We have a handful of these on service (none on my route), and they all have the same problem, on a fairly regular basis they end up buffered out in the pit or overhead. These are units in different buildings, different cities, different ages, different machines, operators etc. Everybody has kind of given up on figuring out why they all do this because someone heard about some kind of magic software upgrade that they need from Kone. Anybody know about the software upgrade (if it exists) or what makes these units prone to this problem?

Your ETS Switch needs to move closer to the floor. If the Print says it should be at 1'-8", place it at 1'-5". What happens is you are making an NTS stop for whatever reason, but you end up ETS stopping instead. To check that this is the problem. Set your Service Tool up for a Buffer test in either direction, but don't jump out any switches. You will most likely Buffer out. Then move the Switches and repeat the Buffer Test. You should make a regular NTS Stop.Good Luck

Not sure about johns theory, but I've got a number of these on my route all from the early 90's and several of them based on the KONE service/call back records left behind suffered this same "buried in the overhead" trouble. A software up grade was the fix for these troublesome units. Again, all based on information left behind at different locations.

I don't really know why Software would fix a problem like this. NTS and ETS are backup Switches. They operate independently. When all else fails these should stop the Elevator. When performing a Buffer test and these Switches are jumped out, you slam into the Buffers. When they are left in the circuit and you perform a Buffer Test, they should stop you at or near the floor. So it may be worth a try before paying for a Software upgrade. You can move a switch in 20 minutes.

While I am unfamiliar with this type of control, I am used to NTS and ETS on others. In my experience both these actions are backups to 'normal' s curve slow down and stopping. So I would also check why this isn't happening. NTS/ETS are also supposed to pull the lift up to floor level as well albeit harsher than normal. I have had it where lifts have gone thru the overtravel simply because the momentum was to great for these failsafes to work to operate in time, which is another thing to check.

been seeing this for many years now, have done many things over the years to try and solve this, to no avail. the strange thing is that when you find the car in the pit or overhead, it is always empty, i have never had to get one out of the limits with someone in the car. I'm sure it happens, but for me over the years the car is always empty. not sure if it is a software issue or what, but it is definitely an issue. we just took over 9 of these a year ago or so, and most of them have been in the overhead at least once or twice, never occupied, have replaced position encoders, motor encoders, adjusted ets and nts switches, replaced M contractors, replaced all relays, etc etc etc still same outcome. they just show up in the overhead or pit, very strange i don't think they are not slowing down properly and shooting thru nts and ets , but they are usually buried a good distance past the floor, never just a 1/2 a foot or so. i could swear they are at the top or bottom, and just accelerate in the wrong direction. 90 percent of the time the cars are in the overhead. i used to think that the M contactor was not making or the speed command was not working, and the car lifts the brake and drifts into the overhead, but it is usually so far into the overhead i can't see this happening. someone out there must know something about this scenario

Vatorgator, route mechanics have tried all off those thing that you mentioned, with no success. Also, cars are never occupied and never just a little past the floor, they are buffered out.

I have seen cars do the same thing, I once caught one doing it. It tires to leave the top landing, picks the brake then drifts up. It will do this until it reaches the limit.

I believe there is a software upgrade for this problem. It has to do with the dispatching. The car tries to answer an above call and drives itself into the overhead.

Just in case anyone looks at this post in the future, the software fix applies to the AC drives only. You can get it from Kone or Cetek, they call it target chasing software. It chases some phantom call on the ten thousandth floor or something in the middle of the night and the software will fix it. But the DC drives do it too and it could be anything as mentioned above.

I had this problem constantly on 2 Miprom 21's out of a 3 car group. They had Digital DC Drives, we would get entrapments in the overhead, car stuck a few inches above the top floor, etc...

We found a loose INR wire (it was the inspection circuit-not sure if its called INR but I think so), that wire was loose- all the way at the top of the controller with all those bad terminal blocks.

We tightened that up problem went away- we also put a toggle switch there to make putting car on MR inspection easier.