ANB Sensors Analogue Signal Unit, 1250 m submersible

The submersible converter sits on the cable between the AQ2 sensor and the logger or control system and turns the sensor's digital output into an analogue signal. It is rated to 1250 m and comes in two versions: the ACU gives a 4 to 20 mA current signal and the AVU a 0 to 5 V voltage signal.

The signal spans pH 2 to 10, so 10.3 mA reads as pH 5.15 and 2.8 V as pH 4.48. The converter needs a power supply and connects to the analogue input of a telemetry unit or logger. It is terminated with a SubConn connector or a pigtail.

Its RS-232 line is used to check and update firmware. The sensor starts measuring on a command from anb_utils, or by itself on a programmed schedule when power comes on.