ADAPTING DC METERS TO DCC


Ed
 

I have recently switched over to DCC and would like to reuse as much of my old equipment as possible. I had volt and amp panel meters installed. Is it possible to adapt these meters for use in my DCC system? If so, what must I do?

Ed Robinson


Max Maginness
 

If you don't mind some inaccuracy, voltmeters are easy, just use a diode
bridge. It will then read the DCC voltage less about 1.4 volts. (AC ~
connections on the bridge to the DCC source and + and - to the voltmeter.
Any 1 amp bridge will do)



For an ammeter it's a bit trickier - and also what is the current rating,
remember that DCC is supplying several trains at once so you will typically
have higher currents than with DC.



Max



From: WiringForDCC@yahoogroups.com [mailto:WiringForDCC@yahoogroups.com] On
Behalf Of Ed
Sent: Monday, November 01, 2010 4:42 PM
To: WiringForDCC@yahoogroups.com
Subject: [WiringForDCC] ADAPTING DC METERS TO DCC





I have recently switched over to DCC and would like to reuse as much of my
old equipment as possible. I had volt and amp panel meters installed. Is it
possible to adapt these meters for use in my DCC system? If so, what must I
do?

Ed Robinson



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rg <richg_1998@...>
 

Below is a link to a DCC amp meter that uses a cheap digital multimeter but you might adapt the circuit for analog meters. I have not tried as all I use are these digital meters.

Click on Return to Main Page as this guy has loads of useful circuits.

http://home.cogeco.ca/~rpaisley4/DCCammeter10.html

Below is a DCC voltmeter by NCE, a DCC supplier. I use this circuit with a cheap digital multimeter.
http://jdb.psu.edu/nmra/dcc-voltmeter.html

More circuits to play with.
http://www.wiringfordcc.com/track.htm#a1

Do not know what your meter ratings are so you might have to experiment.

Rich



Inside every older person is a younger person wondering,
what happened?


Ed
 

Thanks Rich. Both my meters came from MicroMark. The voltmeter is +/- 20 volts and the ammeter is +/- 5 amps. No other specs provided.

Ed Robinson

--- In WiringForDCC@yahoogroups.com, rg <richg_1998@...> wrote:

Below is a link to a DCC amp meter that uses a cheap digital multimeter but you might adapt the circuit for analog meters. I have not tried as all I use are these digital meters.

Click on Return to Main Page as this guy has loads of useful circuits.

http://home.cogeco.ca/~rpaisley4/DCCammeter10.html

Below is a DCC voltmeter by NCE, a DCC supplier. I use this circuit with a cheap digital multimeter.
http://jdb.psu.edu/nmra/dcc-voltmeter.html

More circuits to play with.
http://www.wiringfordcc.com/track.htm#a1

Do not know what your meter ratings are so you might have to experiment.

Rich



Inside every older person is a younger person wondering,
what happened?


Max Maginness
 

These are not really that useful for DCC. The voltmeter circuits referred
to use DMM's with much higher resistance than the analog voltmeter you have.
It could be used as I suggested, but it will read only in one direction so
you will use only one side of the scale.



The ammeter might be used as it has sufficient current range, but again only
by using a diode bridge with some loss of track voltage.

Max







From: WiringForDCC@yahoogroups.com [mailto:WiringForDCC@yahoogroups.com] On
Behalf Of Ed
Sent: Monday, November 01, 2010 7:51 PM
To: WiringForDCC@yahoogroups.com
Subject: [WiringForDCC] Re: ADAPTING DC METERS TO DCC







Thanks Rich. Both my meters came from MicroMark. The voltmeter is +/- 20
volts and the ammeter is +/- 5 amps. No other specs provided.

Ed Robinson

--- In WiringForDCC@yahoogroups.com <mailto:WiringForDCC%40yahoogroups.com>
, rg <richg_1998@...> wrote:

Below is a link to a DCC amp meter that uses a cheap digital multimeter
but you might adapt the circuit for analog meters. I have not tried as all I
use are these digital meters.

