Skip to content

Setting up a MicroLogix PLC


  • Allen-Bradley Edition or Ultimate Edition
  • Compatible MicroLogix 1100/1400 PLC with Ethernet connection
  • RSLogix 500

This tutorial gives you step-by-step instructions on how to use a MicroLogix 1100 PLC to control Factory I/O. These same steps apply to the MicroLogix 1400 models.

Setting up communication between PC and PLC

  1. Connect the PLC to the network.

  2. Assign an IP address to the PLC.

    To complete this step you should refer to the MicroLogix 1100 Programmable Controllers User Manual 1763-UM001 / MicroLogix 1400 Programmable Controllers User Manual 1766-UM001, which describes methods to assign an IP address to the controller. By default, the controller is BOOTP enabled and will be assigned an IP address by a BOOTP server on the network.

  3. Start RSLinx and open the driver configuration dialog by selecting Communications > Configure Drivers from the menu.

    open driver configuration

  4. Add an EtherNet/IP driver.

    add ethernet/ip driver

  5. You should now be able to find the controller under the newly added driver.

    device found

Connecting Factory I/O to the PLC

  1. In Factory I/O click on FILE > Driver Configuration to open the Driver Window.

    open driver window

  2. Select Allen-Bradley MicroLogix from the driver drop-down list.

    select micrologix driver

  3. Open the driver Configuration Panel by clicking on CONFIGURATION.

  4. Make sure 1100 Ethernet is selected in the Model drop-down list and insert the controller's IP address into the Host field. If you are using a 1400 model select 1400 from the Model list instead.

    driver config

    On this panel you can also define how many I/O Points to use, as well as what part of the controller's memory (tags) they reference.

    Each I/O point (e.g. B3:0/0) must be associated with an element of the PLC data file. Note that you can use any data file for Bool, Float and Integer but the following rules apply:

    • For Bool Inputs/Outputs, Count represents the number of bits. This means that if you would need 32 bits for Bool Inputs you would have to define, at least, 2 elements (Word) in the corresponding data file.
    • For Float and Integer points, Count represents the number of elements (Word).

    See MicroLogix Configuration.

    i/o points to elements association

  5. Press Esc to return to the Driver Window. Now, click on CONNECT to connect to the PLC. A successful connection is indicated by a green icon next to the selected driver, as well as next to the driver's name displayed on the status bar.

    tag error

    When connected to a PLC, non-existent tags or tags with an error are grayed out. Hover the mouse cursor over a grayed-out point to get relevant information about the error.

Creating Elements in RSLogix 500

  1. Create a new project in RSLogix 500.

    Once a new project is created, one BINARY, OUTPUT, and FLOAT elements are already defined. You must have, at least, as many elements as the ones defined in Factory I/O. Note that you are missing 7 FLOAT elements, 3 for inputs (F8:1 ... F8:3) and 4 for outputs (F8:4 and F8:7).

  2. Right-click on F8 - FLOAT data file and select Properties....

    float data file

  3. Change the number of elements to 8 and click on Apply.

    float data file properties

  4. Select Comms > Download... to send the new program to the PLC.

    download to the plc

Back to top