Description: This Allen-Bradley MicroLogix 1500 Base Module is powered via 24 Volts DC and has 512 Max IO Expansion. It has 28 channels with 16 inputs and 12 outputs. It is Din Rail mountable and has one RS-232 communication port.

1 year Warranty Included



The Allen-Bradley 1764-28BXB base is a part of the Allen-Bradley Bulletin 1764 MicroLogix 1500 base unit series that features embedded I/O and accommodates a processor. It is an essential component in the system assembly of Allen-Bradley MicroLogix 1500 programmable controllers. In addition to the embedded inputs and outputs, the 1764-28BXB base unit houses the power supply and the channel 0 communications port. It also serves as an interface to the expansion I/O as required by a system application. The 1764-28BXB 24 Volt DC Base Unit has 30 Watts of power consumption, 16 Watts of maximum load power, and 400 mA of maximum load current. It comes with 6 relay outputs and 2 isolated relays per unit. It has 8 standard and 8 fast 24 Volts DC inputs. The 1764-28BXB’s high-speed 20 kHz I/O is composed of 8 inputs and 2 outputs. Plus, it has 4 standard FET outputs and 2 fast FET outputs. The FET transistor is only available on this base unit.

The Allen-Bradley 1764-28BXB Base is a required piece of hardware that allows an assembled Allen-Bradley MicroLogix 1500 controller system to supports the maximum number of I/O expansions. It has a width of 168 millimeters (6.62 inches) and a depth of 87 millimeters (3.43 inches). Its height is 138 millimeters (5.43 inches) when the DIN rail latch is open, and its height is 118 millimeters (4.65 inches) when it is closed. The 1764-28BXB is designed to be mounted horizontally on the compact expansion I/O. This unit is compatible with the Allen-Bradley 1764-LRP and 1764-LSP processors.  The Allen-Bradley MicroLogix 1500 fault codes can be found in the product manual.

Technical Specifications


Rockwell Automation



Part Number/Catalog No.



MicroLogix 1500


Base Controller

I/O Count

16 inputs/12 outputs

Max Expanded I/O Count


Input Voltage

24 Volts DC

Output Source

Relay Port and DC FET


5.43 x 6.62 x 3.43 inches

Input Circuit Type

24 Volt DC Sink/Source

Output Circuit Type

6 Relay, 6 FET Transistor

Line Power

20.4-30.0 Volts DC

Power Supply Usage

30 Watts

Compatible Processors

1764-LSP and 1764-LRP

Maximum Load Current

400 mA

Product Lifecycle Status*