thecapitalizt Posted October 6, 2004 Report Share Posted October 6, 2004 Okay, here goes. I'm the head of IT for the fuel cell car project at our school (you can see our work at the site that I run for it: DHS Fuel Cell Project). The software supplied w/ the fuel cell itself was created in Labview, however it was packaged in an executable, so I can't add my own modules into it. For the second phase of the project, I intend to design and implement a digital dashboard, with all of the variables and vital statistics that the driver needs to know about. Since the software that came with the fuel cell was Labview, I decided to go with that. In the past week, the electrical engineering group has decided to implement a hybrid power system, with the fuel cell charging the battery for an extra push. Although the fuel cell has voltage and amperage draw sensors on board, they only sense the current that its generating. I need to monitor the current being drawn from the battery bank and input it into labview, however I can't seem to find the sensors that I need. Because of size/cost concerns, we're going with the $415 USB interface with 4 analog inputs, and I would like to know what sensors I would need to use with that. Anyone's help will be GREATLY appreciated. Quote Link to comment
JohnRH Posted October 6, 2004 Report Share Posted October 6, 2004 Okay, here goes.I'm the head of IT for the fuel cell car project at our school (you can see our work at the site that I run for it: DHS Fuel Cell Project). The software supplied w/ the fuel cell itself was created in Labview, however it was packaged in an executable, so I can't add my own modules into it. For the second phase of the project, I intend to design and implement a digital dashboard, with all of the variables and vital statistics that the driver needs to know about. Since the software that came with the fuel cell was Labview, I decided to go with that. In the past week, the electrical engineering group has decided to implement a hybrid power system, with the fuel cell charging the battery for an extra push. Although the fuel cell has voltage and amperage draw sensors on board, they only sense the current that its generating. I need to monitor the current being drawn from the battery bank and input it into labview, however I can't seem to find the sensors that I need. Because of size/cost concerns, we're going with the $415 USB interface with 4 analog inputs, and I would like to know what sensors I would need to use with that. Anyone's help will be GREATLY appreciated. 2139[/snapback] Sorry to answer your question with more questions, but how accurate do your current readings have to be, and what is the range? (are we talking milli-amps or tens of amps?) Also, are you willing to custom design and calibrate something, or does it need to be an 'off the shelf' solution? I am assuming you are talking about DC current? I am also assuming the analog inputs are voltage, and they are a fixed range such as +/-10V, and something cheap like 12bit? The reason I ask all this is because there are a LOT of options here. It would help to narrow it down a little. John Quote Link to comment
thecapitalizt Posted October 7, 2004 Author Report Share Posted October 7, 2004 Yeah, its a DC Current i've got to measure. The fuel cell will output 1200 watts of DC current, and it will max out at 50 amps at 24 volts. I don't need anything precise, just something that will say 'hey, you're at 49 amps. slow down!'. It'll have to be an off-the-shelf solution, b/c i need to have someone to complain to when it doesn't work. I'm using the USB 4-analog input (I think 12-bit), since thats what we can afford at this point Quote Link to comment
Michael Aivaliotis Posted October 7, 2004 Report Share Posted October 7, 2004 Well, all you would need is a current shunt. These little babies can handle up to 50 amps but you could get others that handle higher current. A quick google gave this: http://www.solar-electric.com/mka-100-100.html As you can see, all you need to do is measure voltage across the terminals (good old ohms law). The voltage range is up to 100mA and you need to set your gain accordingly. Quote Link to comment
didierj Posted October 7, 2004 Report Share Posted October 7, 2004 The voltage range is up to 100mA Ohms law seems to be still quite difficult... Think you meant 50mV for the 50 amps and this shunt. Quote Link to comment
Michael Aivaliotis Posted October 7, 2004 Report Share Posted October 7, 2004 Ohms law seems to be still quite difficult... Think you meant 50mV for the 50 amps and this shunt. 2151[/snapback] Well, I wasn't thinking really. I was just reading the specs for the 100Amp version. Quote Link to comment
thecapitalizt Posted October 7, 2004 Author Report Share Posted October 7, 2004 oh I know about the shunt. We use one for the ammeter on the panel we have now. My question is what I would use to measure the flow accross the shunt and get that info into labview Quote Link to comment
Michael Aivaliotis Posted October 7, 2004 Report Share Posted October 7, 2004 As you can see, all you need to do is measure voltage across the terminals... 2143[/snapback] I thought I explained that?oh I know about the shunt. We use one for the ammeter on the panel we have now. My question is what I would use to measure the flow accross the shunt and get that info into labview2158[/snapback] I thought you already said that you have some hardware to do this:I'm using the USB 4-analog input (I think 12-bit), since thats what we can afford at this point... Take the 2 wires from your analog input and put it across the shunt. . Quote Link to comment
thecapitalizt Posted October 7, 2004 Author Report Share Posted October 7, 2004 thanks, I'll try that when the order comes in. Quote Link to comment
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