Hey guys I have a intermittent problem with a T4 overspeeding. I have changed out the motor encoder and the position encoder with another car. I also replaced all the opto isolators on the DSP card. I have verified that all dynamic braking resistors in the drive are good. I'll double check but I remember the codes being a 40,52,907 and perhaps a 10 but I'll have to recheck the order of those. The car will run a day or two or three before I find it out again. It has trapped people every now and then. Any ideas would sure be appreciated.

Is it actually overspeeding? Does the governor trip?

Yes it does trip the governor switch. I have ordered another DSP card. I had the local board repair shop replace the optos but maybe the problem is further back. We tend to find the car in almost the same spot in the hoistway each time. I read something about a software version that was sort of prone to this but it has not been a problem with the other cars yet. The position encoder looks great on my scope.

Ropes aren't slipping at all?

I have seen in some of my manuals that the position and velocity encoders have an external regulated 5 volt power supply that feeds the encoders. do you have these or is your 5 volt power supply coming only from the DSP card? you indicated you have changed the opto isolators on the DSP card, do these have anything to do with the 5 volt power supply being sent to the encoders? I would change the whole DSP card, if you dont have regulated 5 volt power cards to encoders.

The units on this job do indeed use the DSP card as the power supply for the position and velocity encoders. I am waiting for a new DSP card . That reminds me of a call I need to make tomorrow morning. Fortunately, the building is not full right now so one unit down is not really an issue.