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Old 09-04-2018, 08:09 AM   #1
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Default Volt & amp meter on DCC

I have decided to wire my layout in 4 zones & wondered if anyone had fitted an eBay digital volt amp meters. I will be making up a small control panel & I was going to put one on each of the zones as a couple are long runs of cable. Now these 10amp 4-30V DC V/A meters have a built in shunt & wasn't sure if this would effect the DCC signal to the track?. Any advise would be a help. Thanks
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Old 09-04-2018, 08:26 AM   #2
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They won't work on DCC as it's a type of AC and also a high frequency digital signal. The only meter that I know of that works is a RRamp meter http://www.digitrains.co.uk/ecommerc...pmeter-v2.aspx

Some multimeters can measure the voltage quite accurately but I don't think they can measure DCC current.
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Old 09-04-2018, 08:31 AM   #3
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For rough measuring purposes a DCC signal is essentially AC with a square variable width rather than a true AC periodic elliptical waveform, so your DC meter won’t give anything like a true reading. Compare using your multi-meter on DC and AC volts scales.

I couldn’t find a 10A-30V AC combo meter and wrongly bought a 10A-300V one which is also useless for the same task as you intend.

To read DCC correctly you need an rramp meter.

Rob
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Last edited by RAFHAAA96; 09-04-2018 at 08:48 AM. Reason: Added rramp meter
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Old 09-04-2018, 10:07 AM   #4
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RRAmp meter is AFAIK the only fixed method of measuring DCC volts and Current.
Other panel meters (digital or analogue) will either not work or not be accurate! They need to be able to operate at around 10KHz and most will be designed for domestic frequency of 50Hz (UK/Europe) or 60Hz (American)
Example of RRAmp panel meter... Link to example
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Old 09-04-2018, 10:53 AM   #5
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One of these, they come with or with out a Cover go for the cover type as cutting the hole for the LED Display and the LED's is a real pain....The DCC System is a NCE with a SB5 Booster.....
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Old 09-04-2018, 04:34 PM   #6
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Ah, well done everyone & thanks for the links. It would be nice to monitor each area/zone of the layout. I sent off an email to the guys at Digitrain to see if there is an alternative to buying more than one. IE: possibly a 5 position double pole rotary switch so i can select the area to monitor easily. I will post, when i hear. Ah! That was quick & some food for thought.

Hello sir, use V1 meters mounted in a panel, they're cheaper. The V2 is a cased version of exactly the same meter with additional test leads which you might not need. Otherwise a bit of nifty wiring so you can switch the bus power through it from each area in turn could be devised perhaps. For it to measure current it has to be in line not in parallel like a volt meter, that's the only tricky bit in your design.
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Old 10-04-2018, 07:37 AM   #7
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This is the basic wiring diagram for these combo meters, noting the shunt would normally go where the cut is shown.

The one I have passes the wires through a current sensor ring rather than putting the meter in direct series.

Edit...

You may also like to read this thread http://model-railroad-hobbyist.com/node/21847 which details exactly what you are trying to do and lists the pitfalls.



Rob
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Last edited by RAFHAAA96; 10-04-2018 at 07:49 AM. Reason: Extra info added
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Old 10-04-2018, 05:57 PM   #8
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Quote:
Originally Posted by RAFHAAA96 View Post
This is the basic wiring diagram for these combo meters, noting the shunt would normally go where the cut is shown.

The one I have passes the wires through a current sensor ring rather than putting the meter in direct series.

Edit...

You may also like to read this thread http://model-railroad-hobbyist.com/node/21847 which details exactly what you are trying to do and lists the pitfalls.



Rob
Thanks Rob. So connect a current transformer the same as if it was the shunt terminals. Has the current trany to have any particular values?
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Old 11-04-2018, 07:39 AM   #9
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Have a read of this
http://www.members.optusnet.com.au/n...DCC_Meters.htm

it maybe helpful
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DC is good - so is DCC - it depends on your operating process.
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Old 11-04-2018, 06:13 PM   #10
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Quote:
Originally Posted by Sol View Post
Have a read of this
http://www.members.optusnet.com.au/n...DCC_Meters.htm

it maybe helpful
Ah, i had seen this one & i just got the bridge rectifier in the post today. Will set it up over the weekend to see how we go.
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