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| Electronic Projects Design/Ideas/Reviews Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our experienced members find a solution. |
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Thread Tools | Display Modes |
28th March 2003, 03:35 AM
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Digital Panel Meter Interface
I am building a power supply (16v 6.6a) and would like to monitor amperage output
I have tried using resistance wire on the ground side (return to supply), Measuring voltage drop across it. This works but I don't think this is the best way to do it. So I got a current sensing shunt resistor (.1ohm 5watt) its good for 15A I like this but, my amperage reading on the digital meter is off by.05A how do I adjust the circuit to compansate for the error. Or do I need a different value shunt resistor. I am a newbie to electronics, Please help. Mark |
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28th March 2003, 06:57 AM
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What is the panel meter sensitivity? 200mV?
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28th March 2003, 02:16 PM
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It is configurable for 200mv, 2v, 20v, 200v, 500v ac or dc and also
milliamps - 200ma I have it set for 2v, this gives me the range I need, ie allows me to read over 2.0a The panel meter is a pm128e from circuit specialists http://www.web-tronics.com/panelmeter.html Mark |
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28th March 2003, 07:23 PM
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The value of your series resistor can be calculated from :
the fsd of your meter, currently set to 2v the max load current, e.g 6 amps. from Ohms law we get R=V/I so, 2/6 =0.33333 Ohms and the power rating from V*I or 2*6 = 12 watts....... Get the drift ? BTW there's nothing wrong with using a series resistor in the neg or pos line, but try and make it as low as poss to minimise volt drop and dissipation |
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28th March 2003, 10:28 PM
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Sorry but I am confused.
The shunt resistor that I am using is good for 15A http://www.precisionresistor.com/PLV5.htm it is a 5w .1a 1%, Current sensing shunt resistor My actual amp reading is off by .05a. I would like to adjust it so it is correct. I am unsure on how to do this. This is my question. I am a newbie to electonics, self learning, It is easy to talk over my head. Any ideas on how to adjust the circuit.??. Do I need a .01a shunt resistor Mark [/url] |
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28th March 2003, 11:09 PM
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Configure the pnelmeter to 200mV, and apply 0.01 ohm shunt resistor. If the panelmeter is 3,5digit (unfortunately the link is dead), the max. readout is 19.99A.
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28th March 2003, 11:26 PM
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Sebi,
So I got the wrong shunt resistor, I will try one that is .01a. I have to order it, when I get it I will post the results. Is there any way to adjust the exsisting circuit so it reads correct, Still using the .1a shunt resistor. The links work I just cked them Thanks Sebi. Mark |
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29th March 2003, 08:16 AM
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Yes, in 200mV range You can calibrate it with other multimeter.
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Linear Mode
