The 1771-LC3 controller is a loop controller that helps in continuous process automation in industrial settings. The 1771-LC3 loop controller is an Allen-Bradley loop controller for Allen-Bradley PLC 5 devices. It runs with an input voltage rating of 120 Volts AC. It is a microprocessor-based device which is used in different application processes. An operator interface terminal is present on the front side of the controller. There are 8 user-configurable keys on the controller, including navigation, selection, and acknowledge keys. It also comes with a resistance temperature detector input option. Three LED indicators are present on the front panel to show the operating status of the module. The 1771-LC3 controller has a current rating of 30 VA. The back panel of the loop controller comes with three terminals: the L1, L2, and GND terminals. Mounting can be done by using bolt screws. The loop controller is able to display 50-segment bar graphs along with value data in an alpha-numeric format.

The Allen-Bradley 1771-LC3 controller can be operated at up to a maximum temperature of 55 degrees Celsius. The loop controller receives generic and controller specific commands from the programmable controller and it interprets and processes them. It can help to monitor and change the setpoint and reset alarms. The 1771-LC3 controllers can help to examine the PID parameters, alarm points, and output limits. The loop controller uses the Set control command which is used to supply basic control and status command changes to one or more controllers. The loop controller can interpret two types of data: Binary and BCD data. The 1771-LC3 loop controller controls shows diagnostics and ICI error codes when an error occurs in the system.