LGB 55070 Feedback module problem

G

Gorsebank

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Hi

I am very close to running the Lighthouse, Gorsebank and Bride Railway under computer control but have hit a very strange problem with 2 different 55070 feedback modules.

When either 55070 is connected to the Massoth Dimax 600A transducer module without any wiring connected to the 55070 everything else works fine, points operate via decoders etc.

With Two track contacts connected to terminals 129a and 129b of either 55070 module the contacts are read by my PCs running stelwerk easy. As soon as I connect the common connection of a second pair of contacts to the common terminal between terminals 130a and 130b or any other common on the module all point control is lost and no contacts are read.

If I remove the original track contacts from terminals 129a and b and put them, or any other contacts, into any other pair of terminals they work but as soon as I touch a common wire from any other pair of contacts onto any other common terminal the problem returns.

I have tried connecting a coil of single core cable to a common, this does not cause an issue.

The wiring between track contacts and 55070 modules is brand new, run under the soil in the garden and no voltage, as you expect, is measured across the track contact wires

This has got me baffled, any help would be much appreciated.

Ian
 
I assume you are using a Massoth central station since you are using the 600A transducer module. If so, you should be able to program the LGB 55070 feedback modules to be used directly with the Massoth central station and avoid the use of the transducer for these components. I don't know if this will resolve your issue, but could be a way of testing if the transducer is causing an issue.
 
Not used these, but had a quick look at the manuals..
Are you *sure* you do not have a common wire connected to a switch contact somewhere?
Are you using a Massoth module as a master? - If so, have you left a programming wire connected?

Could this be a faulty track contact?
Do you have multiple power districts?
Could you have a track contact reversed?

Some of the above may not apply, or a 'dumb-ass' questions as I have not used these modules.. It sounds like a basic wiring error, or a 'leaky' module perhaps??
 
Hi Loco

Yes I am using a Massoth central station, I was not aware that the feedback modules could be re programmed to avoid using the transducer, this would help eliminate a potential problem.

Would you know were I could find the information to do this ?

Having said that I have had the system fully working on the bench prior to installing in the garden and everything including the transducer worked fine ?

I will bring in the feedback module tonight and re try a bench test, can the lead from the transducer to the feedback module be to long, mine are around 8m ?

Regards

Ian
 
Hello Ian.

The information I gave you was wrong! In order to use the LGB 55070 without the 600 A transducer you would need to use a Massoth feedback module as master, and then connect the LGB 55070 as slave(s). So if you only have LGB 55070 modules you will have to use the 600 A transducer, sorry about the confusion.
 
Hi Loco

Not a problem

After spending more time on the problem tonight I think I have found the problem but it is something I don't understand.

By substitution and bench testing everything works perfectly until I connect any of the buried twin cables from the track contacts to the feedback module. Even with the track contacts disconnected from the ends of the twin core cables. I only have to connect the common or switch wire ( not even both ) from any of the twin cables and the system locks up. As soon as removed everything goes back to normal.

Any other suggestions would be appreciated.

It will try wiring a number of track contacts to the module with new cable on the surface as a trial, it is strange as I am using the same cable to all my EPL drives and they are all working fine.

Regards

Ian
 
Loco said:
I assume you are using a Massoth central station since you are using the 600A transducer module. If so, you should be able to program the LGB 55070 feedback modules to be used directly with the Massoth central station and avoid the use of the transducer for these components. I don't know if this will resolve your issue, but could be a way of testing if the transducer is causing an issue.
Click to expand...

I would like to know how you reprogram the 55070 module to work with a DiMAX bus as I am not aware that it is possible?
 
Gorsebank said:
Hi Loco

Not a problem

After spending more time on the problem tonight I think I have found the problem but it is something I don't understand.

By substitution and bench testing everything works perfectly until I connect any of the buried twin cables from the track contacts to the feedback module. Even with the track contacts disconnected from the ends of the twin core cables. I only have to connect the common or switch wire ( not even both ) from any of the twin cables and the system locks up. As soon as removed everything goes back to normal.

Any other suggestions would be appreciated.

It will try wiring a number of track contacts to the module with new cable on the surface as a trial, it is strange as I am using the same cable to all my EPL drives and they are all working fine.

Regards

Ian
Click to expand...

Perhaps you are getting an inadvertent short to ground (as they are buried) and the modules are not liking it one bit causing the bus to fail. I would run a temporary cable and retest, if all goes well, replace the original cable.
 
As Mark says..
If bench testing is OK. Then you either have a faulty module in the garden you are connecting to, or (much more likely) a cable fault. - Note I said cable, and not wiring, though you could have a your wires crossed somewhere.

Standard fault-finding of a 'system..
Split it in half, and test.. If fault in first half, split that down.. If not, fault in second half.. Connect that, and split it.. Keep going until you find the faulty component..

Else, if you think the first cable out is the problem, run a cable to replace this first..
Break the fault down. Work it through, and you will get there..
 
Problem found.

Standard LGB cables are not long enough to reach from the transponder to the feedback module, so I made up my own.

The cable I could obtain had the correct number of cores and fitted the plugs perfectly. But was of a smaller cross sectional area.

The feedback unit works when the track contacts are within a short distance of the feedback module but as soon as the length increases to over a meter the problems occur.

I made up a new lead out of two lengths of 1.00 mm twin and earth cable which immediately cured the problem.

I still don't understand how it caused the problem with only the common connected but it did, electronics ha.

Is anyone aware of a supplier of longer LGB comparable cables or as anyone made their own and if so we're did you obtain your cable ?

Thanks for all the suggestions, it helped.

Regards

Ian
 
I am a little confused....

Which cables do you want to replace....

---the Bus cable (between the feedback module and the transducer)

or

---the sensor cables (between the feedback module and the reed switches)

?


If you require a bus cable, I can make them to order see http://gardenrailoutlet.co.uk/dimaxmts-bus-cable-2
 
Hi Mark

It is the bus cable between the Massoth transducer and Lgb feedback module.

I will need three of these, and we'll get outside later and measure the lengths, it is blowing a gale on the Isle of Man at the moment.

How quickly could you make and despatch these as I am on holiday this week due to the TT and I would like to get them installed whilst I have chance to do it.

Regards

Ian
 
If the cables are (much) longer than normal, it is possible you may still have a problem?? - That supposes there is not a problem with the cables you made up..
 
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