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| Programming CV's - DCC - Tutorials - Getting You Started. - Your Model Railway Club | ||||||||||
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Petermac Moderator 
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I finally managed to make some headway with the Bachmann Pannier tonight. Following your advice John, I reset everything to factory defaults then concentrated on CV2 alone. A value of 23 gave me a "start to move" on throttle 1 Following advice from everyone including here on YMR, DCC Concepts, Bromsgrove Models, Digitrax, Bacnmann and even the dog, I came up with the following values: CV 2 - 23 CV 3 - 8 CV 4 - 4 CV 5 - 50 CV 6 - 20 CV 54 - 27 CV 55 - 29 She creeps (excluding over the double slips  ) on trottles 1, 2 and 3 with very little difference between them, except she has a little more resiliance on 2 and 3. 4 and 5 produce a handy "yard speed". 6 gives quite a discernable leap but still not "over the top". 7 to 10 gives an acceptable "open country" working speed but much more, and she tends to run away. My track isn't long enough to see how fast she would go if given her head, so I'm not sure I've been able to limit the top speed. What I have done, is gain considerably more control over the lower end and that's what I wanted.Something is however, still evading me. How do I access and change the bit settings on CV29 ? The overall value of CV 29 is 6 which I'm told is about right but I'd like to look at the individual settings contained in that CV. There must be lots of them but I think the controller is only reading 2 of them ................ ____________________ 'Petermac |
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SRman Member 
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CV29 is additive. All those bits together add up to your value of 6. The programmer will not separate out the different bits in the readout. The first will have a value of, say, 2 and the second will have a value of 4, in your case. Each attribute within CV29 has its own unique values that together add up to whatever the final total is. Off the top of my head I can't remember exactly what values are to do what, except for that first bit with values of 0 or 1 which reverses the direction of travel. Other attributes would have values of 0 or 8, and 0 or 16, then for two or four-digit addressing, 0 or 32. I (personally - talking about my own DCC stuff here) would add 32 to that total value so I would be using a four-digit address and the value in my pannier would be 38. If I had wired it backwards then I would also have to add 1 to the value, in your case making it 7, in my case, 39, to reverse the direction of motion. ____________________ Jeff Lynn, Amateur layabout, Professional Lurker, Thread hijacker extraordinaire |
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John Dew Full Member 
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Well at least that is progress. Assuming for the moment that you are satisfied that the start voltage (2) is now acceptable I would start adjusting CV 6 , the mid point voltage. I am still confused about CV 6 on your chip.......according to the guide that Diablo posted (post#2), CV 6 isnt available and that was certainly the case with my cheap Bachmann decoders ...........however as you are able to adjust it set it about 75% of the value of CV 5 that will have the effect of making the speed curve concave ie more speed steps at the start. Its current setting is 40% of CV 5 (20/50) and this creates a convex curve ie less speed steps at the start which sounds like what you have now. Hopefully you will see a marked difference (75% isnt a magic figure I have used higher) If this works you could then try bringing CV 5 down (and of course CV 6 proportionately). Re reading the chip guide I am wondering if CV 53 (Back EMF) should be increased to get the speed down Not sure why you need to alter CV 29 but the Lenz manual does show you how to read the bits on CV 29 Hope this helps  ____________________ John Granby III Lenz DCC,RR&Co Gold V9 B1 Windows 10 |
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Petermac Moderator
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John Dew wrote:
I've now read the manual ..............................   ____________________ 'Petermac |
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Petermac Moderator
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Ok - I'm now pretty happy with things. I reset CV6 to 35, CV 54 to 40, CV 55 to 42 and CV 53 to 62. According to a Bachmann "generic" decoder spec, the range for these latter two CV's is 0 - 63 and, on that same sheet, there's no mention of CV 5 !!! Is it possible to programme a value, for it to read out and yet not alter the decoder ?  I have good (although, compared to both the Class 47 and the GP 40), not excellent very low speed control - still not a huge difference between Steps 1 and 3 but good enough. It certainly seems to have got rid of the "hesitation" on step 1. At step 5, she's beautiful. A gentle "trundle". I'm not sure what top speed should look like She is slower than she used to be and in fact, probably not far away from a "real" 60mph judging from the time she takes to cross the little bridge on the Maxmill Junction. As I said earlier, the laid track isn't long enough for her to attain full speed. From what I've seen, I can't imagine my wanting to operate at much more than step 10 anyway.......... My aim is to have a train / trains merrily running around on the lower level circuit - either express or slow goods - whilst I "operate" the slow running stuff on the Maxmill Town spur. I actually get a kick out of watching them creep along .............. When I decide how to operate the coupling, shunting will be great fun.When my back aches, I can simply sit and watch the lower level through the red haze of a Chateau Latour ..........(or, more likely up there, a Chateau Collapsible )____________________ 'Petermac |
