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Hi all.
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I am experiencing false triggering of inputs from section tracks furthest from a DR4088 which I suspect is caused by using long lengths of parallel cables using figure 8 wire as Kato Connectors:
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In some cases I have 3 connected in series making cables 2.5m long.
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Is there any way that the input of DR4088 can be desensitised so that it triggers at a greater current draw that the 2mA that is stated in the manual?
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I do not have an Rrampmeter to determine if any current is drawn in an unoccupied state.
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If I cannot then I will need to split the cables down the centre or add a new DR4088 closer to the offending lengths of track.
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Those connections with only single length of cable are fine.
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Many thanks
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Colin
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Colin, You can reduce the sensitivity of the DR4088 by adding resistors to any or all of the outputs.? Depending on how much you need, you could go from like 300 up to 2000.? I have added some photo examples in the Photo Album.?? /g/Digikeijs/album?id=238410Ryan ?
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Ryan.
Thank you for the reply/solution.
I will try that when I am next able to access the layout which will not be until Friday.
I am interested to know the theory as to why that works.
Colin.
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Colin
What Ryan has done is create a second circuit in parallel with the DR4088LN detector circuit.? This will cause some of the current flowing from the track block to the DR4088LN to go through the resistor and the rest of it to go through the detector circuit, and hence reduce the current going through the detector to avoid false detections.? Hopefully, the DR4088LN will only 'detect' when a loco is in the block and drawing significant current.? If you search with 'current in a parallel circuit' on a web browser, you will find articles explaining how this works.
What isn't shown in Ryan's pictures is that you still connect the track output?from the command station/booster through the DR4088LN as you would have without the resistors being in the picture. With the resistors there will be two connections to each of the connectors on the green strips of the DR4088LN - one for the resistor and one from the track block.? The other wire from the track output connects to the common associated with the green connector for the block you are wiring.? This will create parallel circuit for each detection block.? You may need to use resistors of different values than Ryan suggests to make the detection work - experimentation may be required for your situation, but start with Ryan's suggested resistor value.
The very nature of DCC with its square wave alternating current will generate a phantom current in wires to track blocks even when there is no loco present.? There are techniques to minimize this current - look at sources like the 'DCC Wiki' () and 'Wiring for DCC' () for more information on this topic.
I hope this helps.? If anyone else can provide more information on this to Colin, please do.
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On 15/01/2020 17:19, Jay Lennox wrote: Colin
What Ryan has done is create a second circuit in parallel with the DR4088LN detector circuit.? This will cause some of the current flowing from the track block to the DR4088LN to go through the resistor and the rest of it to go through the detector circuit, and hence reduce the current going through the detector to avoid false detections. Hopefully, the DR4088LN will only 'detect' when a loco is in the block and drawing significant current.? If you search with 'current in a parallel circuit' on a web browser, you will find articles explaining how this works.
What isn't shown in Ryan's pictures is that you still connect the track output?from the command station/booster through the DR4088LN as you would have without the resistors being in the picture. With the resistors there will be two connections to each of the connectors on the green strips of the DR4088LN - one for the resistor and one from the track block.? The other wire from the track output connects to the common associated with the green connector for the block you are wiring.? This will create parallel circuit for each detection block. You may need to use resistors of different values than Ryan suggests to make the detection work - experimentation may be required for your situation, but start with Ryan's suggested resistor value.
I find that the slightest electronic component across a track will trigger the detector. These range from train tech signals to even the little led circuit detector (not that you keep this on the rail). But it shows what little current triggers the device. So I wonder what happens when these resistors are strapped across, since there will be a 1k approx path from each block to the others (470 + 470). Depending on what impedance each of the outputs are, there is a chance that a loco in one block could trigger the sensors in others via this back path. It probably depends on the value of the which, as mentioned, is set empirically. Time to experiment, me thinks. Maybe Digikeijs could look into providing trimming on each output? -- Chris
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Detectors will trigger at 1mA or less so a LED, signal, etc. connected to a track will trigger the detector. Even wet ballast or a finger can be detected. The common detectable wheelsets use 10K resistors which is why it has to be sensitive. Normally you don't connect anything but track after the detector. Some of my blocks have turnouts that put a 4k7 resistor across the track when set off the mainline to set signals to stop and proceed if set enter the yard.
