More Variable Voltage Issues with TIU / WIU

It looks to me, from the videos, that there's a latency or buffering issue that could be related to the WiFi that you're using.

I'd suggest that you attempt to replicate the issue using the WIU in MTH mode. That will rule out everything except the DCS equipment and your smart device.

What are you using for a smart device?

Thanks Barry. I have tried both Home and MTH networks. I currently have the WIU hardwired with an Ethernet cable. I have tried three different routers. As a last resort, I have purchased a Dual Band WiFI router which I will configure as a WAP, and wire it directly into the WIU. My hope is that if I can possibly eliminate interference, if it exists, on the 5GHz band. I am using an iPad and iPhone 6.

Greg,.

If the problem persists when using the MTH mode for the WIU, the problem is definitely not the home network. You're wasting your time trying to solve it with a different router. The problem can only be one of the following:

1. The DCS App has a bug.
2. The smart device that you're using has an issue, perhaps in its WiFi functionality.
3. The WIU has a problem.
4. The TIU has a problem.
5. The cable connecting the TIU and the WIU has a problem.
6. The layout has a problem.

In order to zero in on where exactly is the problem, I'd proceed as follows. After each step, test for the problem. When it goes away, you've found the culprit. Do all of the following with the WIU in MTH mode.

• Disconnect the TIU's variable Channel output from the layout and substitute a 3' or so test track.
• Swap out the cable between the TIU and the WIU.
• Use the other TIU variable channel.
• Use a different TIU (if available).
• Use a different smart device (if available).
• Use a different WIU (if available).
• Use a different smart device (if available).

After each step, you'll be narrowing down the list of possible culprits.

Thanks Barry. I have tried a new dual band 5 GHz router, hard wired directly to the WIU, to eliminate Wi-Fi interference as the issue. I have tried all new cables. I have tried an isolated test track. Tried other variable channel. Tried 3 different smart devices, and 3 different power sources, vintage and modern. Tried powering from AUX instead of Fixed 1. Tried re-flashing the V1.1 firmware to the WIU. Reset WIU. Tried wired and wireless, home and MTH networks. The only thing I can't do is figure out whether the WIU or TIU is at fault by swapping out extra equipment I don't have. Buying another TIU or WIU might be a good option, but it seems like we are just throwing good money after bad. 

Meanwhile, the violent voltage swings continue, unfortunately. At least I have learned to keep engines off the track while testing things.  Sometimes the voltage will surge all the way up to 20V with no warning, at odd times like when I am lowering voltage from 12 to 10 volts. There is no pattern. Just random disconnects and sudden voltage surges and drops that have cost me only a few more light bulbs (no more engine fatalities thankfully)

I think I need to abandon the whole DCS system and go back to Legacy. I have wasted about 50 hours trying to get the TIU/WIU combo to play nicely, to no avail. If I can't tweak this system to work correctly as an engineer, I wonder who could? Right now,  I have about 120 engines, of which 117 are Lionel, 2 are Williams, and only 1 is MTH. So, no big loss. I recently purchased a new MTH Via Rail F40PH, as my first venture into the world of MTH after never touching the stuff for the last 30 years. This could have gone either way, but this experiment went in a very bad direction and has left me with a very sour taste about MTH products as a first impression.

Thanks again for all your help. Just wish that I could have received the same positive experience with MTH that others have enjoyed.

Greg,

Does it do this when using the DCS Remote?

I do not have a remote. There is one additional behavior I observed, which may be a clue regarding the source of the problem. You may recall that the voltage adjustment becomes unresponsive, and then suddenly a cascade of voltage up/down commands stream through after about a 10 second pause. When this occurs, I noticed that the lights on the WIU flicker indicating data passing through, just as they would when I make a voltage adjustment when the unit is functioning correctly. So my question is this: Do the flickering lights indicate backed-up data suddenly being communicated from the iPhone to WIU, or does the flickering represent backed-up data being transferred from the WIU to the TIU? Is it possible that the app is at fault, delaying transmission of data to the WIU? Or is the WIU holding data?