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paul_l Full Member 
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Hi Peter Consider CV 29 as 8 separate switches which can either be off (0) or on (1) - binary bit. These switches or bits are added together to form an 8 bit word which in decimal gives a value between 0 and 255. A better description of each switch setting and a method of calculating the value can be found here http://www.2mm.org.uk/articles/cv29%20calculator.htm Paul ____________________ Victoria Road |
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Petermac Moderator
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I'm still struggling with fully understanding CV's.  DCC Concepts attempt to explain it all very well (http://www.dccconcepts.com/index_files/DCCdecoderfunctionsdesc.htm ) but, as with most things "technical", it seems to assume some existing knowledge and, to me at least, becomes confusing once I move away from the simple "Address" and "Start Volts" etc..................don't alter this without altering that and it will also effect something else etc.etc. . Some of the low number CV's seem to depend of how many speed steps the decoder supports. "Divide the speed steps by the track voltage .........." I checked the details for the Lenz Silver and it seems to support almost all possibilities - certainy 64 or 128. How do I know what is actually set at the factory ? It's all within CV29 but how can I read the individual "bits" in there ? I have just noticed that John (Dew) posted that it's in the Lenz manual ( ) which is in the attic .........I'll read it next time I'm "on high" ........Will programming CV29 change the individual bits in a pre-set order ? i.e. If I set it to say 7, will it know that I want (for example), bit 1 at 0, bit 2 at 1 and so on until it totals 7 or will it just mess them all up to make 7, whatever the order ? Also, the DCC Concepts article tells me CV 5 (Max speed), has a default of "0" which is the maximum setting for this CV. I though "OK, lets just limit the speed of the A3 slightly below the maximum" so I set it to 3. It crawled around at a snails pace but setting CV 5 to 258 let her rip. Does this CV use inverted values - i.e. "0" is Max but "1" is minimum and increasing the value lets the brakes off. Oh dear, sorry for all this .......... Is Ian Morton's DCC for Dummies book a good buy ? I obviously need to do some homework about it all .............____________________ 'Petermac |
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John Dew Full Member
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Petermac wrote: I'm still struggling with fully understanding CV's. What chips are you working with Peter............let me know and I can tell you the Factory defaults if you wish I never alter the Lenz speed steps the default is 28 ( and maybe 128) and they work fine for me The Lenz 100 manual shows you how to read and change CV 29.......I use it if I (or Hornby ) have reverse and Forward muddled.............I think your supposition is correct but I have always changed the individual bit......math not being my strong point0 is typically the default for CV 2, 5 and 6.............I dont think it inverts values as such and it doesnt affect braking it contols the supply of voltage to the motor....... but you are correct the higher the value the greater the effect.................CV 5 set at 3 would be very slooooow even for a pale green coloured loco ____________________ John Granby III Lenz DCC,RR&Co Gold V9 B1 Windows 10 |
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Petermac Moderator
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The decoder in question John, is the Lenz Silver in the A3. Whilst I haven't had time today (or tonight - Rotary) to have a "mess", even with CV 5 set at 258 (?), I don't get the speed it had on DC - not that I actually want that speed but I do need more than it's giving at present. It also seems to "hunt" a little. I'll check the con-rods to make sure there's nothing binding anywhere - it was a very tight fit getting the body off and it's possible I may have put a little pressure on the linkage somewhere. I'm really looking for a "CV's for Dummies" type tutorial so that I can start to understand what I'm doing and how these things work in relation to each other. Hence my question about Ian Morton's DCC book ........ Whilst it's great ot have all this experience at my fingertips, I'm sure in time, you'll all start wondering if I ever do anything for myself !!!! I realise your comment about pale green locos and their speed is sheer jealousy John so I won't comment further ...... ____________________ 'Petermac |
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John Dew Full Member
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Petermac wrote: The decoder in question John, is the Lenz Silver in the A3. ____________________ John Granby III Lenz DCC,RR&Co Gold V9 B1 Windows 10 |
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Geoff R Member
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As I mentioned in John's thread, I have fitted 12 Lenz decoders now. In every case I did not change ANY CVs other than CV1 for the address and every loco works just fine. I suggest, Peter, that with your A3 you reset the Silver to factory defaults for a start - program 33 into CV 8. Then program in the address you want into CV1, and try the loco again. The default Minimum speed is 0 (CV2), which means that zero power is fed to the motor at speed step 1 on the controller. The default Maximum speed is 255 (CV5), which means that the full voltage available is fed to the motor at speed step 28. The default Mid speed is 60 (CV6), which causes the decoder to set a smooth parabolic like curve of speed increase from no movement of the motor at speed step 1 on the controller through to maximum speed at speed step 28 on the controller. For me, this works absolutely fine. No need for any changes at all. If