Massoth reverse loop module causes 'pausing' at both sensor gaps

beavercreek

beavercreek

Travel, Art, Theatre, Music, Photography, Trains
Country flag
I have converted a point to point shuttle line to a dcc double reverse loop line, using two Massoth reverse loop modules (one at either end).
The modules are set to use the sensors (which are wired using the diodes provided) and also to have 'short circuit' mode as a back-up. The strange thing is that one module causes the loco to momentarily pause at both the sensor gaps.
This pausing seems to happen to a lesser or greater degree with any loco.
I have checked the wiring, the gaps, the rails leading to the gaps etc etc.

The module at the other loop end of the line is totally fine, no pausing at all with any loco.

Could a module possible have an internal defect which causes it to run 'slow' when detecting the 'presence' of a loco?

I will try swapping the modules over but leave the wiring in situ to see if anything is untoward there, but it does seem a little weird.
 
beavercreek said:
I have converted a point to point shuttle line to a dcc double reverse loop line, using two Massoth reverse loop modules (one at either end).
The modules are set to use the sensors (which are wired using the diodes provided) and also to have 'short circuit' mode as a back-up. The strange thing is that one module causes the loco to momentarily pause at both the sensor gaps.
Click to expand...

Mike - I think the answer is on page 7 of the module manual: "Operating multiple reverse loop modules at the same time requires the jumper to be set (short circuit recognition deactivated)". Presumably you are creating a momentary confusion in the relay of one unit by having the short circuit option set (the default factory setting). Change the internal jumper to sensor operation only - it's better for your locos and central station and, in my experience, 100% reliable.
 
Hi Peter
Yes that is a possibility but...
I was told by Mohammed (Massoth US) that to have the sensors set with the jumper also giving short circuit 'back-up' is perfectly fine as the short circuit will only happen if the sensors fail. This is also mentioned somewhere in the manual, I think.

Also, surely, if only one train is operating over the whole double reverse looped line. One module will not be able to 'see' the other module as it is 'tripped' by the loco, so cannot be confused by it, due to the insulating gaps and the fact that the modules only change the polarity inside their respective loop not outside it.

I could be wrong of course....
 
Are you using the diodes? Are they installed the correct way round? I know you have checked the wiring but...are you sure that the sensor track connections are correct? Maybe try swapping them over.
 
Hi Mark
Yes the diodes are the correct way around (I was very careful with that)
But I am going to swap the two modules over so will inspect the wiring doubly close just in case anything has gone amiss.
What makes me think that it is not the wiring is that the pausing was only happening initially on the 'entrance' sensor and not the 'exit' one but it now happens at both.
But it always pays to check once, twice and thrice
 
Sorry to resurect an old thread, but did beavercreek manage to resolve this problem?

I've just installed a new 8157001 Massoth Reverse loop module and it exhibited the identical symptoms to those described in beavercreek's posts.

I too was careful to check the wiring, direction of the diodes, continuity checks on the circuit etc.

I resolved the problem when I noticed an apparent discrepancy in the wiring diagram illustrations in the Massoth instruction booklet. If you wire as per photo shown as Illustration 2, and not as the wiring diagram shown in Illustration 4, it works perfectly.

Wired as Illustration 4 and it only works erratically and with the pause as per beavercreek's description (ie apparently short circuit mode only).

The difference appears to be in the polarity of the power output wires from the reverse loop module.

Anybody else notice this?
 
No replies?

I've now added a second Massoth 8157001 Reverse loop module and both work perfectly provided you match the wiring as per the photo shown as Illustration 2 of the user manual.

Can anyone resolve the confusion re short circuit protection jumper settings or using/occupying two loops simultaneously as per confusing description in the manual and alluded to in on of Beavercreek's replies? I left both my jumpers as per the default settings and tested that you can occupy both reverse loops with no problems. Has anybody else tested this?

Final question - has anybody installed 3 reverse loops on 1 layout?
 
The problem is that in short circuit mode all reverse loops on the layout switch over at the same time because they all detect the same short circuit. This means that it may not be possible to have two (or more) trains crossing a reverse loop boundary at the same time.

In the mode with detection sections crossing a boundary does not affect other reverse loops and so it is possible for trains to be crossing reverse loop boundaries at the same time.
 
Cliff George said:
The problem is that in short circuit mode all reverse loops on the layout switch over at the same time because they all detect the same short circuit. This means that it may not be possible to have two (or more) trains crossing a reverse loop boundary at the same time.

