Multi User
Quote:
This is an interesting capability and I think people don't appreciate how good and terrible this feature is at the same time and how different platforms approach this capability.
It's not just 'interesting' it's absolutely essential & with competent teamwork there's nothing 'terrible' about it at all.
Consider this machine, a single work cell contact lens tray transfer system with a 1756-L72S ControlLogix PAC & a Mitsubishi robot:
https://www.youtube.com/watch?v=2XZBidLM-yI&t=30s
I was assigned to program the rotary inverter & the tray pick & place. Another colleague did the Mitsubishi robot interface & FactoryTalk SE HMI. Another programmed the robot itself. We therefore had specific routines to work in. If there was a question or concern about an online edit you simply ASKED. You make such a big deal of this that I can only surmise you don't architect your programs logically, divide your tasks well or that you have interpersonal communication issues. Since simultaneous editing became a standard feature around 2005, I've never had an issue with this. All it takes is proper planning & communication.
Without simultaneous online editing it would have literally at least twice the engineering hrs. for commissioning, debug & FAT.
Now, take another project I worked on, a 12-cell machine that assembled residential water filters. This machine had a 1756-L85E, an L72S (the safety partner for the 85E wasn't out at the time) with 4 Ethernet/IP cards, 1 for HMI, 1 for I/O, 1 for servos & 1 for safety. It had 5 Fanuc robots, dozens of servos, SMC pneumatics, Cognex vision systems & a massive SE HMI with thin clients. It was routine to have FIVE controls engineers online editing concurrently on different work cells. Unless you write perfect code ahead of time I don't see a better way of accomplishing a startup such as this. Do you?
I'm also baffled as to why you think having the master copy of the program on the PLC is such a horrible thing.....unless you don't realize that all of the comments, symbols & descriptions are there too. Anyone with Studio5000 & an ethernet cable can walk up to a ControlLogix PLC & upload a completely documented program. This has been true for years. I also back up daily to the network.
Finally, as to how B&R does it, I.don't.care. Companies I work with have controls specifications that require either Allen Bradley or Siemens. In 25 years of doing this, I've run into exactly one company that uses B&R standard & that's Krones. And they only use them because their servos are cheaper. Siemens PLC's are still the masters in their machines. Not to mention the fact that PowerLink is an utter joke of a network. They still use HUBS?! Ask the Communist Chinese how standardizing on PowerLink is working out.
Have a nice day