Set Default Digital inputs to Low? How? bad Analog value?

[Generalx5]

The sensor belongs to OPTEK technologies, OPB742D and OPB606A are the two sensors Im using.

Here are the Sensor Data,

http://www.optekinc.com/pdf/OPB740.pdf

http://www.optekinc.com/pdf/OPB606a.pdf

The voltage picked up from my Multimeter reads DC 0.4V maximum using a 1.5V double A battery source.

----------------------------------------------------------------------------------------------------------------------------------
Also, in hopes of getting rid of the use of Inverters, I've tried instead of setting INPUT; at the end of the IO's, I set them to 0;

IO4 = IO5 = IO6 = IO7 = IO8 = IO9 = IO10 = INPUT; <---------Before
IO4 = IO5 = IO6 = IO7 = IO8 = IO9 = IO10 = 0; <---------After

And I'm still not sure if it works, although the voltage between SIG and BLK is gone, I havnt found a way to trigger it so it goes high.