I've ever heard about the Upload function of the Allen Bradley PLCs and I wonder what it's really allowed to do.

Could someone explain me what is possible with that function and what's not?

Thanks a lot in advance.

 

Upload means copying the program from the PLC processor to a computer connected through the comm. port. Uploading will allow to have a copy of the PLC program in the computer. The only drawback of the upload is it doesn't have the descriptions for the instructions and rungs in the PLC program when we upload the program.

 

This function allows you to upload the current PLC program along with the variable values and I/O status. You'll also get the PLC status with the upload. This feature does not upload the variable descriptions, as they are not stored on the PLC. If you have the variable descriptions you can import them into the uploaded project. Note: some PLC's will not allow the upload funtion. There is a setting (made on the download) that requires a copy of the program be present on the computer attached to the PLC before an upload can occur. Some machine manufacturers set this feature to protect their software from tampering.

 

Um, well, you "upload" code and data from the PLC in which they reside to the programming software running on your PC. You can monitor online operations with a live ladder view and real time data table views. You may have a hard time understanding the program as documentation for ladder and data points is not stored in the PLC, so it may be hard to troubleshoot the program if there are problems. You will be able to save the file on your PC, which will act as a backup copy in case the PLC ever dies.

 

One thing I noticed wasn't mentioned is the database. When you upload the program onto your PC, you will get the rungs and addresses. While this is all good to back up a program, the database is what will tell you what each input, output, integer etc. actually is. I have a ton of AB PLC's in operation and make it a habbit to export the DB (I prefer .CSV format) into a gang file. This can then be imported into the new file created by the upload. By doing so, I can go back on line with the PLC with all descriptions in tact.

To export the DB in RSLogix 500, go to the tools tab on top for the drop down menu, to the database tap. You will see ASCII Import and ASCII Export. I preser CSV format, so after clicking ASCII Export, I use the CSV tab. From there, I check the boxes for addr/symbol desc. and instruction comments and hit OK. The file will be saves in a microsoft excel comma seperated values file. This is important to do if you purchase a machine with an AB processor and are furnished the DB on CD or disc. Once you have the program uploaded, click tools, database and ASCII Import. Check CSV and import all. You then select the file for the DB and import it. This will save a huge headache in the future...