Mike
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Does the YaMoRC version of the DR4088CS, the?, solve the issue of needing to add the 500 ohm resistors between the output and common, or do you still need to adjust the sensitivity of the detection circuits?
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--
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Hi,
since the YD6016xx-CS modules are?NOT?just a Version. In fact other than being current sensing feedback unit, they have nothing to do with eachother¡ ?
to your question: the YD6016xx-CS all have a very effective noise-suppression system on board.
fun part: it hardly decreases the real sensitivity. That stays nicely at 1-1.5mA.
greets,
Karst
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Karst, Thanks for the information, looks like I need one more current sensing version, so it will be nice not to need to add the resistors. And while I get why you are correcting people, I was using "version" that same way you would say the NCE version of the AR-1 versus the Digitrax version of the AR-1. Or the NCE version of the BD20 versus another manufactures version of a BD-20. People are going to compare the YaMoRC products to similar/related versions from Digikeijs, Digitrax, NCE, etc... and talk about the similarities and differences. Thanks!! --
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Welcome :)
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The comparison by itself is ok, no problem.
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But we had a lot of not so nice emails, phone calls and even "visits" of people thinking/assuming YaMoRC is "Just Another VERSION of Digikeijs" .... ;)?
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Greets,
Karst
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Ryan: I have read about adding resistors to the DR4088 to desensitize the device but never understood how this was to be accomplished until I saw your photos. Awesome, thanks!!!
Just to help me understand further, though, it was my impression that each of the 1-8, 9-16 detection connections were to be separate from each other; ?the way you have them soldered together to the common ¡®C¡¯ is they are all tied together, will then a detection on any one them show detection on all of them, thus making it a tad confusing as to which block is occupied?
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You are not ¡®tying¡¯ the 1-8 outputs (or 9-16) together, they remain completely separate as they are today. You are placing a shunt resistors between the feedback e.g. feedback 1 and the C terminal for that bank.?
This means that most of the current shunts through the resistor rather than going through the DR4088xx.?
[Edited Message Follows]
Ryan: I have read about adding resistors to the DR4088 to desensitize the device but never understood how this was to be accomplished until I saw your photos. Awesome, thanks!!!
Just to help me understand further, though, it was my impression that each of the 1-8, 9-16 detection connections were to be separate from each other; ?the way you have them soldered together to the common ¡®C¡¯ is they are all tied together, will then a detection on any one them show detection on all of them, thus making it a tad confusing as to which block is occupied?
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Iain:? To help my understanding further please.? The 1-8 or 9-16 'outputs' are not bothered by the fact they share the same wire and still can determine which block is occupied.? How does one connect to the layout for detection.? I would guess each section (block) needs its own feeders, but do they all tie (via drop feeders) to that same wire (acting like a bus wire)?? Thanks...
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The track feeds for the layout come from the terminals marked 1 - 8 and 9 - 16, in exactly the same way as they do now.?
Iain:? To help my understanding further please.? The 1-8 or 9-16 'outputs' are not bothered by the fact they share the same wire and still can determine which block is occupied.? How does one connect to the layout for detection.? I would guess each section (block) needs its own feeders, but do they all tie (via drop feeders) to that same wire (acting like a bus wire)?? Thanks...
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Iain: Thanks again.? Using Ryan's photo as guide (see link below), I trust then that each wire on a resistor coming from 1-8 and 9-16 point to where the connection from the layout would be, in other words the drop feeders from the layout would connect separately to each wire coming from 1-8 or 9-16. What I can't get through my brain (sorry) is if all the drop feeders from the layout above are soldered (or will be soldered together given all resistors from 1-8 connect to the same 'C' wire) how does the DR4088 unit determine if 1, 4, 6, or 8 was tripped (occupied) given each of 1,4, 6 or 8 are soldered to the same wire going to 'C'? In the DR4088 manual, the wires from 1-8, 9-16 do not connect to the 'C' wire.? Please help? /g/Digikeijs/photo/238410/2781881/4088b.jpg?p=Created%2C%2C%2C20%2C2%2C0%2C0Don
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The layout wires from 1-8 and 9-16 are NOT connected to the C terminals. These wires go to the layout track and the motor draws current. Some of that current flows through the DR4088xx and the rest flows through the resistor.
