The AO55 Transmitter is a blind (non-indicating) 4-20 mA transmitter, designed for use with almost all Seametrics flow sensors. It accepts a pulse frequency input from the flow sensor, and converts this input into a continuous analog output signal. Power for the transmitter is taken from the current loop itself, so only two wires are required. The digital design makes it possible to span the unit in the field without tools. For maximum environmental protection, the electronic components are encased in a special semi-flexible urethane potting material.

The housing is cast from aluminum and fuse-coated. The AO55 will operate on a relatively wide range of current loop voltages, 24 to 36 Vdc. Typical applications for this transmitter are telemetry (or SCADA), distributed control systems, programmable controllers, data logging, and chart recording.