Modicon Nuances Help

Hi, I have a general modicon help question. I am being given charge of a a Modicon system that has 3 modicon PLC's controlling drives, communications, and Furnace setpoints. Previous on Plant expert got new job and Im the guy they gave it to.

Since this is my first time using modicon (Rslogix 5000 knowledge only) What are some quirks of Modicon that a new person should know. I beleive the PLC's are (from project description) 984A/S 908 MBP-.2, 984-785L-MBP-.4, 984-785-MBP-.6

Any potholes that new modicon people should know would help me greatly

One would be how the program is scanned.

AB is scanned Left to Right-Top to Bottom

Modicon is scanned Top to Bottom-Left to Right

See PDF and link below


http://www.google.com/url?sa=t&rct=...x4CwBw&usg=AFQjCNGGUQPbQ_mRoWoSKZmUHhBbqM1inQ

That is odd to say the least, coming from control logix. I imagine it is an effort to emulate a relay setup closely. So the entire network could have logic lower in the page effect higher elements on the page if the output coil is placed farther to the left in the logic setup