Hornby R8238 reverse loop module

[pincher]

Sorry for the dense question, I have just got a reverse loop module and there is a switch on the front either select or elite ? I'm using a  elink . Will this work with elink and if so where do I put the switch ie on select or elite 

 

thanks in advance

dave 

[RB51]

I am not overly familiar with the E-link these days but far as I am aware Dave it is just to do with the power supply you are using. The E-link I believe ships with a 1amp PSU so you would use the Select option, if you are using this. If you have upgraded your supply to 4amp then use the Elite setting. R-

[Chrissaf]

Pincher,

Roger is 100% correct. A reverse loop module works by measuring short circuit current. When a trigger current is reached, the unit switches to remove the short circuit condition. The 'Select' switch position is used when the Hornby 1 amp power supply is used (regardless of the controller model) and the 'Elite' switch position is for use with the Hornby 4 amp power supply.

[96RAF]

Deleted as we are talking reverse loop not booster module....

the switch may have been better labelled 1A - 4A PSU.

Rob

[pincher]

Thank you all , it works a treat 

[Chrissaf]

Thanks for the update....

[pd91223]

Can you run 2 reverse loops from one RLM using Elink or Select with a 1 amp supply, even if 2 locos are crossing in to the two revers loop sections at the same time?

[Fishmanoz]

Hi pd, welcome to the forums. No you can't.  The requirement for isolated sections in reversing loops is that 2 or more trains cannot enter and/or leave at the same time.  If hat happens, the RLM will be desperately trying to switch the phase to match, then instantaneously have to switch it back over and over until all but one train at most is left in the section, and it cannot do that. 

[Chrissaf]

Fishy is totally correct PD, don't even think of trying it.

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This link will take you to Page 2 of an existing thread where multiple Reverse Loops are discussed. My post on page 3 of the same thread gives a little theory on how a RLM works.

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https://www.hornby.com/uk-en/forum/post/view/topic_id/15375/?p=2

[pd91223]

Thanks both. 

I've read the details from the link and believe I understand ok. If you look at the diagram below, I think the two red areas are the reverse loops in which case I'd need IRJs at each end and an RLM for each. The loops are relatively short (491mm & 867mm) so would this cause any extra issues, e.g. - theoretically probably rather than practically - what would happen if a combined unit, one loco at front and one at the rear crossed over in to the red zones?

All of this track, except for one element would be Hornby, initially controlled by a 1-amp Select, later by a 1-amp Elink. If Hornby has dis-continued R8238, what would be my best option for RLMs (subject to Forum rules, of course) or should I quickly buy 2 x R8238 from Hattons?

/media/tinymce_upload/8ab060e83ef12729dc1e8d76aae52289.jpg

[pd91223]

Thanks both.

I replied about an hour ago but this has not appeared here. Being new to the forum, can it take a while for replies to appear (moderation?) or could it have been because I tried to upload a diagram?

[pd91223]

I suspect that my upload must've caused the non-appearance, so let me try to continue without a diagram!

I've read the link and I think I understand ok.

What I'm trying to achieve will initially be controlled by a 1-amp Select, but later by a 1-amp Elink. I believe there are two short reverse loops (491mm & 867mm). I assume I'll need IRJs (insulated fishplates) at both ends of each reverse loop with an RLM for each loop with wires from the RLM connected to both the reverse loop and main track in each case. Are there any other issues to consider because of the shortness of the loops, e.g. - theoretically probably rather than practically - if there's a double-headed (consisted) unit with locos at the front and back, what happens as the locos enter/exit the reverse loops?

[96RAF]

To answer your last question, assume the polarity in the reverse loop matches the entering mainline as the double header runs into the loop.

As the first loco heads out of the reverse loop it trips the RLM sensor and the reverse loop polarity switches to match the exit mainline polarity and the trailing loco immediately sees the new polarity in the loop.

 

Your diagram upload was just badly timed as Adam the site admin is the only one who can approve pictures (during office hours) so it will be Tuesday due to the bank holiday before he sees it and allows it onto the forum.

Rob

[pd91223]

Thanks Rob

I'd still appreciate someone looking at my diagram next week to confirm that I've correctly identified my proposed RLs.

