To Upload or To Download

castlerock

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Join Date
Oct 2005
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Does anyone have any idea why the terms upload and download are backwards when talking about plc's ? Uploading has always been to send a file and downloading has always meant to retrieve a file from a remote computer. If I send my program from a laptop to a plc, that would be considered uploading on any other platform.

The definition of both are here

The first time I used LogixPro I looked hard for the Upload button to upload my program. There was none. Is it just AB who has reversed these terms or do other brands do it too ?

I've only been learning this subject for a couple of months and this is taking some getting used to.


Thanks,

Mike
 
Ask yourself a question . Which is the "master" device and which is the "slave" device when we are talking about a programming environment ?
Check again , I think you may be getting a bit confused !
 
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10baseT said:
Ask yourself a question . Which is the "master" device and which is the "slave" device when we are talking about a programming environment ?
Check again , I think you may be getting a bit confused !

Programming environment has nothing to do with the terminoligy of networking. Its which machine initiates the file transfer and which direction it is going.

But I think I see where you are going with this. When I click on download in RSLogix, RSLogix isn't initiating an upload but its telling the PLC to initiate a download. Correct ?
 
castlerock said:
Does anyone have any idea why the terms upload and download are backwards when talking about plc's ? ...

Is it just AB who has reversed these terms or do other brands do it too ?

Hello Mike,
Most brands of PLC use the term 'upload' to mean transfer from the PLC, and 'download' to mean transfer to the PLC.
I'm not certain of the origins of the terminology however.

As far as 'backwards' when talking about PLCs, programs were being uploaded and downloaded to PLCs (in the fashion described)long before such things as the WWW or FTP servers and the like even existed.
 
Which one is the source and which one is the destination ? , a programming environment has everything to do with the terminology -which is the master , and which is the slave ?

Can S7 / Logix / Omron processors send their program to a programming device of their own volition ? Which device initiates the transfer ?

At the end of the day , my opinion is not so important - I may be wrong , but I think that all of the major PLC manufacturers tend to adopt the same terminology in this case - though I'm sure someone will tell me otherwise .

If it is any consolation to you , whenever I use yet another weird and wonderful programming platform for yet another brand of PLC , then I always make quite sure that the manufacturer means what I think he means .
 
I agree with Castlerock on this one. I come from a DCS background and was used to the other terminology. It took me a while to adapt when I first met PLCs - it certainly caused some confusion at first!
 
davegr said:
I recall that the GE series 6 programmer used the terms the other way round (very helpful!).

Logicmaster 6 (LM6) uses the terms 'Load' and 'Store', if you are downloading to the PLC you would 'load' your program from C drive then 'store' the program to P (CPU), to upload from the PLC you would 'load' from P and 'store' it to C.

Paul
 
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Paulus said:
Hello Mike,
As far as 'backwards' when talking about PLCs, programs were being uploaded and downloaded to PLCs (in the fashion described)long before such things as the WWW or FTP servers and the like even existed.

I hope I wasn't misunderstood. I didn't mean 'backwards' in that I think its wrong, just different from what I ( and many others ) are acustomed to. I was sure someone here could explain it.

Before everyone and his brother was using the internet I ran a BBS and used them for a number of years before that. The remote computer would download when receiving files and upload when sending files. It's just always been this way in any type of networking I've been exposed to. ( networking meaning anytime more than one machine are connected for data exchange...regardless of the type of connection or protocol used )
 
castlerock said:
I hope I wasn't misunderstood.

Before everyone and his brother was using the internet I ran a BBS and used them for a number of years before that. The remote computer would download when receiving files and upload when sending files.
Hello Mike,
No - no misunderstanding!
I too used to use BBS's many moons ago, and I could never get my head around the fact that I had to download to recieve stuff, and upload to send it. :confused:
Some of the guys here are software developers (little or no PLC experience), and they find it hard when using the "PLC definition" - I guess it's horses for courses really.
🍻
 
Personally I like the way Directsoft has it termed. "Save to Disk" or "Save to PLC" and "Copy PLC to Disk", or "Copy Disk to PLC", that's pretty clear.

Personally (no matter what everybody else goes by), I Upload to the PLC, and Download from the PLC.
 
10baseT said:
Which one is the source and which one is the destination ? , a programming environment has everything to do with the terminology -which is the master , and which is the slave ?
These are just a few of the things I will have to get used to I'm sure. Master-Slave or Client-Server. I've always thought of a programming environment as being an operating environment and a set of tools, or perhaps an IDE such as the ones that came with Turbo Pascal or Quick Basic. ( IDE = Indegrated Development Environment ) And in Linux/Unix it would be bash or csh, a text editor such as vi or emacs, and some command line tools like gcc and gdb. I may upload source code to a CVS server but it's not part of my programming environment. PLCs are just a differnet animal i suppose. -g-

10baseT said:
Can S7 / Logix / Omron processors send their program to a programming device of their own volition ? Which device initiates the transfer ?
Thats why I included the wikipedia link. The definition didn't include anything about client-server ( or in this case master-slave ) but only remote and local and direction of transfer.

10baseT said:
At the end of the day , my opinion is not so important - I may be wrong , but I think that all of the major PLC manufacturers tend to adopt the same terminology in this case - though I'm sure someone will tell me otherwise .
Ahhh...but your opinion is very important. Thats why i asked. Not only did I think that someone could answer my question but also that it would make for some engaging conversation. =]

10baseT said:
If it is any consolation to you , whenever I use yet another weird and wonderful programming platform for yet another brand of PLC , then I always make quite sure that the manufacturer means what I think he means .
Considering the other posts in this thread, thats a wise idea.


Thanks,

Mike
 
elevmike said:
Personally I like the way Directsoft has it termed. "Save to Disk" or "Save to PLC" and "Copy PLC to Disk", or "Copy Disk to PLC", that's pretty clear.

That makes a lot of sense. In peer-to-peer networking that is essentially what happens. When i drop a file to a shared folder on my sons computer here at home, its not an upload or a download but merely a copy operation.

elevmike said:
Personally (no matter what everybody else goes by), I Upload to the PLC, and Download from the PLC.
Sounds like you did some form of networking before you got into PLCs as well.

I'll be happy to adjust terminoligy when talking PLCs. But I always have to ask the question...why.
 
How's this for an explanation?

If I'm writing the PLC program on my laptop, I'm in charge of that progrom. I'm the boss. The boss' office is in the penthouse, not in the basement. So when I (the boss) send the program I've created to the PLC (the subordinate), the program is going from my office in the penthouse to the PLC. The path from the penthouse to wherever the PLC is located is downhill, so naturally, that's a download.

Conversely, if I want to check on the program that my subordinate is running, I invite that subordinate to "come on up to my office", in other words, upload.
 

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