How to setup RSLinx comms and connect to a MicroLogix 1500

So you need to know how to setup RSLinx Classic to communicate to an Allen-Bradley MicroLogix 1500 in order to download or go online with RSLogix?

Well you're in luck as in today's article I'll walk you step by step through how to setup RSLinx communications, as well as how to download or go online from RSLogix:

Notes and prerequisites: Before you begin, insure you have the correct software and programming cable. If your PC does not have a built-in serial port you'll also need a USB to Serial converter. For images of the MicroLogix 1500 communications ports see this article.

Step 1) Start by checking Windows Device Manager to determine your PC's serial port COM number:


Step 2) Next launch RSLinx Classic, and then under the Communications menu select Configure Drivers:


Step 3) Then from the Available Driver Types drop down list select RS-232 DF1 Devices and then click on Add New:


Step 4) Accept the default name by clicking on OK:


Step 5) Now select the COM port you looked up earlier, and check to be sure you have plugged your MicroLogix 1500 into it:


Step 6) Now click on Auto-Configure. If your cables and Micro are in working condition, and your Micro is set to the default DF1 protocol, then you should see the message, “Auto Configuration Successful”:


Step 7) Now click on OK to close the RS-232 DF1 Devices driver window:


Step 8) And click on Close to close the Configure Drivers window:


Step 9) Next, double click on your new driver in the RSWho window as shown below:


Step 10) After a few seconds you should see your Micro appear under the AB_DF1-1 driver:


Step 11) Now open either RSLogix Micro or RSLogix 500, and then open your program file:


Step 12) Next, from the Comms menu select System Comms:


Step 13) In the popup Communications window expand your AB_DF1-1 driver and select your Micro:


Step 14) Then to download your program select the Download button. Alternatively, you could go online by selecting the Online button:


Step 15) At this point if you made any changes to your program you may be prompted to save it:


Step 16) Next, confirm you would like to download your program into the Micro you selected:

NOTE: The MicroLogix PLC can only hold one program at a time, and downloading to it will erase the Micro's current program. If you do not have a copy of the current program loaded in your Micro, you should first perform an upload and save.


Step 17) At this point if the Controller is different you will be asked to confirm the change

Step 18) And if the Micro was in Run Mode you'll be asked if you would like to put it into Program Mode so the download can take place.

Step 19) Next, if the communications settings in your Micro are different than the settings in the program you are downloading, you will receive a notice as to whether or not you want to change the Micro to match the program you are downloading:

NOTE: If you change the settings of the port you are downloading to, after the download you likely will lose communications with the Micro. To regain comms you'll have to edit your driver in RSLinx to match the new settings.

Step 20) At the end of the download process, if you still have communications with the MicroLogix controller you will be given the option of putting the controller back into the Run Mode if it was in the Run Mode prior to downloading, and you'll also receive the option of going online:


NOTE: You can watch a video demonstration of this procedure below:

I hope today's article about how to setup RSLinx Classic to communicate to a MicroLogix 1500 helpful.

If you have any questions, comments, or suggestions, please feel free to post the by clicking on the “Click here to post a comment or question” link below.


Shawn Tierney
Automation Instructor and Blogger

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Shawn Tierney

Shawn began sharing automation news and know-how online in 1996 when he launched his first BBS. Then in 1999 he moved to the internet launching, which he later renamed In 2013 he moved his automation efforts to a new website,, which has since become the most popular independent industrial automation blog on the web.

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