Backup from a PLC running a process

The issue with a controller programmed using RSLogix 500 is that the rung comments and descriptions don't get sent to the CPU. That information only exists in the RSLogix 500 project files. So when you upload from a PLC to a blank project file all you get is the ladder logic.

Thanks Steve.
That cleared a lot of my doubts.
Now is it possible to get atleast a printout with all the descriptions? Or even that is not possible?

Thanks once again.

If you already have a copy of the RSLogix 500 project file that includes the rung comments and variable descriptions, you can make a printout that includes them.
If you are starting from a brand new project file and uploading from the PLC, you won't have any comments or descriptions to print.
Someone mentioned in an earlier post that if you have an old copy of the project file and you uploaded from the PLC into that project file you run the risk of the comments not properly aligning with the rungs. That could happen if someone edited the program in the PLC between the time when your old copy was saved and the time when you uploaded from the PLC.

Thanks Steve.

No I don't have the original program. If I had that I wouldn't be trying this hard to get what is inside the PLC.

Now that its very clear that if I am uploading afresh, I won't get anything more than the the bare ladder logic. No comments at all.

Isn't there ANY way to get the descriptions if one doesn't have the original program?

Thanks Steve

That's correct, you will only get the code and the states of the bits & registers as they are at that time, If you download the program some internal bits will be in their last state, however, I/O will update that within one scan so if an Input is off then after I/O update it will be off from that point, however, latched internal bits may stay on if the logic that would reset it is not true.
Upload of a program to your PC will not affect a running process but just be aware that registers i.e. N7:xx will be forced to the value when you uploaded it, it will be set to the current value in the PLC if the code is true on scan so for an example:
Lets say you uploaded registers and N7:0 was 1234, then when you download the program it will be forced to that value, however, if the logic is such that it was writing continuously a value of 5678, then when the program runs that bit of code it will force the value back to 5678.

Thanks Parky.

Thanks for making it crystal clear. So Isn't there a way to upload comments even for pros like you when you don't have the original program?

Thanks once again Parky.

Noob:


The answer is no.


TL;DR.



If you no longer have any offline copy of the program, then no, the comments and descriptions are gone.


If you did have an offline copy of the program, then, as you noted yourself, you would not be asking this question.


You can test this with a spare PLC:

• write a simple program e.g. toggle an output at 1Hz;
• add comments and descriptions;
• download the program;
• set the PLC to run;
• close the program in RSLogix;
• you are now in the same state as with the real PLC
• upload the program from the PLC while it is running

There will be no comments or descriptions in the ladder diagram.


I don't know about RSL500, but on my system (Micro Starter Lite), under the [File] menu button there are options to set [Report Options...], to do a [Report Preview...], and to [Print Report...].

Thanks drbitboy,

Nice explanation. So If don't have the original program, the descriptions are gone forever.

What is the export to .csv option under tools for? Relevant to this topic?

In future, when I do have the original program, what should be the way to upload a program. Please explain in order to complete the PLC backup education.

Thanks once again.

If you have the original program with comments then load the project into RSL500, go on-line & upload it, As I say it has been sometime since I used it but seem to remember it is a bit awkward, I seem to remember if it cannot locate the original file it asks you to select a file from the configured directory or upload it to a new one. you select the correct one and it will upload it, perhaps someone who has used it more recently could explain it.