DCC issue with Heljan Turntable

Good detective work, Brian. I tried to reproduce your results by changing my TT's base address to 16, creating a couple of double slips in TC and creating a macro to switch them repeatedly in quick succession by pressing a button. I wasn't able to reproduce your findings, however since you have been able to solve the problem by introducing the 2000ms delay, I think that it is fair to say that you are correct and that the decoder is too slow to react to multiple commands.

So, the two known issues now have workarounds and hopefully others will now be able to avoid these pitfalls (pun intended!)

I've created this table, maybe it will be of some use to others, at least to demonstrate the principle of the +256 bug.

 

Out of interest, has anyone tried using iTrain instead of Traincontroller with this turntable? The reason that I ask is that for TC users, the Heljan TT isn't really supported by the software, unlike Marklin, Fleischmann and Noch, and simply comes under the generic heading. I have downloaded iTrain and see that the Heljan TT is listed in the TT options. I did a quick and dirty setup of the turntable in iTrain and it seemed to work ok but without setting up the rest of my layout, I can't really tell if the software handles the TT any better than TC. I've had a look on the iTrain forum but there aren't many references to the Heljan TT and what is there doesn't give much information. If there are any iTrain users who have the Heljan TT, it would be interesting to get their feedback.

Finally, in post #34, Martin wrote that he had contacted Heljan about the decoder issues, I too have emailed them but as yet have had no reply. Has anyone else been in contact with Heljan and has anyone had a response yet?

George

 

Hi Brian, your response from Heljan is disappointing but not unexpected. In their defence, they have no control over their customer's choice of equipment or their standard of wiring. It's an easy thing to blame "noise on the bus" and in fairness they could be right. We can complain that no other decoders are affected but that might just mean that their decoder is just a bit more sensitive than other manufacturers or than those home brew arduinos that some of us are fond of using. That would certainly explain why some of the randomness of the faults cannot be reproduced from one system to another. However, and this is the most important thing, the +256 bug is able to be reproduced and indeed, they should be able to reproduce it themselves. This is the absolute proof that there is a design fault in their decoder and they should do something about it. Interestingly, I used a tutorial on another forum to get my turntable working with TC, this dates back to 2012 and there are a lot of forum posts but never a mention of any addressing problems. As you will be aware, there are two unmarked buttons on the blue box which on earlier versions controlled the turntable speed. Somewhere along the line, there has been a design change and as you will already know, the instructions don't match reality when setting up tracks. Out of the box, track 1 is assigned 225 red/curve/thrown and track 2 is assigned 225 green/straight/closed. According to the instructions, when more tracks are added, track 3 will be assigned 226 red/curve/thrown and track 4 will be 226 green/straight/closed. In practise, as soon as track 3 is programmed it becomes 227, track 2 becomes 226 and like track 1 which remains 225, all are activated with a single press of the relevant number. It matters not whether the command is throw or close. That makes life simpler, one track = one number but it does point to a design change in the decoder somewhere along the way. Hopefully, Heljan will give this matter some attention but if not, hopefully the workarounds that you have identified will be good enough to keep us all working correctly.

Thanks again

George

 

I have now had a response from Heljan regarding the turntable. Make of it what you will but it reads to me that they are saying, we've sold loads of these and you are only the second person to complain. Anyway, the respondents contact details are here should anyone else wish to register a complaint.

George