mike ward Posted May 31, 2013 Report Posted May 31, 2013 Hi all I am used to programing Allen Bradley PLCs that have the test edit function. What technique do people use when with Step 7 to quickly get back to the original program when the modified program is not correct?
Groo Posted May 31, 2013 Report Posted May 31, 2013 Change it back or Copy code to parallel branch and insert test bit (M) or Save original to source for recovery In addition, create and download OB121 to stop crashes and afterwards remove from both off-line and on-line programs.
RH- Posted July 15, 2013 Report Posted July 15, 2013 Hello, I know AB Bradley well, so I can offer you this way of editing similar to AB. Open your project, and go online. Currently you will have two windows in your project manager (online and offline). So you can open functions in online project and make changes, the point is that you do changes and download it into CPU without saving into your offline project, so in case if you want to return, you just switch into your offline project and download function(s) which you have edited. (Sometimes when you close window in online it ask you to save it, don't accept it otherwise your backup will be compromised) Be careful about online edits when machine is running, although Siemens is capable to load your program without stop, it's not so user friendly as AB in case of syntax and program auto control as AB. (CPU can fall in stop) Best regards, Radek
Crossbow Posted July 17, 2013 Report Posted July 17, 2013 Test edits are one of those things that truly only exist in AB. Nobody else I have worked with does have that 'undo' feature for an online edit. I would comment out a rung by putting a dummy contact in front of it. Then add your new code. If it doesn't work, delete the new code and the dummy contact to go back to the old one.
Groo Posted July 17, 2013 Report Posted July 17, 2013 (edited) so 2 for "Copy code to parallel branch and insert test bit (M)" option then :) It would have to be a parallel branch rather than a rung as the coil at the end (if there is one) turning off could be effected. I have seen the view changed to STL and the code copied and pasted into the comment section of the rung which is later deleted or pasted back Edited July 17, 2013 by Groo
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