The Model 1530 is a microprocessor based, pressure and temperature compensated, mass flow rate indicator/totalizer. A 4-20 mA output that is proportional to the compensated flow rate and RS-485 communications interface with chart industrial recorders, Suppliers of plcs, and industrial computers. The 16-character display provides one touch indication of compensated flow rate/total, pressure, or temperature. The Model 1530 has two control inputs, which when switched to ground, perform specific functions such as resetting the totalizer. Four open collector control outputs may be used to interface with remote devices such as relays, counters, and lights.