RX3I Transfer Lists

[yorkiiii]

Hey all, I have a quick question about RX3i transfer lists. I was wondering if anyone knows the difference between the input and output transfer lists. I have seen systems where the input transfer list only includes inputs (%AI and %I) and the output lists only includes outputs (%Q, %AQ, %R, %W). I have also seen systems were every variable is included in both the output and input transfer lists. Does anybody know which is the recommended practice? Seems weird that on the input transfer list you can still specify output points and vice versa for the output transfer lists. Thanks!

 

[Steve Bailey]

Are these the data transfers between the two CPUs in a redundant system?

 

[yorkiiii]

Yes they are. I ended up figuring it out, pretty simple, the input transfer list is transferred between the redundant processors at the beginning of each scan, while the output transfer list is exchanged at the end of each scan. I can say that it works the same whether you put all variables on input and output lists or just input variables on the input list and output variables on the output list. You would only ever run into problems (possibly) if you were exchanging an extremely large program (all possible registers being exchanged every sweep). Thanks!

 

[Steve Bailey]

On a redundant system I converted from 90-30/Genius to Rx3i/Profinet, I neglected to include the %G memory in the transfer list. Unfortunately, there were a bunch of recipe options that used those addresses, set and cleared directly from the HMI. Fortunately I caught it when I tested the transfer from primary to secondary during commissioning.