Abstract: Flow meters are extremely important in industry. There are many types of flow meters. One of them is one based on Hall effect whose output is modulated square wave which is difficult if not impossible to be caught by most the digital controllers such as DCS, PLC and alike. This paper presents an electronic interface which addresses this problem where it could solve any analog interface almost to any digital controller. The design first signal conditioned the output of the Hall effect sensor, then converts it into voltage which is also signal conditioned to limit the output in the range of 0-5V for 55-550Hz input (1-10L/min). This signal is then converted to 4-20mA current which could easily be read by any digital controller such as PLC, DCS, RTU.