PIR + WebControl PLC Controller

First off - Thank you all in advance - this is my first electrical project(I'm very confortable with electronics - but this is the first real project I'm putting together) and your time and assistance would be greatly appreciated.

I've got an interesting problem... monitoring the usage of the restoom at work. We have probably 60-70 employees sharing 2 restrooms (1 mens / 1 womens) as well as many others from other floors (our sales department likes to visit... something about a single stall). Anyways - so as you can imagine its quite common to get up and go over to the restroom (which is down the hall) and find out its occupied. This gets old when it happens 3-4 tmes a day. So - surely this can be automated right?

I did some searching and found a similar project online called the ipotti - http://stuffandymakes.com/2011/03/03/ipotti%E2%84%A2-released/
Basically this guy has a similar issue and solved it by monitoring the status of the lights in the bathroom - to an ethernet controller that his office Mac's check.

This is essentially what I'm trying to accomplish - although we have a lighting system in the building and we cant be turning the lights on and off a hundred times a day so I had to come up with a different option for determining occupancy. I figured the next best thing would be a PIR to monitor occupancy right? I know i could try and monitor the door and what not but i think that might be hard to make accurate - since you might have someone exit and enter at the same time.

I remember reading quite a bit about the WebControl PLC boards on cocoon some time ago and per the documenation below the aux input has analog and digital inputs you can monitor - in addition to temp/humidity sensors. My thought was to connect the PIR alarm contacts to one of these analog inputs. The documentation indicates I should be able to use GET/WGET to read status of input and output. So i went ahead and purchased the WebControl and a fairly cheap PIR - Optex RX-40PI. The end product I'm hoping for will be a Windows 7 Widget that queries the Webcontrol status of the analog input (0 or 1) for occupancy :) At least that was my thought.

Ultimately where I'm stuck now is i figured I could just attach the alarm contacts of the PIR to the analog input on the WebControl board but now I'm not sure - the PIR says 'N.C. 28V DC 0.2A max.' on the alarm output - which i know is normally closed but I'm stuck on the 28v DC statement.. I had assumed Pin 4 (GND) and Pin 1 (input 1) - can anyone confirm I'm reading that correctly? are the voltage statements cause for concern?

The WebControl says the analog inputs can range between 0-10vdc - so will it not work with this PIR? I'm sure this is a simple question but i'd rather not burn up a $35 WebControl panel by overlooking something this simple. If this PIR isn't going to work can anyone recommend on that will? What should I look for?

"The AUX input connector offers digital and analog inputs that can be configured to
set a TTL output upon a single input or a combination of inputs. 3 analog inputs are
offered that have an input range of 0 – 10Vdc."

WebControl Manuals

PIR Manual

Thanks again
The voltage rating on the PIR is what you could pass through it's contacts. It should be a non issue for you as you will use considerably less. While I am not familiar with the WebControl board (I should get one, looks cool), you pretty much just want on/off (boolean) status so I would likely just wire an input on the WebControl with either a pull up or pull down resistor.
A PIR might not give an exactly accurate status depending on the layout and the "activity" in the restroom.

Why not use relay wired off of the lighting to get your signal. Of course, this requires everyone to turn off the light when they are done but a motion might not give you an indication when people are seated and not moving much.
First off - thank you for those that have commented. I know that the PIR might not be 100% accurate as far as activity goes :) but if it becomes a problem i think i could use the PIR as an input and use the PLC logic to lets say keep one of the inputs tripped for 30 seconds etc.

As far as wiring goes - I think i'm understanding this, so the Webcontrol analog inputs can handle 0-10vdc, and the PIR can handle voltage through the alarm contacts of up to 28vdc. So I had assumed i would connect the 2 alarm contacts to the webcontrol (pin 1 for input 1) and pin 4 for ground. Does this mean i would connect voltage - lets say 9vdc negative (-) to pin 4 on the webcontrol and then 9vdc positive (+) to one of the PIR's alarm contacts, and the other alarm contact would go to pin 1 on the webcontrol? so the webcontrol would see a change of 9vdc?

Does that make sense?

It also looks like the aux in on the Webcontrol board shows that Pin 13 supplies 5vdc, could I use that for the PIR alarm contact and then the other PIR alarm contact to pin 1 (input 1)? That might be easier since power is supplied directly.

Thank you again for the comments and advice.
Ok - Quick update on my project. I sucessfully tested the configuration I was hoping for and it works great. I have the PIR's contacts (normally closed) connected to 5+VDC and the other to one of the boards digital interfaces. As expected the PIR trips momentarily when motion is sensed. I wrote a small PLC script that when the PIR trips the input it sets one of the outputs open for 60 seconds - I figure I'll need to play with that time depending on how accurate it is :)

A friend of mine is working on the Windows Widget ... should be a slick setup when its all said and done.