This has been addressed in detail on this and other Forums, but it is a common issue (I went through it just last week) so it's worth working through for our new member
electric_man.
First, let's verify: are you seeing a question mark with or without a red X ? The red X always indicates a total communication failure and all the EDS files in the world won't help until you get the wires or network fixed.
Second, the path. Are you connected using RS-232 to the serial port of the ControlLogix 1756-L62 controller, or are you connecting through an Ethernet or other network module ? If you are connecting over a network, you need to update the network module EDS files as well.
Third, the revision. Do you know what revision of firmware is running in the ControlLogix or the network modules ? Usually you can right-click and select "Properties" in the RSWho browse to find out.
Fourth, the easy way: right-click on the network module or controller in the RSWho browse and check for the option "Upload EDS File". This is a feature of network modules/controllers/RSLinx that is 3 to 4 years old and makes uploading/registering EDS files foolproof.
Fifth, the hard way: Download the EDS files from the Internet and Register them.
To download the EDS file for a 1756-L62 version 16 controller, for example, start at the EDS server:
http://www.rockwellautomation.com/resources/eds/
Choose "Network Independent", catalog number "1756-L62" and Major Revision 16. You will get just one result. Download the file to someplace like your desktop or a working directory:
IMPORTANT: All of the EDS files are stored in the \Rockwell Software\RSCOMMON directory. Do not save your EDS file directly to that directory. Do not perform an EDS Registration operation on any file in that directory.
Last step: Run the EDS Hardware Registration Tool. Start->Programs->Rockwell Software ->RSLinx ->Tools ->EDS Hardware Installation Tool.
Point the installation tool at your EDS file, click through the prompts, and be patient at the end for 10-20 seconds.
Ta-daa. You should be able to go back and browse the network or serial link in RSLinx and "see" the proper icon for the controller.
If all this seems really complex, remember that every new release of RSLinx Classic includes a whopping library of EDS files for old and for new products. If you are running RSLinx from 2,3,4,5+ years ago you won't have the EDS files for new controllers and modules. That's why an update of RSLinx Classic Lite is often the easiest thing to do, though it's a monstrous download because of those big EDS archives.
This is also why the "Upload EDS File" feature is so handy. All ControlLogix controllers and network modules have supported this feature for several years.
