jstolaruk said:
Well, you challenged my statement, you might as well cough up your reason for calling it nonsense. I may learn something about S7 that will help my efficiency debugging. ☯
OK. Here goes:
Since long, the PLC memory itself is no longer the scratchpad in which instructions are inserted one by one when the programmer presses keys on his handheld terminal.
Today, you edit the program on a PC and it is downloaded to the PLC.
On AB, you edit one rung at a time, and when you hit the ENTER key, it is downloaded to the PLC (*).
On Siemens, you edit a complete block at a time, and you have to manually initiate the download of the block to the PLC.
Point: Technically AB and Siemens are not so different behind the scenes. One is not more online than the other.
Arguably, AB gives you a more fluent feel when programming, you dont have to do so many keypresses or mouseclicks in order to achieve the same.
However, ABs online editing could also be improved. It has hit me uncountable times, that I forget to move the cursor to the start of the rung and then activate the green tickmark to accept the edit. When I then later "test" and "assemble" my edits, some rungs are not included. Someone mentioned that there should be an "finalize all edits" button. I aggree to that.
Point: AB and Siemens are very different. AB may have a slight lead in the productivity department.
I think that this is what you mean to say, that it is a more of a hazzle to do edits with Siemens than with AB. I aggree, but the reason you state is not correct. I also think that if you sum everything up, the difference is not so great.
AB has a genuine advantage over Siemens due to the test and untest feature. No other PLC that I know of has a real undo/redo functionality.
*: You can also insert one instruction at a time, but what really happens is that the entire rung with the new instruction is downloaded and replaces the old rung.
edit:
I shouldnt have used the word "nonsense". However I see sometimes the statement that Siemens is "not really editing online you know" used as a way to derate them. Thats why I felt I had to correct you.
I could have said "ABs online view is not really correct you know". And we dont want to start an argument about that, right ?