AP2-1 Current Loop unit 4–20 mA has been designed to convert digital value of mass to analog value. It is a unit of passive type, i.e. it requires to be supplied with power from an external source, of 24 VDC voltage value.
 
AP2-1 Current Loop unit indicates mass as:

The AP2-1 is intended for cooperation mainly with scales operated via PUE C315 and PUE 7.1 indicators. It is housed in a plastic casing, and powered with power supply 230V/5VDC. The AP2-1 and the power supply are sold as a set. The current circuit is led through 1.7-meter-long cable.