Docedison:
Pull up's on all outputs and diodes cathode to output anode to common "Controlled" input, put a 4K7 pull up there too.
@ Mike an OC output is open... until it's activated or it's inverted and low until activated when it becomes 'open'.Bob
Judging from the example schematics they provide, the output is active high (so not NPN open collector) and possibly current-limited. I would use a 74HCT27 triple 3-input NOR gate to combine up to 6 of those PIR outputs into one 5V Arduino signal.