RS5000 cleaning up program

Came across a line in program for robots at home, the second branch disturbed me is it possibly and why would you do this.
Seems like it would cause a incident if your telling the program the robots at home and it's not.

At first it looked to me like they were sealing in the command to tell the robots to home until the PLC receives both inputs back from the robots saying that they're at home...but no, you're right...

But after looking harder, it does appear the B000[54].3 address really means "Both robots home or either robot not homed..." or uh, well, nothing...the rung is forced on after once getting both robots homed, huh?

How about a new comment for the bit rung: "Sometime since the PLC entered run mode, both robots were homed at the same time..."

It functions like a seal-in circuit, but I question why they added the XIO contacts on the lower branch. It looks like it would function exactly the same with, or without those contacts.

As far as I can tell, the first time both robots are home, the 'ROBOTS HOME' bit will turn on, and STAY ON indefinitely. Of course, this is only a small snippet of the program, so that's all we have to work from. Search for the B000[54].3 address to see if it gets reset elsewhere.



-Eric

Only other bit is in the Auto Mode rung which allows the robots to start, so from what I've read from yall and looking at the rest the rungs the only time this will be off is first run. I guess if the plc lost the bit due to maybe a power outage then you would have to finish the robots in manual then rehome to put back into Auto. Makes since but the name they used doesn't so I changed to Sta 12 Robots Homed. At least it had a name I've found several that just have ?????.

Thanks for the help!