Patent ID: 8395517

Claim:
In a filter monitoring device for detecting variances in pressure of flue flowing through a filter element in a filter assembly, said monitoring device including: (i) a member which is axially movable in response to changes in the differential pressure of the fluid in said filter assembly, the movement of said movable member being detected by a Hall effect sensor which generates voltage based upon the proximity of said movable member to said sensor, (ii) a first indicator means for conveying data of changes in said differential pressure, and (iii) temperature sensing means for measure or detecting any change in temperature of the fluid being filtered and for transmitting data showing any changes in temperature, the improvement comprising: an operational amplifier for receiving data from said first indicator, a microcontroller for receiving data (a) from said operational amplifier and (b) from said temperature sensing means, said microcontroller converting data received from said operational amplifier and said temperature sensing means to digital format, said microcontroller determining an output voltage code for differential pressure based upon voltage from said Hall effect sensor and an output voltage code for temperature based upon actual temperature of fluid flowing through said filter, said microcontroller transmitting said voltage codes along two differential digital lines to a drive and output connector.