MicroLogix 1500 Repair

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The MicroLogix 1500 series is a series of programmable logic controller systems by Allen-Bradley. Theses controllers feature a base unit that contains input and output circuits, a processor, and a power supply. With either 24 or 28 input and output embedded points, these controllers allow additional inputs and outputs to be added through the use of compact inputs and outputs. The MicroLogix 1500 programmable logic controllers are the most expandable models in the series. They come with 3 distinct configurations of embedded inputs and outputs. The controllers feature a memory of 7 KB or 14 KB. Since the base units have a power supply as well as integrated input and output, these controllers have some of the best specifications for a modular system which are not only cost-effective but also small and save space.

In addition to being able to connect to personal computers, the Allen-Bradley MicroLogix 1500 controllers can also connect to a DH-485 network through advanced interface converters (AIC) as well as an Ethernet network through an Ethernet Interface (ENI). Additionally, the controllers can be connected to a DeviceNet network by using an Allen-Bradley DeviceNet Scanner module (1769-SDN) and the Modbus SCADA network. The 1769 Compact expansion inputs and outputs also connect to the Allen-Bradley MicroLogix 1500 programmable logic controllers. Based on the system that is used, the users can use either 8 or 16 expansion I/O modules. With an operating system of (FRN) 3 or higher versions, another bank of inputs and outputs can be connected to these controllers. When the users use an expansion power supply, this increases the system’s capacity to allow for the addition of expansion input and output modules. The extra input and output banks are connected to the MicroLogix 1500 controllers through a uniquely designed cable, but they must include an end cap as well as a power supply.

Common issues with the MicroLogix 1500 include:

Plastics and mounting  

• Doors 

• Node address switches 

• Din Rail clips 

Communications

• Ethernet 

• Extension I/O port 

• RS-232 port 

• Memory module port

Lights

• Solid Fault Light 

• Flashing Fault Light

• LED indicators 

• I/O indicator lights 

I/O

• Discrete output replacement relay or TRIAC 

• Discrete input replacement 

• Analog out 

• Analog in 

• Fused input/output replacement