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Discussion Boards => General Discussion => Topic started by: Jhanecker2 on February 24, 2017, 10:17:41 AM



Title: DCC Multi-meters ;
Post by: Jhanecker2 on February 24, 2017, 10:17:41 AM
Does anyone  make  a multi-meter capable of reading  DCC electrical  information  directly  ?  John2. 


Title: Re: DCC Multi-meters ;
Post by: Len on February 24, 2017, 11:05:07 AM
You either need a True RMS Multimeter ($350.00+) or one of these things:
http://www.traintekllc.com/rrampmeter-v1-digital-meter-for-dcc-dc-ac-3-rail/?gclid=CJPy-aD_qNICFUEvgQods6MJ-A (http://www.traintekllc.com/rrampmeter-v1-digital-meter-for-dcc-dc-ac-3-rail/?gclid=CJPy-aD_qNICFUEvgQods6MJ-A)

You can use a regular multimeter set for AC, but it will read voltage slightly low because of the squarewave nature of the DCC signal. For general purposes, just check the voltage near the feeder closest to your base station. Use that as a base line when checking for voltage drops around the layout.

Len


Title: Re: DCC Multi-meters ;
Post by: dutchbuilder on February 24, 2017, 05:58:23 PM
Or an oscilloscope. (scope) but that is for experienced users.

Ton


Title: Re: DCC Multi-meters ;
Post by: Hunt on February 25, 2017, 03:57:17 PM
You either need a True RMS Multimeter ($350.00+) or one of these things:
http://www.traintekllc.com/rrampmeter-v1-digital-meter-for-dcc-dc-ac-3-rail/?gclid=CJPy-aD_qNICFUEvgQods6MJ-A (http://www.traintekllc.com/rrampmeter-v1-digital-meter-for-dcc-dc-ac-3-rail/?gclid=CJPy-aD_qNICFUEvgQods6MJ-A)

You can use a regular multimeter set for AC, but it will read voltage slightly low because of the squarewave nature of the DCC signal. For general purposes, just check the voltage near the feeder closest to your base station. Use that as a base line when checking for voltage drops around the layout.

Len




A regular multimeter set for AC will read DCC voltage about 7-10% higher than it is because of the PWM square waveform of DCC.



Title: Re: DCC Multi-meters ;
Post by: Hunt on February 26, 2017, 04:20:30 PM


A regular multimeter set for AC will read DCC voltage about 7-10% higher than it is because of the PWM square waveform of DCC.



Clarification

A regular inexpensive (non RMS) multimeter set for AC may read DCC voltage about 7-10% higher than a true RMS multimeter. True RMS multimeter will read the DCC voltage lower than it actually is.



Model railroad use I use a Harbor Freight CEN-TECH 7 Function Multi-Tester far more than I use my Extech 430 true RMS multimeter. The CEN-TECH was free with coupon. (I have several of them)


 



Title: Re: DCC Multi-meters ;
Post by: Hunt on February 26, 2017, 04:58:45 PM
Off topic ---
Not generally known  ----  the inexpensive Harbor Freight CEN-TECH 7 Function Multi-Tester Item 90899 can be user calibrated. Online videos demo the procedure.