The Allen-Bradley 1769-L31 is a Programmable Automation Controller (PAC) that is part of the 1769 CompactLogix controller family. This controller is ideal for use in small to medium scale applications. This controller is provided with dual RS232 communication interfaces, specifically channel 0 that supports DF1, DH-485 and ASCII protocols and channel 1 that supports DF1 and DH-485 protocols.

Channel 0 is a fully isolated port while Channel 1 is a non-isolated port, both supporting up to 38.4 kbps transmission speed. It also comes with a user memory of 512Kbytes and non-volatile memory option through the 1784-CF64 or 1784-CF128 CompactFlash card.

This controller supports up to Sixteen (16) local I/O modules and may be expanded up to Three (3) banks of Input and Output modules for system expansion. This controller must be installed not more than Four (4) modules away from the power supply, designated by its power supply distance rating.
It is also equipped with commissioning such as I/O forcing for rapid engineering of the controller.

The 1769-L31 comes with easily identifiable LED indicators such as RUN, FORCE, BAT, OK, I/O, DHC0, Channel 0 and Channel 1 LED indicators. Each of these LED operate independently to depict the current controller status.

This controller comes with a 1747-BA battery that is used to maintain contents of user memory where the program is downloaded. This battery is a replaceable unit and provided with a Battery (BAT) status LED. Only one controller can be used in a CompactLogix system.

The 1769-L31 controller has 512 KB of available user memory. It has Two (2) RS-232 serial ports for communication with one for the system or user protocols and one for system protocol only. It can support a maximum of 4 tasks, 16 local I/O modules, and 3 I/O banks. It has a current requirement of 330mA at 5V DC and 40mA at 24V DC. It has a dimension of 8 x 8 x 5 in. and weighs 2 lbs. For installation, it uses the DIN-rail or panel mounting method with an open enclosure. It must always be the leftmost module and be within four modules of the system’s power supply. For wiring, the 1756-CP3 or the 1747-CP3 serial cable with a 2mm^2 (14- 22 AWG) category standard is used. The 1784-CF128 Industrial CompactFlash card can also be installed as a nonvolatile memory. The 1769-BA is the only battery module compatible with this controller.
The 1769-L31 controller has LED status indicators for various commands such as Run, Force, Battery, I/O, and Ok. It is intended for use in overvoltage category II industrial standards with 0 - 60 °C operating temperature and 30g operating shock.