I need a signal transformer Input; -50mV - 50mV OR -100mV - 100mV And then the output 4-20mA the circuit has to balance so that -50/-100mV = 4mA 0mV = 12mA 50/100mV = 20mA If Anyone knows where to get one, link it, or if anyone knows how to make it, please make me a schem. The whole lot is to be used as a curent measuring device for 24V DC, so if anyone knows of a unit that you put -100 to +100 Amps of DC thru it, and it sends out 4-20mA it can also be used... Thanks for the help..
A transformer won't work for DC, the way they work they will only work with AC, you can use a shunt, a high wattage, low resistance resistor, or possibly some more advanced Hall effect meters. I wouldn't even try to make my own Hall effect meter though, they are hard enough to just buy the meter as a whole, le alone make your own. If you can find a say, .01 Ohm resistor with a tolerance >.5%, you could measure the voltage across the resistor, .01V per amp, so at 100A you would get a 1v difference. The problem would be finding the shunt though. Oh and for units, you just want A, not mV, mV is millivolts, 1/1000 of a volt.
I dont need it anymore, I found another instrument that have a 50mV input Anyways, a normal DC-shunt (resistor) outputs mV ex.; 100A/50mV 50A/65mV 100A/100mv and the instrument i had was designed for the industrial standard, 4-20mA. The inwtrument I had, and the instrument i bought are these; http://store.datel.com/cgi-bin/datel.storefront/EN/Catalog/1013 I also ordered a blue version oh, and "doomy" i know, sorry for using wrong word to explane, I shoud have wrote "signal converter" just my brain using the wrong translation for "omformer" (Norwegian)
