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Motor/Chip Polarity





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#1 WIMorrison

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Posted 11 July 2018 - 19:16

I have a couple of locos which jerk backwards rather than forwards when on the programming track and occasionally my control programme get confused and 'forgets' the correct direction for these locos.

 

I am wondering if these locos have the motor connection the wrong way round as I would expect the motor to jerk forwards not backwards, but it may mean nothing at all - any thoughts?

 

Thanks

 

Iain

 





#2 Phil S

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Posted 12 July 2018 - 08:30

The direction in which the loco moves for the 'motor acknowledgement' pulse will be decoder-designer-dependent  -  and quite often I find this is 'backwards' - but then it also depends on whether you have a Hornby Select - whose manual certainly originally stated that the < arrow was forwards because that is the way trains run through a platform!

(I believe in later software, the .> button can be made forward on these controllers)   LGB (G Scale) adopted the opposite convention to other gauges for forward:

 

'Normally' it is the Right Rail Positive=Forward , but not with analogue LGB - So Bachmann add a switch for 'direction' to their large scale locos 8-)   ... and there can be a 'mix' in LGB digital users between those using the LGB handsets *MTS' - {{early Lenz-nmra-dcc)) and 14 speed steps, and others using later controllers )'nmra dcc/ Massoth handsets with 28/128 speed steps, or now the Marklin CS3+, who may have  adotped the dcc standard as with other models.

 

AS TO your 'controller' apparently forgetting the direction of these locos - UNLESS you have used CV29 to INVERT the direction - and then performed a decoder reset- i am puzzled - although with diesels/electrics it can be hard to remember or spot the 'No1 end' ... and which way do you call forward with a Class 8 or Class 20 ????  (and that's before you start running class20's in pairs, back to back - or is that front to front ???



#3 WIMorrison

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Posted 12 July 2018 - 08:37

I didn’t say controller, I said control programme ;)

My controller works perfectly.

#4 Phil S

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Posted 12 July 2018 - 10:33

The 'programme' IS the controller in this case  ... via the hardware controller...   the same answer still appies - unless you have reset the locos after a CV29 inversion to corredct diversion, .. no explanation

 

(With a Z21, Multimaus or MCP,  left and right may be reversed in respect to Lenz's interpretation = but that is a different issue, as is the accessory address starting at module 0 or 1.   I think only the Hornby controllers offer the choice of which direction is forward < or > 8-) )

Again, computer software can offer a reversal of left/right  .... AND it is possible, especially in connection with CONSISTS - that the software program is overiding the normal direction of the loco   --- but you havn't identified which software that is, so one cannot help..


Edited by Phil S, 12 July 2018 - 10:39 .


#5 WIMorrison

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Posted 12 July 2018 - 12:06

Unfortunately phil you are very much over-complicating things when there isn't a need to as all the complications are external to the question I ask.

 

My software occasionally loses direction polairty, which is probably due to mis-interpretation of Railcom, but it most definitely has nothing to do with CV29, Hornby, Lenz, Marlin, Massoth or any other DCC controller manufacturer.

 

Now back to the question which was does the direction that that loco jerk when on a programming track suggest that a chip has been wired 'the wrong way round'



#6 Phil S

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Posted 12 July 2018 - 12:14

I simply repeat the first line of my original answer

 

The direction in which the loco moves for the 'motor acknowledgement' pulse will be decoder-designer-dependent

 

There is no 'rule' which says which way any decoder will 'pulse' the motor - it is designer dependent.

 

I then suggested other options, but won't bother again.  answers are always provided not just for the original poster, but others reading the same subject heading.


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#7 Crosland

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Posted 12 July 2018 - 13:25

Now back to the question which was does the direction that that loco jerk when on a programming track suggest that a chip has been wired 'the wrong way round'

 

No, unless you have a definitive statement from the decoder manufacturer as to which direction the motor is pulsed during programming.

 

You could design a decoder to alternate, to prevent the loco creeping off the end of the programming track.



#8 WIMorrison

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Posted 12 July 2018 - 14:41

Like the alternate pulse idea :) I considered a circular track for programming but as I only really use it for speed curves it seemed a tad excessive., it was writing one the other day that made me think about this as one of the 2 locos i was profiling jerked backawars and the other forwards. I reaely use the track as 95% of programming is done using POM which with Railcom is very acheiveable, it just isn't that suitabale for doing speed curves using POM, especially not with DecoderPro as it is quite slow when using it on POM.



#9 markw

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Posted 12 July 2018 - 21:55

No, unless you have a definitive statement from the decoder manufacturer as to which direction the motor is pulsed during programming.
 
You could design a decoder to alternate, to prevent the loco creeping off the end of the programming track.

ZIMO did, it has been the default action for several years, but you can overide this and choose which direction it drives.
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#10 RAFHAAA96

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Posted 13 July 2018 - 07:25

Maybe a question you could ask of iTrain, telling them which controller you use with their software.
Rob

#11 WIMorrison

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Posted 13 July 2018 - 08:30

Fear not, that question has been asked ;)



#12 RAFHAAA96

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Posted 13 July 2018 - 18:44

In the iTrain English manual download from here http://berros.eu/dow...in 4 manual.pdf

page 42, Options tab there is a track polarity box which the associated text says ...

Digital locomotive with RailCom® decoder - to correct the direction when a RailCom® detector always shows the wrong direction only for this locomotive.

Maybe that will help.
Rob

#13 WIMorrison

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Posted 13 July 2018 - 20:25

Unfortunately this version of the manual is a bit behind where the actual product is ;)

 

When using Railcom and feeding the direction into iTrain you set the polarity which you refer to as 'unknown' and iTrain then accepts the polarity provided by Railcom. This is generally accurate but occasionaly it the loco and iTrain get out of sync and in this case I noticed that this loco (which is one of the main culprints) stepped backwards when in the track hence the question.

 

Do you use iTrain?



#14 RAFHAAA96

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Posted 14 July 2018 - 08:53

 
Do you use iTrain?


No - I run Railmaster and Rocrail and occasionally UK Rail Director. I couldn’t get on with JMRI for some reason.
Rob

#15 WIMorrison

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Posted 14 July 2018 - 13:41

i understand yur view on JMRI, seemed way to awkward for me - I also looked at RocRail and almost ended up there but didnt - and am now happy that i settled on the right product (for me at least :)