I can assure you without fear of contradiction that this method of shunting some of the current through a resistor works perfectly. It is used throughout the world for many, many reasons.? A good example is an ammeter. The actual gauge takes milliamperes to operate and the rest of the current travels through a shunt resistor - this ¡®trick¡¯ with the DR4088xx does exactly the same with a small percentage of the current going through the DR4088xx and the rest going through the resistor. The smalll percentage is too low to trip the DR4088xx when the current drawn is extremely low e.g. phantom occupation and too low to make the DR4088xx think there is occupation. When there is real occupation the small percentage is large enough to cause the DR4088xx to sense occupation, the rest of the current is shunted through the resistance.
Iain:
Thanks again.? Using Ryan's photo as guide (see link below), I trust then that each wire on a resistor coming from 1-8 and 9-16 point to where the connection from the layout would be, in other words the drop feeders from the layout would connect separately to each wire coming from 1-8 or 9-16.
What I can't get through my brain (sorry) is if all the drop feeders from the layout above are soldered (or will be soldered together given all resistors from 1-8 connect to the same 'C' wire) how does the DR4088 unit determine if 1, 4, 6, or 8 was tripped (occupied) given each of 1,4, 6 or 8 are soldered to the same wire going to 'C'?
In the DR4088 manual, the wires from 1-8, 9-16 do not connect to the 'C' wire.? Please help?
/g/Digikeijs/photo/238410/2781881/4088b.jpg?p=Created%2C%2C%2C20%2C2%2C0%2C0
Don
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Iain: I appreciate all the advice, thanks for helping me.
Still confusing to me, all of the wires from 1-8 or 9-16 are soldered to the 'C' in Ryan's photographs, all are shown to be tied (soldered) together through that single wire going to 'C' in the photograph.? There is no isolation/separation I can see in the way these are soldered together, alas (I am so confused) how then do drop-wires attach to separately to each of 1-8, 9-16 (I can't understand how this is done given what I see in the photograph?? Does a second wire (direct from each layout detection block) get inserted in each of the connections 1-8 and 9-16?
Don
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I repeat, the wires in Ryan¡¯s picture are NOT connected from the 1-8 terminals to the C terminals - one end of the resistor goes into the 1-8 and the other into the C terminal.
Just do what is build what is shown in the picture and connect your layout as normal - it will work.
Iain: I appreciate all the advice, thanks for helping me.
Still confusing to me, all of the wires from 1-8 or 9-16 are soldered to the 'C' in Ryan's photographs, all are shown to be tied (soldered) together through that single wire going to 'C' in the photograph.? There is no isolation/separation I can see in the way these are soldered together, alas (I am so confused) how then do drop-wires attach to separately to each of 1-8, 9-16 (I can't understand how this is done given what I see in the photograph?? Does a second wire (direct from each layout detection block) get inserted in each of the connections 1-8 and 9-16?
Don
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Hi Iain,
I think it is correct that you don¡¯t ¡®need¡¯ to resistor all the feedbacks ?
I¡¯ve just had to fit a resistor to one feedback on one of my DR4088s - the rest are OK ??
Cheers,
Alastair
Sent from my mobile device - apologies for any misspelling, misinformation or mistakes
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On 19 Sep 2023, at 21:35, Iain Morrison <w.iain.morrison@...> wrote:
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I repeat, the wires in Ryan¡¯s picture are NOT connected from the 1-8 terminals to the C terminals - one end of the resistor goes into the 1-8 and the other into the C terminal.
Just do what is build what is shown in the picture and connect your layout as normal - it will work.
Many Thanks
Iain Morrison
Iain: I appreciate all the advice, thanks for helping me.
Still confusing to me, all of the wires from 1-8 or 9-16 are soldered to the 'C' in Ryan's photographs, all are shown to be tied (soldered) together through that single wire going to 'C' in the photograph.? There is no isolation/separation I can see in the
way these are soldered together, alas (I am so confused) how then do drop-wires attach to separately to each of 1-8, 9-16 (I can't understand how this is done given what I see in the photograph?? Does a second wire (direct from each layout detection block)
get inserted in each of the connections 1-8 and 9-16?
Don
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Iain:? I will trust you, but how then do drop feeders get connected to the DR4088 using this methodology?? Does each track feeder (from each separate block) get inserted into the same connections occupied by the resistor in each of 1-8 and 9-16?
Thanks again, Don
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