MCE, IMC randomly latches car calls

I have an MCE IMC controller that randomly latches calls to the fourth and fifth landings. This occurs with no passengers, even with the controller on test.

These landings are secure. To access these floors, you push your desired floor and then press a sequence of buttons on the COP to latch your call. Before your call latches, your desired floor button flashes (for about 15 seconds) as well as the input LED on the HC-CIO board. When the "phantom" calls latch, there is no flashing, they just latch. On my group computer (not sure what MCE calls it) I checked the secure car call log, these phantom calls do not register as being entered. I can sit in the machine room and watch the calls latch on the screen as well as on the HC-CIO board.

I checked all triacs, zener diodes and resistors on the HC-CIO board, all checked fine. I replaced the board with a brand new board from MCE, no change. I have removed and reseated all ribbon cables. I have a new HP-CIO board and ribbon cables on order.

Any other ideas?

Nm, is this a serial data lift? Is the HC-CIO the electrical isolation for the lift computer, or just the button module? My thinking is, if it isn't serial data I would try to swap the individual floor level trailers to the these floors to see if the fault moves to another level. If it is serial data, then it should use this for communication from the car control pcb(car top isn't it?) to the controller. Maybe that cable is getting noise or induced voltages or maybe the car control pcb is faulty. The fact that you have already changed the HC-CIO pcb, tends to think this isn't the fault. From what I remember the buttons aren't individually coded so have you tried changing the button modules or wiring in case this makes a difference? Anyway food for thought.

check your travel cord,an car station something is taking those calls to ground.

Is the car sitting still or moving when these calls latch? If the car is moving, which direction? If moving, does it latch when the car passes at the same point in the shaft?

Disconnect you position indicator wires for 4 and 5. See if that stops the phantom latching?

Switching wires on the board as well as unplugging the wires on the board is a good idea to be 100% sure that the issue is in the controller, wished I'd thought of it sooner. There is no pattern to the calls latching; the car could be idle, running up or down, top or bottom of the hoistway, with or without passengers etc. The reason I didn't go after the traveler yet is because even if the call signal goes to ground, three other buttons (in the correct sequence) would also have to ground.

By the way, I did call MCE and they were not full of ideas. They suggested checking for power supply issues (mainline to mainline) and looking for sources of induced voltage.

is it a single car, or in a group? if it is in a group, check to see if the communication LED on the swing panel for the car you are having trouble with is going out intermittently. If the led goes out, and the car is not communicating to the group, it will start going into a wild car type mode, where it will automatically register car calls and stop at those floors, and continue until the communication is re-established. worth a shot, i had a bad ribbon cable from the comm port board to the swing panel in the car, and the group comm led was out, it would just register random calls until i replaced the cable. just another idea. good luck

Is the call dropping when it gets there? or staying on? I have had a lot of issues on a new job with induced voltage. I have also learned to ask for Chris at MCE he is a very sharp guy, even If you have to leave him a message to have him call you back he is worth the wait. I have been mislead by others only to buy more parts it seems.

Have you tried wiring the car calls (4C, 5C) into the hall calls (4U, 5D) instead to see if the phantom calls still register?

A fellow mechanic also suggested looking for loss of communication, I did not see this occur.

Yes, the call drops. I did speak with Chris, he also suggested looking for induced voltage.

Should have a board tomorrow, so I will be going back to install the board and measure ribbon cables. I will give this a try.

ive had this happen on older turnbull and dover tractions. I had a bad power supply that was feeding the floor cards and it would drop just low enough to latch the call then stabilize. just another thought.

New HC-PIO board didn't do the trick. Removed the traveler wires from the input terminals where my phantom calls are latching, calls still latch.

Got a good guy (James) from MCE technical support. After lots of poking around he suggested the same things that were mentioned here and by others I work with.

He had me check Bus 2 from controller to controller (ST2A to ST2B) in the group controller, they should read 60VAC or less between each other. I read 120VAC between the two, this indicates that the cars are out of phase with each other. This issue normally shows itself upon start up, apparently it can cause all kinds of oddball problems such as mine.

I ran out of time and didn't have the correct ring terminals with me today. When I go back Monday, I'll have to swap two legs feeding my main transformer until the cars read in phase. If this doesn't fix my issue, tech support suggested changing the MCCGDP board. I am going to order the board anyway.

Good find, phasing of each car in the group was somthing that used to be done regularly, I still did that when I was in the field. I advise the younger guys to do this when they Mod, even though most of the installation documents we see now don't address this anymore.

Hey e311, id like to understand this more. Is this only for the bus supply or for all supplies? I take it the group controller has an output for the bus to each individual lift controller. This would come from the original power supply to the group and then the pcb's split it where it is all needed. So are we just talking about +/- being reversed and thus 180 degree out of phase? What was your process for getting the cars in phase with each other, as I cant say I have ever had to worry about this?

Hopefully the 3 phase feeds for each controller come off of the same switch gear. Each controller will use a main transformer supplied buy its individual 3 phase disconnect. This controller transformer will typically take two legs of the 3 phase and convert that voltage to 120VAC for controller voltage. If one elevator is utilizing say, phase #1 and phase #2 of the 3 phase power supply, and the next elevator is utilizing phase #2 and phase #3 for its power supply, you now have a difference of potential between these two controllers. When these two controllers are connected via group connections, you have a doubling of voltage between the shared circuits.

Ah thanks mate now I understand what you meant. This is why I haven't come across this as, most of the time if you use a 3 phase step down transformer(ie you use the 3 legs), which we always do, you don't have these issues. Cheers mate.

NewMech,

Thanks for keeping us posted. Please let us know how you make out on Monday...

Go Nationals!

So...........stopped by the shop and ordered the MCCGDP board as well as replacement ribbon cables, then headed to the job.

Before I changed any wires around I double checked my voltage controller to controller, the cars are in phase without having moved any wires. Don't know what the hell is going on.

Boards should be here tomorrow, before changing them out I'll check the controllers for correct phasing. Around the lunch table we came to the conclusion that there is a building power problem.

I'd disable the security and see if it still happens. It's odd that it only happens on the secured floors.

I haven't been back to the job, the shop has been slow ordering parts. Will post any findings when I return.

I kept referring to the board as an "MCC-GDP", it is actually called an "MCC-CGP" board. Either way, I changed the board yesterday and it didn't fix my issue. Controller power supplies measure in phase, I am out of ideas.

What is the MCC_CGP pcb? Is this the main pcb for the SLC(single lift computer). From what you have said, you have isolated the calls from the from the shaft so to me it can only be the SLC that is generating these calls. Have you disconnected the complete chain that goes down to the car calls? If not I would completely disconnect any and all down chain equipment (for the calls) so as really know where this is coming from, and see if these calls come in again. Then you can go back to the manufacturer with more info on the how it all works software/hardware etc.

I think its fixed.

I changed all ribbon cables with no effect on my problem, so I called MCE again. The troubleshooter had me check for a loss of communication on the swing panel of the group controller, turns out I was in fact losing communication.

MCE has two different types of "receiver-driver" chips on their communication (RS?) boards. Looks like the problem car and the dispatcher have the weak version of this chip and my nice elevator has the good version of this chip.

To eliminate communication loss, there are two jumpers on each communication board; they take a resistor to ground at the end of the communication link. I moved the jumpers on both cars, my communication is now good and my problem disappeared.

So, I ordered new chips for both cars (a few bucks a piece).