Pin numbers on RJ45 and DB-9 are the same

1 or/w  1 wire bus
2 or    GND
3 g/w   uSwitch (short to gound to indicate valve open)
4 bl    5V
5 bl/w  24V
6 g     uSwitch 
7 br/w  coil - plc pulls to ground to open valve
8 br    coil

(doubling up is to make wirign in plc neater)