Greg,

Do the flickering lights indicate backed-up data suddenly being communicated from the iPhone to WIU, or does the flickering represent backed-up data being transferred from the WIU to the TIU?

The following are opinions based on appearances, only.

Which LEDs are showing activity? If it's the WiFi LED, I'd say that it's the app sending to the WIU. If it's the TIU LED, I'd say that it's the WIU sending to the TIU.

If it's both together, then the delay sounds like it's in the app before it sends to the WIU.

Barry,

Both the LAN and TIU lights show activity after the delay. I agree with your logic that it may be the app causing the issue.

Greg,

Are you using an iOS or Android device?

GregR posted:

The only thing I can't do is figure out whether the WIU or TIU is at fault by swapping out extra equipment I don't have. Buying another TIU or WIU might be a good option, but it seems like we are just throwing good money after bad.

That's a pretty huge gap in trouble shooting!

Isn't there a hobby shop, club or someone local with DSC setup - take your stuff there and see if the problem follows you?

I'd rule those out before I start speculating about the app.

Barry Broskowitz posted:

Greg,

Are you using an iOS or Android device?

iOS

Roving Sign posted:

GregR posted:

The only thing I can't do is figure out whether the WIU or TIU is at fault by swapping out extra equipment I don't have. Buying another TIU or WIU might be a good option, but it seems like we are just throwing good money after bad.

That's a pretty huge gap in trouble shooting!

Isn't there a hobby shop, club or someone local with DSC setup - take your stuff there and see if the problem follows you?

I'd rule those out before I start speculating about the app.

You have good points. Unfortunately, I don't have immediate access to a substitute WIU or TIU. I seem to be living in an MTH black hole. I work at a local train store where I do all the O and S gauge repairs. Although our store has plenty of Lionel, it doesn't even sell MTH unless it is by special order. There are only a few customers who run MTH, and those guys are conventional only. In fact, among our Lionel customer base, I would say 95 percent of them only run their Legacy engines in conventional. Not too many folks here have sophisticated setups. Most people here are either really old, or really young, with simple, mostly seasonal layouts. For my part, I have very little experience with MTH, and repair mostly Lionel and Williams equipment - that's what comes in the door. Less than 5 percent of our repairs are MTH, so I don't have to deal with diagnosing these issues on an average day. In many ways, I'm kind of a guinea pig for testing out these MTH products, as our store owners and customers are eager to learn from my experiences before expanding themselves into this technology.

Greg,

I spent a few minutes and was able to replicate your findings using the iOS and Android versions of the app - and also using a DCS Remote! 

It appears that this is a "feature" of DCS in general, rather than a bug in the normal sense.  

It would appear be a latency issue as regards the TIU's variable channel circuitry's ability to adjust track power in a timely manner when multiple power adjustment commands are sent in a very short time period.

I never run my trains conventionally, however, I strongly suspect that the bad behavior that you're seeing is not something that would be an issue during a normal conventional operating session.

I am quite curious as to what scenario you would need to operate the layout in that manner. Its a weird issue but my thought was a latency issue as well as Barry but he beat me to the punch.

This latency issue doesn't occur just because I fired off a rapid series of up/down voltage commands and overwhelmed something. I don't normally operate trains like a 5-year old I just did that for illustrative purposes on my video, so that I could bug it out faster for people to see. In reality, every adjustment to voltage, even single adjustments, has the probability of randomly producing this effect. Sometimes it locks up as soon as I first increase the voltage. Other times, it may only occur after a minute or two of normal operation.

I just heard back from Jason Wenzel at MTH. As I suspected, he confirmed that this is a known issue with the software that is being addressed by the app developer. In the meantime, this error can be prevented (in most, but not all) cases by raising or lowering the slider very slowly, with slight pauses along the way. I have tried this and it works about 90 percent of the time. However, sometimes, the voltage will still lurch around even if the slider is handled slow and gentle. This is not an issue with the TIU or WIU. Hopefully, it will be corrected on the next app release.