Being a rented condo you should ask the owner what can and may be done.

We will get the owner's ok. In this case my daughter is very good friends with the owner so it should be no problem.

Ginny

You can use a wood spindle that allows the door to only be opened the space you want. Open the door, measure the space from the door to the opposite jamb and cut the wood. It just lays on the frame bottom so there is no change to the door or frame.
Ron

Ron I think you are talking about putting a piece of wood (a dowel?) in the track but the track is on the outside.
Ginny

A much more secure idea is an insert that contains the pet door but allows the sliding door to be locked.

Here is a link that might be useful: Lockable pet door insert

Cut a broom stick to fit in the track. Another option, I went on vaction once and bought these

http://www.doorandwindowparts.com/home-security-hardware/window-security-locks-and-devices/thumb-turn-sash-locks/sash-lock-sliding-window-mill-2-pack-1.html

My 2 hour flight handn't even landed yet and my crazy downstairs neighbor called the fire department saying water was dripping from their smoke dectector and it had to be my aquarium.

I came home 3 days later to find that because the fire department couldn't get in the two sliding glass doors, or the two slider windows in the bedrooms, they broke the bedroom window only to find my aquarium was fine.

"Cut a broom stick to fit in the track."

How many times is the OP going to have to post " the track is on the outside"?

The door really sounds like it was installed inside out, and then the locks simply reversed.

Not a good install (likely to leak) and cause problems trying to secure the moving slider (even fully closed and locked).

Thank you all for your help with this situation. I will send this to my daughter and let her figure it out with the owner.

Ginny

The track of a sliding door would be on the inside unless the door was installed backward. If the operating panel is on the outside, it could too easily be levered away from the other panel and popped out of the top and bottom tracks so the door would be unlockable (if that's a word). This is more serious issue than the cat problem. Your daughter needs to get a lockable door and then use a stick in the track to allow it to open a small amount.

You can drill a hole, approx 3/16" dia, through the track and into the frame of the slider when the door is open the desired width. Then use a bolt, pin or other to secure the door in that position.
Drilling completely through the door is not necessary.
Make sure you are not in the area of the wheel mechanism when drilling. This works at the top or bottom of the door.

What Randy427 suggest is what I would do, it is not complicated and can be done in a few minutes .
No need to hire someone for this .

Thank you once again for even more great ideas. I'll send them on to my daughter. We are going to have a locksmith out tomorrow to asess the situation and give his ideas. She will then either have them done, or if it is easy, do it herself.

It never ceases to amaze me how wonderful people are on Garden Web. Over the years I've asked questions many times on different forums and gotten great help!!

Have a wonderful day all of you!

Ginny

While you're at it ask the locksmith to address the security issue of the vulnerable outside operable panel. Personal security should come first, then the cat.

Doesn't the handle strike the fixed door panel when the outer panel is fully open? How does the screen clear the outside handle? Is the screen on the inside? That would be a pretty funny.

I'd love to know who manufactured the door and what the locksmith makes of it.

To add on to what macv mentioned about security, I will also point out that sliding doors can typically be lifted up and out of their tracks, particularly when the existing lock is not engaged, unless they have the 1" space above the door fitted with a couple of screwed-in spacers or bumpers; whether they do varies from manufacturer to manufacturer, and/or how responsible the installer was. The fact that the door can be de-mounted is great if you need to do some maintenance on it, but it's also great for burglars. A sliding door on the outside has the potential to be even more vulnerable to this kind of mischief.

Depending on your particular door set-up and on what type of solution you come up with to your original problem, make sure this issue I've described is either not a problem or is taken care of.

It amazes me the extremes folks go to "secure" patio doors/sliders when the bad guys wanting in bad enough will simply break the glass. Same with windows. Outside of making your house look like a prison with wrought iron everywhere, the simplest solution is to have a reputable securty system/alarms. Randy has a good idea for a simple stop system for the op's situation, but it wont keep the bad guys out if they want in bad enough!

Breaking glass is not only dangerous, it makes enough noise to alert neighbors so it is rarely the preferred MO of a thief. And it's not difficult to get through a locked window or door especially one that slides.

sierraeast-
With patio doors the glass is typically tempered and/or laminated, so breakage for entry is not such a big issue. From my experience, patio doors are susceptible because they often have feeble original locks and can sometimes be lifted out of the tracks. I agree with you that you can't make your house burglar-proof, but you can make it harder for them. In fact, I'm a belt and suspenders guy: I've got a supplementary lock on my sliding door and an alarm system!

Many moons ago we were doing lawn maintenance in a neighborhood when the police showed up across the street. Appearently in broad daylight, the daughter sleeping upstairs with mom & pop in the backyard, a bad guy (s) entered the front door and got away with valuables from the front room. If it's going to happen it will but you do want to make it as difficult as possible. Most bad guys will pick the easiest target, but breaking the glass is common for those who are desperate. I dont think safety issues cross their mind!

Usually simple flush bolts will work but when the panels are reversed you need to use keyed locks near the opening side.

Just wanted to chime in - I have been shopping for sliders and some ARE manufactured with the sliding panel on the outside (Pella for example - marketed as a "feature" to better seal against wind blowing against the door) and the screen on the inside. Ridiculous.

Anyway - for this case I would suggest a removable pet door panel.

Here is a link that might be useful: Pet door panel

You could just use the automatic remote controlled device. A more advanced one should enable you to put the sliding door on stop at a position without closing it full.