How to setup RSLinx and download to a PLC-5 via Serial

So you need to know how to setup RSLinx Classic to communicate over serial with an Allen-Bradley PLC-5 so you can download or go online with RSLogix?

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

Prerequisites: Before you begin, first insure your PLC-5 has serial port (not all do.)

Specifically, the new platform PLC-5/11, 5/20, 5/30, 5/40, 5/60, and 5/80 all have a 25 Pin D-Shell Serial Port.

Note that the 9 Pin D Shell on the PLC-5/10, 5/12, 5/15, and 5/25 is not a serial port but instead internally tied to the DH+ terminal block.

Next, insure you have the RSLogix 5 programming software and either the 1784-CP10 or equivalent Null Modem Cable. If your PC does not have a built-in serial port you'll also need a USB to Serial converter.

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 PLC-5 into it:

Step 6) Now click on Auto-Configure. If your cables and PLC-5 are in working condition, and your PLC-5 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 and after a few seconds you should see your PLC-5 appear under the AB_DF1-1 driver as shown below:

Step 10 Now open RSLogix 5, and then open your program file:

Step 11) Next, from the Comms menu select System Comms:

Step 12) In the popup Communications window expand your AB_DF1-1 driver and select your PLC-5:

Step 13) Then to download your program select the Download button:

Step 14) Confirm you would like to download the current program you have open into the PLC-5 you are connected to:

NOTE: The PLC-5 can only hold one program at a time, and downloading to it will erase the PLC-5's currently loaded program. If you do not have a copy of the current program loaded in your PLC-5 you should first perform an upload and save.

Step 15) Next, if the communications settings in your offline PLC-5 file are different than the settings you are currently using you will receive a notice asking if you want to save the current setting to your offline project file:

Step 16) At this point if the Controller in your offline project is different than the one you are downloading to you will be asked to confirm the change and resize data tables:

Step 17) And if the PLC-5 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 18) At this point if you made any changes to your program you may be prompted to save it:

Step 19) At the end of the download process, if you still have communications with the PLC-5 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 a pop-up giving you 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 PLC-5, and then how to download to the PLC-5 using RSLogix 5 was 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 (post views: 6,889 views)

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Forum Comments:
  1. I'm trying to go online with a customer's PLC 5/40. When I configure my driver in RSLinx Classic and click on auto-configure it times out without negotiating a connection. I'm using a null modem cable with RS232 to USB adapter and have successfully gone online with other PLC 5/40's at this site, so I can only assume that this particular processor was set to ascii instead of the default DF1. This is the first time that I've encountered this issue and I don't know the proper driver configuration to use. Any help would be appreciated. I don't have a saved offline copy of the existing project so I need to upload from the processor and go online to troubleshoot some issues with the conveyor system that it controls. Thanks
    Good morning ,
    Could be a few different things, including the port isn't set to System (Point-To-Point)
    First thing I would do is open the offline file and check the settings of channel zero, then set RSLinx to match if possible (assuming it's not ASCII)
    If that didn't work, I'd try auto-configure on another PLC-5 just to be sure the cable still works.
    And if the cable still works, but the settings if the offline file don't, I'd try to connect over DH+ to see what the serial port is actually set at (I'm assuming you can't pull the controller to insure the port is set to RS232?)
    Hope this helps,
    Shawn Tierney,
    Instructor at
    I have a problem when i try to download or upload, i can see the PLC5 1785-L86B/E in RsLinx with a Data Highway Plus, but in the moment when i try to download/upload in RsLogix show this "Diagnostic Status failed Sts = 0x05 Application Layer Timed Out ( No Reply )". Can you help me
    Good afternoon @dax_hammer,
    Can you confirm the PN#? Do you mean a 1785-L80B/E?
    Also, is the PLC-5's key in the RUN mode?
    Another thing, if you are downloading over DH+ it might be your network is out of bandwidth - have you tried locally via the serial port?
    Something else to check is this tech note (I don't have a tech connect so can't see it:)
    Shawn Tierney,
    Instructor at
    thanks for response, actually i'm connected with 1785- CP10 via serial, but automatically use a DH+ driver. The procesator is ib program mode and the part# 1785-L86B/E vK
    im thinking about the version of the RsLogix is not the correct, im using 8 version
    Good morning ,
    Ok, that makes sense as I've seen that error using serial before - does the "auto-configure" correctly find the settings? (do they match what's in the offline file?)

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