Meanwhile, in Chrissaf's Reverse Loops' post of 14/07/2016 he says "The only limitation is that you cannot have more than one train (loco plus rolling stock) entering OR leaving a RLM protected section at the same time. This is why a RLM protected section MUST be longer than the longest train." The max length of a train entering my 491mm RL is likely to be 480mm wheel to wheel and it's inconceivable (other than operator error!) that there would be more than one such train in that segment at any one time. However, the train length entering the 867mm RL could easily be in excess of 1m. Will I have a problem?

[Howbi]

If the train is longer than the loop surely the engine will hit the rearmost vehicles as well as the points changing before the last vehicle has passed.........HB

[Chrissaf]

Images are held back for checking (authorisation) by Hornby forum Admin (Adam). He and his team only work on the forum during office hours Mon to Fri (unlike the Community Mods who are on line all hours of the day). Being a BH weekend, your image (it will have been posted by the way) will probably appear sometime Tuesday / Wednesday next week.

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When you post an image, after clicking the 'save post' button, a message appears across the top the page informing you that the post has been posted but is held back for authorisation. You have to be 'eagle eyed' to spot this message and it is easily missed.

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If you become a prolific poster of images (i.e admin keep seeing your user name coming up for image authorisation), then admin may upgrade your account to one that supports 'instant image posting'.

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PS - the comment about the RLM section being longer than the longest TRAIN (loco including rolling stock) is 'best engineering practice' and should be adhered to if at all humanely possible. One forum member has reported seeing no issues with his particular RLM that was shorter than his train. But that does not mean to say that his RLM module and his DCC controller power supply was not still being stressed by constant switching as rolling stock wheels keep bridging the entry and exit IRJs sequentially. Remember it is not just the loco that triggers the RLM, metal wheels on passive rolling stock will trigger the RLM as well, as they are still allowing the RLM protected track section to be in electrical contact with the non protected section.

[westernwill]

If you cannot make the RLM part longer and still want to run long trains over it, then you can get over it by making sure the rolling stock has plastic wheels.

 

This will be fine as long as you are running a loco at the front and the rest is just rolling stock.

[Fishmanoz]

We will be able to advise further once we see your diagram but the chances are, despite the ifs and maybes above, this isn't going to work due to Rule 1 - isolated section to be longer than the longest train.  Try thinking about how you can achieve this by isolating differently. 

[westernwill]

Not a problem if you just have 1 loco at the front and the rest of the rolling stock has plastic wheels.

[Chrissaf]

Here is a better solution:

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/media/wysiwyg/Hornby/Forums/rlm.jpg

[Chrissaf]

In the meantime, whilst waiting for Adam to insert my image in my post above (requested by email). The image can be viewed using the URL link below. The link will time out eventually and this post removed once my image appears in the post above:

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https://btcloud.bt.com/web/app/share/invite/aecfvm7bWP

[pd91223]

Thanks, Chris

That makes sense and makes the length of each RL segment longer. So, I'm off to Hattons next!

[aj2010]

/media/wysiwyg/Hornby/Forums/rlm.jpg

[pd91223]

With my new found "knowledge", two R8238s and some insulating fishplates I thought I would try amending my existing layout with a reverse loop before I progressed to the layout I had posted here previously.

I've failed with a couple of attempts at isolating different segments, although I think the problem may be caused by an insulated crossover through the common section of the reverse loops. I've tried to upload a diagram of this layout but the upload dialogue always says "The file could not be written to disk"! Is this just a temporary problem? If it will be resolved early next week, then I won't try to describe the problems I'm having without the diagram.

PS I assume the red light on the R8238 means it's working ok!?

[Chrissaf]

"The file could not be written to disk"! Is this just a temporary problem?

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It is a site problem that is known about and has been reported as a fault to the website developers to fix. Is it temporary?. Well it has been like this for a couple of weeks now, and "how long will it will take to fix" is unknown.

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I have resorted to uploading important images to my ISP storage area and providing a link (like I did to your RLM question earlier). Adam (the site Administrator) finally uploaded my image for me, but he did report back to me that it was not straight forward and he had to find a 'workaround' to do it.