This can be tricky. I've successfully printed on my Encad, laminted, then put it on my $600 24" plotter with no electric eye and then cut.
Each plotter is different and you basically have to find the starting point of the knife and figure out how much it offsets when it begins cutting. On the print itself, you can make a dot with the measurements of where to start the cut line. Then in your cutter software, place the cut line only without the dot. Set your knife position and cut. It's not 100%, but it is pretty close and with a little extra space around an image of white or printed area, it works great.