I was just taking a wander through RS and found something called a Current Transducer. AFAICS you get to measure the current without interfering with the circuit and translate this into a voltage level. Now when I get my monitoring setup I will have plenty of scope for voltage readings if these devices convert a current reading to a voltage level I can work out the power consumption. Now this isn't exactly essential, but I rather fancied the idea of knowing the power consumption of the PSU and maybe the pump. I'm working on a project to have lots of temp readings, flow rates etc and this would fit in well. Anyway what are the issues with these things and/or what to I need to know? I can see how they work in theory, but wouldn't know what concerns or side effects there would be in practice. Thanks in advance, as ever.........
I'm pretty sure DC Current Transducers don't exist, you could mesure the current on the wire leading into the PSU from the wall outlet, but anything else isn't going to work i'm afraid.
For the PSU, I guess I'd be looking at the AC imput current as there are too many output lines. However all the ones I saw on RS, said All of the ones at RS seemed to be from http://www.lem.com and there was a vast (confusing) range. If you're curious they shopw up at http:www.rswww.com under All Products | Automation | Sensors/Transducers | Current Sensors | Current Transducers , alas its hopeless to try and link to them.
The AC ones are fairly simple, bit like transformer principle. IIRC the DC ones use hall-effect technology.
Yes they do. These can also measure AC as well. As for your question Risky, Can you give a part # or a link right to the part itself so I can see exactly what it is you're dealing with?
Well the catch is that there's a huge range, but taking a stab in the dark I get: LEM Part Number LTS 6-NP R S Code 4362320 After a fight I found a datasheet http://www.ntb.ch/Pubs/sensordemo/pdf_data/LTS_6_NP_Lemstromwandler.pdf Alas you can't link to docs at www.rswww.com or www.lem.com but serarch RS for current transducers and you get the whole range.
Based on the data sheet you posted, this will do what you want with no side effects. This current to voltage transducer can measure AC and DC up to 6A. Theres even a hole in it to feed a wire through so you don't have to cut your wire and solder onto the pins. But a few things before you run out to buy one... You say you want to know the power consumption of your psu, are you measuring the incoming AC line or are you wanting to measure the DC rail outputs? Either way the 6A this transducer is designed for seems a bit low, but remember, the bigger you go the worse your resolution gets. Anyway give me a better idea of exactly what it is you're trying to do so I can help you further.
Well my first thought was to try and measure the AC input current to the PSU, thus being able to work out the total power consumption of the system. Thus 6A is probably excessive as say a 420W PSU at 75% efficiency would be um, 2.3A I suppose. The other use would be the DC supply to a pump I'm getting that would be c 1A@24VDC . Of course this all requires me to get my planned A/D reading bits in place, but it seems a promising option.
