I am in Perth.
I am not familiar with the IFM 300 flow switch, but follow the link to a data sheet for a flow sensor, it has a connection schematic at the bottom.
http://www.ifm.info/ifmaus/web/dsfs!SI5000.html
You can back track the link to find other IFM stuff.
Unfortunately, I don't use any of the other brands, so I don't have handy links.
Good luck, but your employer may need it more than you. I find this place normally goes crazy just before the end of the financial year. BTW, did you notice that Australia seems to have been totally cleaned out of DC circuit breakers? If you haven't got any, you may have to redesign your equipment to use fuses.
Doug