NK Technologies ADC Series Signal Converter connects up to eight 4-20mA loop-powered analog sensors, or up to eight separately powered 4-20mA output sensors, or up to four of each. This will produce a digital signal representing 0-100% of each sensor output. It is the perfect solution for photovoltaic power production system monitoring. NK Technologies CTC Series Signal Converters allow you to use an existing standard 5A secondary or low-voltage ProteCTâ„¢ current transformer over a conductor to produce an industry standard 4-20mA two-wire, loop powered signal.