In the mode with detection sections crossing a boundary does not affect other reverse loops and so it is possible for trains to be crossing reverse loop boundaries at the same time.
Click to expand...
Of course, the probability of this happening is quite small.. (BUT, what happens if it does??)
The more reverse loops you have, the more risk of it occurring.
However, knowing the laws of Mr Murphy and Sod, then if will happen at some time! ??? ::)
 
Thanks for the replies.

Aren't the modules primarily designed not to operate in short circuit mode? Doesn't the short circuit detection only come into operation as some ill defined fall back system that works very poorly even with only one circuit in operation.

When used used with the supplied track sensors, and wired as per Illustration 2 , they operate seamlessly. Whereas short circuit mode usually trips the central station anyway, so in effect they don't really work in short circuit mode irrespective of how many you operate.

Like any short circuit, they will trip out the central station, power supply etc, assuming adequate protection, and since you can only trip out once per short circuit I don't really understand the multiple loops problem. It's a bit like arguing that the more trains and rolling stock you simultaneously operate the greater risk of a derailment and an associated short circuit.

Any views on the wiring problem?

PS I sometimes wonder if the multiple loops confusion (if indeed that is what it is) started out with the obvious suggestion of not running multiple loops from one module and somehow got lost in the meetings/translation ;).
 
I notice that LGB have finally released their version of the reverse loop module, 55085 with the following description:

"New reverse loop module for the new digital LGB system world. You can switch the reverse loop on your digital layout automatically and free of short circuits. You will protect your digital layout and the rolling stock in the process. One more advantage of the reverse loop module: Several reverse loops can be used simultaneously on the layout. Reverse loop modules in use up to now cause a short circuit when the train enters the reverse loop and force the polarity of the track to switch by causing a break in the voltage, example: 55080. This new MTS reverse loop module by comparison switches free of short circuits; and interruption of the voltage in the track is avoided. The overloading of the MTS central unit by the intentionally caused short circuit is thereby a thing of the past."

Looks very similar to the Massoth 8157001 at about the same price (ca £70). Has anybody tried it?
 
GNB said:
I notice that LGB have finally released their version of the reverse loop module, 55085 with the following description:

"New reverse loop module for the new digital LGB system world. You can switch the reverse loop on your digital layout automatically and free of short circuits. You will protect your digital layout and the rolling stock in the process. One more advantage of the reverse loop module: Several reverse loops can be used simultaneously on the layout. Reverse loop modules in use up to now cause a short circuit when the train enters the reverse loop and force the polarity of the track to switch by causing a break in the voltage, example: 55080. This new MTS reverse loop module by comparison switches free of short circuits; and interruption of the voltage in the track is avoided. The overloading of the MTS central unit by the intentionally caused short circuit is thereby a thing of the past."

Looks very similar to the Massoth 8157001 at about the same price (ca £70). Has anybody tried it?
Click to expand...
My guess is would be it is a re-badged Massoth unit??
Though Marklin do have the techies to come up with their own..
 
Well, I had forgotten that I started this thread nearly two years ago...

I have solved the 'pausing' problem with the Massoth reverse loop module.

My 'local' line had been a DC shuttle unit until I DCC-ed the layout. I decided to use two reverse loop modules, one at either end onf the converted shuttle line. I had obtained the reverse units some time back.

When the problem showed itself I then tried a replacement unit and it exhibited the same problem. I checked the wiring against the first diagram in the instructions but still the problem persisted.

I looked on t'interweb and found that another person had experienced the same thing when using the sensor mode.
There seemed to be an issue with the instruction photos/diagrams in the first edition of the instructions that come with the unit.
There are two pictures showing how to wire up the sensors to the track and they conflict on two of the contacts.
I reversed the contacts as shown in the second diagram and ...hey presto...everything worked as it should.

Apparently the instructions in the next iteration of the accompanying booklet have the photos/diagrams as exactly the same correct wiring.

Obviously I had originally wired one reverse loop module as per the second diagram and the other as per the first diagram so one worked fine while the other....didn't.

All is good now............and...oh yes....I have a copy of the amended instructions...just in case......
 
Thanks for that beavercreek we appear to have got there in the end.

The next person with the problem should now be able to find the solution when they use the search function. Which is where I started before hitting the buffers and finding my own solution. Good for my remaining little grey cell ;).

I found an additional point re the RLM in the Massoth catalogue, but surprisingly not in any of their other literature, it states that the module "supports a soft start function if the train stands on the isolated section", which appears to be the case.

Does anybody have any insight into how these modern Reverse Loop Modules and their sensors operate? If you listen to them and rest one in your hand during operation you can feel/hear what appears to be a solenoid operation (ie a soft clicking/movement when they are activated. If so, it must be very fast since their is no hesitation or light/sound interference when the locomotive crosses the sensor track.
 
You must log in or register to reply here.
Back
Top Bottom