Home Forums General Discussion Technical Questions Otis Gen2 losing RSL

I have a 3 car group. Cars 2 & 3 run completely fine, but car 1 is doing all sorts of crazy stuff. It'll work fine for short while (about 5 minutes max), but then my earthquake relay, my fire service relay (PHI) and my switch over relay on my SOM will all pick and drop in no particular order or pattern. Sometimes it will hold the earthquake relay and shutdown on EQO, sometimes it'll shut down on EFOand pick the PHI contactor, and sometimes it'll shutdown on NAV when my SOM relay drops - it's all random. I can sometimes do a 151 and it'll return to service, but then it'll start doing the relay nonsense not long after. I have my 30v all throughout my RSL when this happens. My GL1 LED on my RCB2 board will go out (indicating I lost my RSL) when my SOM drops, which makes sense. I also notice when it shuts down the frequency across my group communication stops fluctuating - I noticed it typically bounces between 3 sets of numbers when running normally, but I can't recall what the Hz are. I've swapped the RCB, SOM, and my C1RS board for fire service with car two to see if i can move the problem, but it did nothing. I've removed RS boards to try and eliminate the problem, but obviously my unit just shuts down on whatever board i remove (ie fire service for C1RS). I'm questioning whether my termination resistor for group network is bad, or CPU is bad, or possibly my MLB, maybe even my chips. To be honest I'm completely lost on what to try next.
I'm headed back there first thing in the morning, but I'm shooting in the dark at this point. Any and all suggestions are immensely appreciated.
Work safe

When I run into RSL issues I usually start by routining all the RSL connections. It’s time consuming but make sure all the IDC connections are in good order. Verify line terminators are set properly. The good thing is yours sounds like it happens often. I would start by disconnecting your car RSL or a majority of the car RSL boards (buttons, PI, etc.) and see if it clears the issue.

I disconnected all my car boards and all appear to be in working condition. Just for fun, i replaced my batram chips, but that didn't do anything. So it looks like I'm going through the hoistway ducts next... yay!

A few things to check. If you have a meter that will read hertz check that your RSL is running about 1200-1240hz AC. Can you read the end of line terminating resistors on each link, car, hall & group? Do you have any AC noise on the 30 VDC?

So I haven't checked for AC noise yet, but I read Hz on both my God cars and the one that's acting up. Not one of them read anywhere near 1200Hz. The closest I get is 98 or something, but it bounces around so Ican never get a good read. I can't seem to locate the terminating resistor in the shaft, but to be fair, i haven't fully gone through car 3s shaft yet. So I tried disconnecting every RS board i can find in the controller and the car. I then read to ohms on each network. To my understanding, I should have on rcbs p5 plug somewhere around 100ohms...ish - that's terminal 2-3, 4-5, & 7-8. I plugged them in one at a time and read ohms and I happen to be good on every board. except i question 7-8 since I'm only getting about 60 ohms. However, when I power up, the problem returns. When it does, I pull my p5 connector off, ohm through each network, and find across 7-8 I have 170,000 ohms. Which makes me think I'm having car network issues. Could it be one of my buffer boards? I'm not sure how to test one of those. I'm also getting a 1709 fault - which is something about a car stop switch override on fire service I think. Again, making me think something with the car
I'm going back Monday. I'll start with the ac noise. I'm at the point of just throwing boards at it. Hell I've already replaced the software 😅

I think you see that kind of frequency when you read across the channel, read from blue to ground and you should see much closer to 1200hz.

Ahhh, that makes more sense. Duly noted

I'm back today.
I checked blue to ground on each network:

Group serial(P5) = bounce around 50Hz to 73Hz. I noticed sometimes the Hz will bounce up to around 600. After a while it goes to 0 and stays there

Hall Serial(P3) = stays consistently at 554Hz

Car Serial(P8) = 1200Hz

I'm trying to isolate the risers but so far nothing is consistent. I read AC ln the rsl and i got 0.7V on both my group and hall rsl. I had nothing on my car

You should be seeing 1220-1240hz. DL1 to DL2, meter set to DC Hz.

Can someone please explain the whole frequency in Hz thing as a way of determining the RSL is "good" ? What is that based on?

Instead of voltage through the wires, you have pulses, which is read with frequency. All data is read and outputs are updated 10 times per second. Its a talk then listen aspect - talk cycle updates tth he outputs and the listen cycle reads the inputs.

That being said, my Hz are no where near 1200 on my group and hall station. Even after removing both risers I have around 50-90Hz. That's after completely removing the wires completely off the controller.

Reading RSL frequency accurately depends on the meter that you use. Healthy RSL frequency toggles between 1226 and 1234hz AC.

Fluke 87V auto ranges correctly and will give you an accurate reading immediately.

Fluke 177 or 179 does not. These meters require manually ranging to 600mv AC and then selecting the frequency function.

I have seen problems at 1220hz and at 1250hz. 1226-1234 is fairly critical.

Also, you should be metering between the two communication wires, not to ground.

So I have a fluke 177. I did the manual 600mv AC Hz and read it as toggling between 1224 and 1232. When it starts losing it's mind again I read roughly 971Hz steady. I checked my other two cars and got the toggling of 1224-1232 even while car 1 freaks out. So where I'm at now is, I know I'm losing my RSL, but why? I've replaced and swapped every board except the drive, I've checked all my wiring, all my remote stations, and completely removed my group communication and the shaft, but nothing has changed. Could it be software related?

Here's a video of the excitement

https://drive.google.com/file/d/1zs0HTu5-LuVsrMorrtdWAP_Be1HuRBlF/view?usp=drivesdk

WOW, that is unusual for sure! Just wondering if you checked the AC noise on the 30V part of the RSL comm link? Can you read the end of line resistor on the car link? It's there to eliminate noise and interference. It sounds like your car link is possibly what's causing your chaos. Have you checked the traveling cable? Are you able to run the car at all on controller inspection or cartop? Sorry if this was already asked but I would step back to basic operations at this point to eliminate or to prove out any basic controller functions.

To everyone involved thank you so much for all the assistance. That being said I found the issue.
I ended up isolating the car and hall away from the control. I noticed as soon as I plugged in my car data wires (terminal strip 145 & 146) that's when it started freaking out. I then removed all rs boards and plugged in one at a time. However, this entire time I was forgetting one board...
The car directional lantern...
I popped the cover off and low and behold, my lantern board was missing. That's because it was never snapped into is base properly and it fell down into the back of the COP. the plug on the board was every so often shorting to the inside of the COP. Its back in place and the unit has been running non stop with no issues. Yes, I feel dumb for forgetting such a simple check of the DI. 😅

Awesome! I'm glad you got it resolved.