your loco is still not going as fast on DCC as it was on DC then there are other reasons, not the decoder setting. The first is perhaps the voltage being supplied to the motor. On DC it clearly depends on the controller you are using. If a basic Hornby or Bachmann controller, then it is a very "rough" DC and can be as high as 14 or 15volts if fed from a nominal 16v AC power supply. On DCC it again depends on the voltage being supplied by the controller, but there are some other things to consider. If your Lenz is being fed from a 14v AC transformer, then the DCC voltage may well be less than 14v peak to peak. When this reaches the Decoder, it goes through a full wave rectifier on the decoder board before being turned into another high frequency pulse of power which is fed into the motor. This pulse will have a voltage at least 1.5v below the DCC voltage, so you could end up with less volts on the loco motor when driven at "maximum" on DCC than when driven at maximum on DC - so it won't go as fast!!! My ZTC controller allows me to set maximum speed steps for each individual loco, so I set each up to reasonably represent the real locos. I allow my A4s to run at a scale 70mph or so, but set others lower. But in every case, I have left the decoder settings on their factory defaults. |
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Geoff R Member
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Petermac wrote: Will programming CV29 change the individual bits in a pre-set order ? i.e. If I set it to say 7, will it know that I want (for example), bit 1 at 0, bit 2 at 1 and so on until it totals 7 or will it just mess them all up to make 7, whatever the order ? CV29 (and every other CV for that matter) is an 8 bit register. In the dim and distant past I ran a "human" computer simulation for 7 year olds in my wife's classroom and I illustrated registers and their values like so:- We pretended that a row of desks represented a row of 8 identical terraced houses, each with their own house number. The first one is number 1, and the last number 8. Each house starts off empty. (No one sitting at the any of the 8 desks) We then take 8 children and give each one a binary value by hanging a label around their neck. One is 1, another 2, a third 4, the fourth 8, the fifth 16, the sixth 32, the seventh 64 and the eighth 128. They each live in one of the eight houses, value 1 in house number 1, value 2 in house 2, value 4 in house 3, right up to value 128 in house number 8. We then played a game to make up numbers from zero to 255. The children had to enter their house (actually sit at a desk) depending on the number on the blackboard. For zero all houses (desks) remained empty. For the number 7, three children sat in their desks. They were values 1, 2 and 4 and they went into houses 1, 2 and 3 respectively. For the number 248 (interesting number to choose!), five children would have sat in their desks, being values 128, 64, 32, 16 and 8 sitting in houses 8, 7, 6, 5, and 4 respectively - note that this is the opposite occupation to 7 (248 + 7 = 255 !!!!!) And so it is for CV29 on your decoder. Each bit is a house, and each has a different value. If you want to set bits 1, 2 and 3, you program CV29 with 7. (bits 4,5,6,7,and 8 will then all be zero - empty houses!) If you want to set bits 2,3 and 4 (the default settings) you program CV29 with 14, leaving bits 1,5,6,7 and 8 at zero. Any help? |
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John Dew Full Member
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Masterful Geoff I dont know about Peter but I found it to be the clearest explanation of the principal CVs I have read.........I did like the reference to 248 by the way! I dont entirely agree with you about not adjusting the speed CVs with Lenz chips.....I do (but find it far easier and predictable that TCS) .......its probably because of all streamlined LNER jobs as opposed to my muck and grime where I dont like any loco to go faster than 35mph  ..............whatever I dont want to quibble or detract in any way from an excellent post.Kind Regards ____________________ John Granby III Lenz DCC,RR&Co Gold V9 B1 Windows 10 |
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Petermac Moderator
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I too found your explanations very clear and easy to understand Geoff - many, many thanks. Your explanation of how CV 29 works was, as John said, masterful - I want to go off and get 8 kids now but I fear I'm too old ........... I can at least go half way and build 8 terraced houses - thanks to John Wiffen .........I'll call them "On", "Off", "Normally Fwd", "Normally Rev", "DC Compatible" etc. etc...........  On my way home from Rotary tonight I thought I'd try resetting the decoder to factory defaults and start again. You've confirmed that it's the right move. I'll then see what happens using these values. It's very interesting that you've never altered yours and maybe, for my A3 and A4, the same will apply. I can similarly understand why John would want to reduce his top speeds given his modelled location. Regarding the top speed John, it is the top speed rather than the manner in which it attains it. Perhaps Geoff has the answer. The DC controller is an old H & M single track controller and I suppose it's quite possible it supplies in excess of the 12v claimed. I never thought about that - one tends to believe what it says on the packet................ I'll certainly look carefully for any kind of binding - it didn't do it before I took the body off so I'm rather suspicious. On the other hand, could it be related to the back EMF ? Your "binding/hopping" is what I'd call "hunting". It moves in slight leaps rather than smoothly - as if the brakes are being constantly applied and released. I mustn't over-exaggerate the condition. It's certainly there but not a dramatic gait.I have printed off the DCC Concepts notes and, as you say, some parts (the simple bits) are clear and useful - but also easy to assimilate. Then it gets complicated suggesting dividing speed steps by the track voltage and ending up with 1/64th volt etc. etc. As with most things "unknown", I wish we could start in layman's terms before moving onto binary logs etc. Geoff's houses do that admirably - but are the windows open or closed ..............  I shall probably invest in Ian Morton's book - if not for CV's then for other "useful" facts and figures. I suspect he writes for idiots with hammers .................. ____________________ 'Petermac |
