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E-link voltage problem

Roland-367323

By Roland-367323
in Hornby DCC

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Roland-367323 Rookie

Roland-367323

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Posted

Hi guys. I am a total beginner with model railroads, and even more with dcc. I have just recently learnt about the HM7000 decoders, and I bought one for my Lima ICE 1 loco. But, as I am just at my beginner phase, i don’t have a layout yet, just a basic starter set track. Because of that I bought the E-link, to be able to have DCC (Railmaster) program, signal etc. (i know that the whole situation is a mess 😅).

anyway, after installing the decoder, setting up just a straight short track to try out the chip and do some programming, the system does not want to work. The loco was able to turn on the light, on the HM DCC 7000 app, but when I accelerated, it just jerked and did not move. I could not figure it out what the problem can be. So after readon about a bit, i bought a voltage multimeter. And shockingly i read just 0.10-0.12v from the tracks… i am confused. I used the cable received with the E-link. The connector seems a bit dodgy tho (track, Hornby R-8241).

when i read the voltage on my analogue starter set, at the max speed it was reading 14.92v, which supposed to be.

can someone please help me with this? 🙈

i would appreciate it :)

Thank you

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RDS Grand Master

RDS

Posted
Posted

Hi Roland and welcome to the Forum

If you are measuring the voltage across the track on the DC scale (assuming you are using the Power Supply that came with eLink), that is the type of reading you will get because DCC produces a 'type of' AC voltage. You should get about 18v if you use the AC scale.

You don't mention that you have loaded the RailMaster software on a Windows PC.


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P-Henny Mentor

P-Henny

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There can only be two reasons for getting a voltage reading of about 0.1v. Either the eLink and/or power supply is faulty and/or not communicating with the RailMaster software OR you have set your meter on the DC Voltage range.

DCC track voltage is a form of AC called Bi-polar. The webpage Hyperlink below shows an image of what a typical DCC Bi-polar waveform looks like.

This is a sample DCC waveform.

Notice how the width of the pulses varies. It is these width variations that contain the digital DCC commands that are decoded by the DCC decoder to convert the DCC commands into actions such as turning on lights and moving the motor.

The Meter must be set to the AC Voltage range to display a DCC voltage, but because DCC is a square waveform (see image) at a nominal 7,000 Hz frequency and not Sinusoidal AC at 50 Hz the reading you get will vary with the meter being used and may display a reading lower than 18 volts. The output of an eLink displayed on an AC meter is in my experience more likely to be 13v to 15v AC.

If the starter set track you are using for testing is a DC Analogue starter set, then you MUST flip open the cover on the power track piece and remove the capacitor soldered across the rail connections. This capacitor will disrupt the DCC commands in the waveform by distorting it.

The capacitor may be brown but might be blue, it may be round but might be square. It will be the only electronic component found under the track piece cover.

If you are using the R8241 mentioned in your post, then that is digitally compliant and already has the capacitor removed.

P.S As RDS mentions in his reply. Have you installed RailMaster software, have you installed the eLink driver in Windows. If you have, then RailMaster should start without any error messages and the controller symbol in the top right corner of RailMaster should be green. If this pre-requisite is not so, then there will not be any DCC commands being sent to the track as the eLink can not function unless it is communicating with RailMaster.

If the controller symbol icon is not green, then read up on FAQ1 located in the 'RailMaster FAQ Index' pinned sticky thread at the top of the RailMaster forum where your eLink question should have (ideally) been posted.

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P-Henny Mentor

P-Henny

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Being able to see what you are doing on the PC screen in RailMaster is far more helpful to us than seeing what the loco is not doing.

The final frame in the third video seemed to show the throttle slider at near zero, so no wonder the loco wasn't moving much. I can just see when paused that the controller symbol icon is green, so this indicates that the eLink driver must be loaded and correctly detected.

In DCC, if the loco is not a good runner on DC then it will never work well on DCC. DC running can tolerate higher levels of dirt & grime on the track rails and wheels compared to DCC, so the first task is to clean (thoroughly with a track rubber and also with a volatile cleaner such as IsoPropyl Alcohol [iPA] or Meths) rails, wheels and also eLink & track wire connections. Then test the loco on DC (eLink disconnected from track), preferably with the decoder removed, but it should also work on DC if DC enabled in CV29. DC enabled is, I believe, disabled by default on HM7000 Decoders hence the remove decoder recommendation when testing on DC. Remember to reinstate the blanking plate (DC Bypass) in the loco when the decoder is removed.

Also to help analyse your issue, provide screenshots of the 'Locomotive Settings' screen for your loco.

Although the top of the throttle slider had a pink band and not a green band, I am not too concerned about that as the HM7000 decoders are not yet in the RM database. A green band would have indicated that the loco and decoder had been selected from the Hornby database, but that is not essential for successful loco operation.

You haven't updated us with what voltage reading you are getting on your meter's AC Voltage scale.

Overall, given that the loco starts to move in the first video I suspect that your issue is highly likely to be caused by dirt & grime on track rails & wheels OR badly adjusted wheel pickups. A DC running test could help confirm or disprove this theory.

EDIT: This reply was posted before your post with the photos appeared on my view of this forum thread. The 6.5 volts does appear to be a tad on the low side ..... cause could just be your meter AC calibration is more tightly focused on Sinusoidal 50 Hz AC and therefore struggling to read the Bi-polar DCC, but could possibly also be an indicator of poor electrical conductivity due to dirt & grime.

What AC reading do you get without the loco on the track, if it jumps up to double the 6.5v value your loco may have a very low resistance presented to the track fault.

Is your eLink Power Supply the supplied 1 Amp supply or the 4 Amp P9300 upgrade supply?

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P-Henny Mentor

P-Henny

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Posted

If you can borrow another meter and still get a voltage the same (6.5v) or less than 9 volts, then I would start to suspect that the eLink is faulty. A voltage of 6.5 volts is a very low reading for DCC. Faulty eLinks from new are not unheard of, but once working they do tend to be reliable if not abused.

Just to double check, is the measured output of the 1 Amp power supply 15 volts DC +/- 0.4 volts. If the power supply DC output is less than 13 or 14 volts then it is clearly faulty and maybe the reason for the 6.5 volt AC track output of the eLink.

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96RAF Grand Master

96RAF

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Posted

The 1-amp PSU drops its output voltage in self protection mode, so it could be the PSU has gone faulty. Check its output at the jack plug as Paul suggests, noting that that output is DC this time.

The assumed voltage you see on the AC scale is dependant upon the sampling rate of your meter, which will be in the spec. There can be a very wide variation.

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