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This page is very much “under construction” – However we’ve made a start and will add more soon!
It seems that every technology gains its own “jargon”, and DCC is no exception. Because the language of DCC is still evolving, I can never hope to make this totally comprehensive, but I will do my best to re-visit this page regularly and “update” its content as new information comes to hand.
As with all pages on my website, if you have a positive suggestion, correction, addition, better description of just a word of encouragement please don’t hesitate to contact me…
KEY
There are varied sources of “new words” for a sophisticated concept.
• The technology that allowed it to be created – In this case, computer related words
• The market for which it is intended – Model Railway terminology
• The brands that create the product – “in-house” or proprietary language
• The support industry – A mix of “techspeak” and “Marketingese” terms
• The consumers – colloquial, affectionate or convenient words
Therefore, where possible I’ve added a “key” alongside each word or phrase to let you know where to look for a more comprehensive explanation, or where to dig for more related data.
SEARCHING THIS PAGE
Explorer contains a useful “SEARCH” facility.
Simply press “CTRL” and F button together, and a “search” box will pop up on your screen. Type in the word you are looking for and press the “Find Next” button. You will be taken to the information you are seeking. If you do NOT find he exact word, try either a word with similar meaning or a related word (For example, if you are seeking data on wiring your layout then: Power / Bus / Power Bus / wire / AWG / Amps will all take you to related pages).
BRAND related keys
| (DGT) = Digitrax | (NCE) = NCE Corp | (LNZ) = Lenz |
| (ATL) = Atlas | (ZTC)= ZTC Controls | (ZIM) = Zimo |
| (UHL) = Uhlenbrock | (TCS) = Train Control Systems | (ESU) = ESU Lokpilot/Loksound |
| (STX) = Soundtraxx | | |
OTHER keys
| (RUS) = Modelling in USA | (RUK) = Modelling in UK | (REU) = Modelling in Europe |
| (CMP) = Computing | (DCC) = Common DCC term | (GEN) = Generic |
| Key | Term | Description/Explaination |
| (DCC) | BEMF | A decoder feature: BEMF both assists slow running and provides proportional load compensation to the motor drive. BEMF features do vary brand by brand, however BEMF operates by sensing load and it then compensates for variances by adjusting power provided to the motor under varying conditions. |
| (DCC) | Brake on DC | A decoder feature: This is activated by rectifying the DCC signal in, for example, an isolated section before a signal or point of danger (say, a turnout/point seta against the train, end of line or at a red signal) When the decoder senses the “DC” voltage on the track it activates and slowly stops the loco using the decoders pre-set deceleration or momentum curve. When the obstruction or signal is cleared and the DCC signal is restored, the locomotive will automatically re-start and return to the original speed setting at a rate controlled by the preset acceleration curve programmed into the decoder. |
| (TCS) | Dither | A decoder feature: Dither assists slow running by injecting a variable pulse into the motor drive voltage. Dither is adjustable in both amplitude and frequency (refer to specific Decoder worksheets). Even loco’s with poor general starting characteristics can be greatly improved and are able to show excellent slow speed performance when Dither is correctly adjusted. Dither was invented by TCS |
| (DCC) | Droppers | The wires that connect the track to the “power Bus” are known as “Droppers” and can be somewhat finer than the main power bus as long as they are kept short (less than 300mm/1 foot).
Recommended wire gauge for droppers is 18 gauge/1.02mm2 is recommended for all layouts irrespective of size.
NEVER use wire below 22 gauge/0.64mm2 – it cannot withstand high currents. Because of the short length either solid or stranded is OK, although stranded wire will generally be more reliable long term (if a solid wire is “nicked” during stripping it becomes weak) |
| (DCC) | Power Bus | A generic DCC feature: A power bus is the connection between the power booster or combined booster/command station and the track. This should be made with wire able to deliver the full track voltage to the most distant part of the system with only very small voltage loss when under full load (track voltage @5 amps). It is recommended that the two wires of the track bus be either (a) twisted together @ appx 1 turn per 150mm or (b) separated by at least 150mm from each other. This avoids inductive resistance and lowers the risk of voltage drop.
The power bus should be joined to the track as frequently as is practical. General consensus from DCC users and manufacturers is that feed every track section (ie each yard/metre). The wires that connect the track to the “power Bus” are known as “Droppers” and can be somewhat finer than the main power bus as long as they are kept short (less than 300mm/1 foot).
Recommended wire gauges are:
Power Bus: The Power bus should ideally be stranded wire – AC “surface effect” does come into play slightly with DCC frequencies, so wire with lots of fine strands is a better choice than few heavy strands. (more strands, is better). The following sizes are recommended:
Large layout 12g/2.05mm2 , Medium 14g/1.62mm2
Small 16g/1.29mm2 (If unsure always user larger option)
Droppers: 18 gauge/1.02mm2 or 20 gauge/0.81mm2 is recommended for all layouts. NEVER use wire below 22 gauge/0.64mm2 – it cannot withstand high currents. Because of the short length either solid or stranded is OK, although stranded wire will generally be more reliable long term particularly for a portable layout or where movement exists. (if a solid wire is “nicked” during stripping it becomes weak). |
| (DCC) | CV | CV = "Configuration variable" - These are special information storage locations in your decoders. By programming various CV's, you can control each decoder's attributes or performance characteristics. CV's store information such as the decoder's address, lighting control options, start voltage and many more features. Once you have programmed these characteristics, the decoders "remember" them until you change them again. It is worth checking each decoder against its specific instruction/worksheet as whilst he NMRA’s "Standards and RPs" define the usage of many CVs, others are manufacturer defined, and differ between decoder brands in application and use. |
| (DCC) | Speed Steps | There are three standard "Speed Step" settings, as follows. A "speed step" is an increment of acceleration and deceleration – each step is one level faster or slower. More means smoother. Speed step selection can be controlled via both Decoder CV’s and controller settings – see documentation for your equipment.
14 step: This was the original option for DCC, and is a "hangover" from the early days. Whilst many decoders still offer this option it will progressively disappear from decoders, and new control systems may NOT offer this option in future.
28 step: At 28 step settings loco control will be smooth and stepping will not be noticed. It will give best performance for shunting/switching, and may operators set all their loco’s to this setting.
128 step: 128 step control is super smooth, and really makes the best of a quality drive system in your loco’s. 128 step MAY give best slow speed running for some loco’s. 128 step is technically significant in speed control over 14 or 28 step operation and is best used for main line running, where acceleration momentum is pre-programmed or speed curves / matching of loco’s is important as in consisting, double heading and banking.
ALL modern decoders offer both 28/128 speed steps, and most control systems allow either automatic acceptance of speed steps ex decoder settings and front panel selection "at the controller"
NOTE: It is best to decide on a "speed step standard" and keep to it. Mis-matching of decoder and controller settings gives unpredictable results, including intermittent lighting operation and random control problems such as unexplained starting and stopping. |
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