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Petermac Moderator
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Bunch of flowers on the way Mr Roberts......... I reset the decoder to factory defaults, re-addressed it and away she goes - sweet as a pea. I did find some slight bending on the connecting rods caused by some ham-fisted idiot with hands bigger than shovels and as steady as an earthquake. This was straightened by very gentle persuasion with a screwdriver or pair of small pliers - photos to follow perhaps tomorrow (more RLW tonight so no time - ugh but someone's got to keep these poor wine growers from starving .... )I'm not going to tell you how I corrected the slow speed - I'll let you have some guesses. The cryptic clue is: I know a lot more about Function 3 on a Lenz Silver decoder now ......... It's amazing what you find out if you read instructions .......____________________ 'Petermac |
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Geoff R Member
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Glad the reset did the trick, Peter. I have read that it is worth doing that even when the decoder is supposedly brand new - just in case! Careful now - not too much haste in using those extra Lenz functions. Now that you have discovered F3, you will be wanting to try F4 next!! Sadly, whilst ESU have the same function as the Lenz does on F3, I have found that the preloaded sound chips in both the Bachmann and Hornby locos that I have seem to use several different F numbers. I guess a standard would have been too much to hope for. Sadly on Bachmann's A1 it is F11, and my controller will only operate up to F8, so I have to drive very carefully!! |
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Iansa Member 
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Hi peter, Do you have the LH100 hand set.? If so I will try to simplify things a little. When you go into CV29 you will notice a row of small numbers bottom of screen which are the 8 bits in CV29. With 100 just press each number to turn that bit on/off and as ea number is pressed you will notice the value for that bit apear top right of screen. So with the LH100 you don't need to know the value for ea bit. Just turn it on/off by pressing the number the lenz will do it for you. If the small number shows it is on. Not showing means off. When you have numbers (value) you want press enter. It is done. Here is how I set my locos up Bit 1 = 28/128 speed steps Value =2 Bit 4= complex speed curve Value =16 Don't worry about this one yet just use CVs 2-5-6 Bit 5 = 4 digit addressing Value = 32 Add those values together = Total value of 50. All other bits in CV29 = 0 or not turned on. If I am not using a LH100 to program I put value of 50 in CV29. If you are not using the complex 28 step speed curve I wouldsuggest Bit 1= 28/128 speed step = on value 2 If using 4 digit address Bit 5= on value 32 Giving a total of 34 If not using 4 digit address leave bit 5 off value 0 Which means you will only need Bit1 on value of 2 in CV29. Hope this helps. Cheers Ian PS If it does not go right reset decoder and start again. ____________________ Any DCC is better than no DCC |
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Petermac Moderator
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Thanks Ian - that does help a great deal. I do have the LH100 Hanset so it all slots into place nicely. All these little "snippets" are certainly helping me to gain a better understanding of things. I got in a muddle with the Function 3 because, at some stage, I must have pressed button 3 and hadn't remembered that simply pressing the button activated the function. I "cut my teeth" on the EZ starter unit and to access the functions there, you had to first press the "F" key ...................... Maybe too many things going on at once in too small a brain ...... ____________________ 'Petermac |
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John Dew Full Member
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Glad it got sorted Peter....................Geoff you are a great exponent of the KISS principle! Thanks for the tip about decoder reset.......I tend to do it as a solution of last resort.........doing it as preventive maintenance immediately after installation sounds a good idea ____________________ John Granby III Lenz DCC,RR&Co Gold V9 B1 Windows 10 |
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Paul Chetter Full Member
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John Dew wrote: Glad it got sorted Peter....................Geoff you are a great exponent of the KISS principle! John, I realise that this is a little out of context, but we all tend to carry on doing the same things that seem to be beneficial. You may have no plans to run sound decoders, but in case you do....... I would not advocate this approach for user-programmable sound decoders. Many pre-loaded sound projects require non-standard CVs to work correctly. Re-setting to factory defaults would not lose the sounds - usually - but may well effect how the sounds react to control inputs. Both ESU and Zimo have ways to 'lock' the project, or to provide a means for 'safe' re-set which restores the sound project's default CVs rather than 'factory', but it would be advisable to check that the sound author has enable this facility during the original compilation. Kind regards, Paul |
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