostic indicators include a green LED and Red LED indicators for easy troubleshooting. The green LED shows “pass” while the Red LED shows a failed state. Therefore, through the onboard indicators, you can continuously check modules so as to determine if the processor is functioning as it should. When installing the 1775-L4, ensure that the power supply is first shut off, before removing or insert the processor. Otherwise, this will lead to a serious damage of the 1775-L4. The environmental conditions include operating temperature of 0 to 60 degrees Celsius and the storage temperature is -40 to 85 degrees Celsius. The relative humidity for the 1775-L4 is 5 to 95% non condensing.