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lnet_current_source-en [2018/11/12 08:56] (current)
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 +====== LNet current source ======
 +[[english|{{ ​ rocrail-logo-35.png}}]]
 +[[english|Content]] -> [[hardware-en|Hardware]] -> [[hardware-en#​locoio|GCA]]
 +  *  [[mgv-overview-en|The GCA modules]] ​
  
 + \\
 +
 +^^^^By Peter Giling ^^^^
 + \\
 +===== current source =====
 +\\
 +To start with, this current source has NOTHING to do with the power that any LNet unit needs to get working.\\
 +Communication in LNet and most LocoNet devices is done via one single wire.\\
 +This wire is carrying between 10 and 15 Volts, and will be short circuited to ground when communication is taking place.\\
 +Some available products feed this 10-15 V via a simple resistor.\\
 +But the original way of achieving this, is to feed this 10-15V via a so called current source.\\
 +It is basicly doing the same as a simple resistor, but it limits the current in the short circuit situation \\
 +to 15 mAmp maximum.\\
 +This will avoid that any wire resistance over the used cable will cause communication flaws.\\
 +This of course between certain limits.\\
 +There is a technical more important reason to do it this way, but there is no need to go that far in explanation.\\
 +
 +A problem could arise, when -for example- GCA85 or GCA101 or CAN_GCLN are connected to the LNet together with any central unit\\
 +like Twincenter, Intellibox and/or any of the available Digitrax units.\\
 +All these units contain some way of feeding this 15 mA to the LNet communication line.\\
 +These currrents are considered to add to each other, so the total current will be much higher than needed.\\
 +That is why GCA units all provide the option to shut off this current source.\\
 +When GCA85 or GCA101 or CAN_GCLN is the only main LNet unit, its current source should always be activated.\\
lnet_current_source-en.txt ยท Last modified: 2018/11/12 08:56 (external edit)