Click on Return to Main Page as this guy has loads of useful circuits.

http://home.cogeco.ca/~rpaisley4/DCCammeter10.html

Below is a DCC voltmeter by NCE, a DCC supplier. I use this circuit with a
cheap digital multimeter.
http://jdb.psu.edu/nmra/dcc-voltmeter.html

More circuits to play with.
http://www.wiringfordcc.com/track.htm#a1

Do not know what your meter ratings are so you might have to experiment.

Rich



Inside every older person is a younger person wondering,
what happened?


_____

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Checked by AVG - www.avg.com
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rg <richg_1998@...>
 

I have never tried analog meters with DCC. I have some but they have not been used for many years.
At out club, our dispatchers panel still has a DC voltmeter and a amp meter that reads plus or minus and both needles do not move as DCC is essentially AC voltage.
“DCC is essentially AC voltage.” drives some rivet counters ballistic. No it is not, yes it is.
The digital meters I use I picked up for less than ten dollars each new and compare very well to my expensive digital meter which is hardly ever used anymore.
A photo of my DCC voltage tester adapter using the cheap meter.

[IMG]http://i98.photobucket.com/albums/l267/richg1998/DCC/IMG_1046.jpg[/IMG]

Can also be used in a DCC amp meter circuit.

http://home.cogeco.ca/~rpaisley4/DCCammeter10.html

Rich


Inside every older person is a younger person wondering,
what happened?


rg <richg_1998@...>
 

The voltmeter might work with the below circuit to readthe DCC track voltage. It might load down the circuit as digital meters have very little loading effect on circuits.

[IMG]http://i98.photobucket.com/albums/l267/richg1998/DCC/ADCCVoltmeterAdapter.gif[/IMG]

With a DCC amp meter circuit, I use the 20 milliamp setting.
Don't think your amp meter could be used for DCC.


Rich


Inside every older person is a younger person wondering,
what happened?


Dale Gloer
 

In my opinion, volt and ammeters are not very useful on DCC. Since track voltage is constant, about all a voltmeter will tell you is if track power is on or not. An LED across the track bus will give you the same information. An ammeter is really only useful when you make changes to the number of locomotives you run or for trouble shooting unexpected booster shutdowns. The circuit in this link http://home.cogeco.ca/~rpaisley4/DCCammeter10.html works well but requires a DMM rather than an analog meter. A suitable DMM can be had pretty cheaply. I agree with others that your analog meters are not useful for DCC.

Dale Gloer

--- In WiringForDCC@yahoogroups.com, "Ed" <lehighman@...> wrote:



Thanks Rich. Both my meters came from MicroMark. The voltmeter is +/- 20 volts and the ammeter is +/- 5 amps. No other specs provided.

Ed Robinson


--- In WiringForDCC@yahoogroups.com, rg <richg_1998@> wrote:

Below is a link to a DCC amp meter that uses a cheap digital multimeter but you might adapt the circuit for analog meters. I have not tried as all I use are these digital meters.

Click on Return to Main Page as this guy has loads of useful circuits.

http://home.cogeco.ca/~rpaisley4/DCCammeter10.html

Below is a DCC voltmeter by NCE, a DCC supplier. I use this circuit with a cheap digital multimeter.
http://jdb.psu.edu/nmra/dcc-voltmeter.html

More circuits to play with.
http://www.wiringfordcc.com/track.htm#a1

Do not know what your meter ratings are so you might have to experiment.

Rich



Inside every older person is a younger person wondering,
what happened?


rg <richg_1998@...>
 

I have already provided links to adapters that work with digital meters. I have a digital 'Scope that confirms the readings I get with my DCC adapters as used. This is not opinion, but experiences.

Rich


Inside every older person is a younger person wondering,
what happened?


emrldsky
 

Harbor Freight has a digital meter that is on sale from time to time for
less than $3.00. I have used it for voltage measurement on the tracks for
quite some time. It appears that it is "close enough for work" on the 200
VAC scale.



