Home Forums General Discussion Technical Questions Otis 411 NTC Sensor

Anyone know what is the function for the NTC Sensor on a 411? We picked up a job and all the controllers have the NTC input wire from the landing system disconnected. My guess is they are some kind of check for the NTT and NTB sensors. There is no operational description on the NTC input in any manuals. When the NTC wire is connected the elevator will get position errors at the terminal landing every time. Anyone have any ideas??

I think it has to do with the misplacement of the sensors. I can't remember, It was ten years ago, but think the controller has to see either the one in the software of the position count before the sensor in the shaft, or vice versa. I think I moved the sensor in the shaft. But something also kind of has me thinking that you can change the position count slowdown in the software to get the same result. This is just a guess at the moment from an old memory. I will dig through my manuals and check to see what that is.

I was thinking the same idea. The vanes for NTC are on the same vane as the NTB or NTT slowdown. It's a U shaped vane and one side is NTB or NTT and the other side is NTC. On this job (300 FPM) there are two notches int the NTC vane, so the sensor will go low two times as the car comes into the floor. Since the vanes are intregal, if you move the NTC vane it also moves your slowdown vane. I did try moving these up and down to see if we would have a different outcome but No Luck. Also went through all MCSS parameters to find an adjustment parameter still No Luck. This job came from Otis and they had these inputs disconnected, there must be a reason why.

I ask a dumb question. learn run? after you moved sensor. I think the count adjustments are in the hidden mcss parameters. I again, will have to look for the hidden menu command in the manual. Later today I should be near my office.

Was this a moded otis ..something got moved to sofrware if it is ..

Yes, I performed a learn run after each time the vanes were moved and made no difference. This job was modded to 411s about 3 years ago.