Mike G.


Ed
 

Looks like there is no useful purpose for these meters in my new layout. Thanks to everyone who responded.

Ed Robinson

--- In WiringForDCC@yahoogroups.com, rg <richg_1998@...> wrote:

I have already provided links to adapters that work with digital meters. I have a digital 'Scope that confirms the readings I get with my DCC adapters as used. This is not opinion, but experiences.

Rich


Inside every older person is a younger person wondering,
what happened?


Glenn
 

Volt and amp meters have the same us with DCC as with AC+DC. If you have a
short the voltage will go low and the amperage will go up.

Volts. If your nominal track voltage is 18 volts and you see it down to 6
volts then you have a short. This will also happen when your load exceeds
the capacity of you power supply. An LED will still be glowing.

Amps. The size of you ammeter should exceed the maximum out put of your
power supply. If you notice the amps are way up there or exceeding your
power supply and you have just a few locos running then you could have a
short.

Glenn


Glenn
 

I have one of these. The buffering in it is lousy. The voltage doesn't stay
the same. It is a 7 digit display. It will read 12V but the remaining digits
beyond the decimal are constantly fluctuating. I finally taped over then so
I only could see 12.0.

Glenn

-----Original Message-----
From: WiringForDCC@yahoogroups.com [mailto:WiringForDCC@yahoogroups.com] On
Behalf Of Mike G
Sent: Wednesday, November 03, 2010 13:10
To: WiringForDCC@yahoogroups.com
Subject: RE: [WiringForDCC] Re: ADAPTING DC METERS TO DCC

Harbor Freight has a digital meter that is on sale from time to time for
less than $3.00. I have used it for voltage measurement on the tracks for
quite some time. It appears that it is "close enough for work" on the 200
VAC scale.



Mike G.


Max Maginness
 

Different meter - the (currently local price) $2.99 one is 4 digits. I made
a plug in diode rectifier + averaging circuit to go with it. Works very well
with the 20VDc setting.



However the input impedance is only 1 megohm compared to 11 megohms for a
"real meter" so not all the published circuits for DCC-DC conversion will
work quite accurately. Main thing is that it does give a consistent reading.
Using the AC range on an inexpensive meter is quite variable depending on
the meter design.



Max



BTW the original thread was on using conventional analog meters - we have
wandered a ways.



From: WiringForDCC@yahoogroups.com [mailto:WiringForDCC@yahoogroups.com] On
Behalf Of Glenn
Sent: Wednesday, November 10, 2010 8:36 AM
To: WiringForDCC@yahoogroups.com
Subject: RE: [WiringForDCC] Re: ADAPTING DC METERS TO DCC





I have one of these. The buffering in it is lousy. The voltage doesn't stay
the same. It is a 7 digit display. It will read 12V but the remaining digits
beyond the decimal are constantly fluctuating. I finally taped over then so
I only could see 12.0.

Glenn

-----Original Message-----
From: WiringForDCC@yahoogroups.com <mailto:WiringForDCC%40yahoogroups.com>
[mailto:WiringForDCC@yahoogroups.com <mailto:WiringForDCC%40yahoogroups.com>
] On
Behalf Of Mike G
Sent: Wednesday, November 03, 2010 13:10
To: WiringForDCC@yahoogroups.com <mailto:WiringForDCC%40yahoogroups.com>
Subject: RE: [WiringForDCC] Re: ADAPTING DC METERS TO DCC

Harbor Freight has a digital meter that is on sale from time to time for
less than $3.00. I have used it for voltage measurement on the tracks for
quite some time. It appears that it is "close enough for work" on the 200
VAC scale.

Mike G.



_____

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Checked by AVG - www.avg.com
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rg <richg_1998@...>
 

We have to specify, analog meter or digital meter.

Rich


Inside every older person is a younger person wondering,
what happened?