The SCOUNT board is a circuit board used with the ODAS (Ocean Data Acquisition System) to sample data from channels that have a frequency output. The usual application is to read the frequency produced by a SeaBird SBE3/4 Thermometer/Conductivity probe. These devices, and some propeller current meters, output an AC-coupled square wave with a frequency that is a precision function of the measured parameter (temperature, electrical conductivity of seawater and current speed).
The function of the SCOUNT board is to turn these frequency signals into 32-bit numbers representing the period of the signal. The high (most significant) byte-pair of these numbers is assigned to an odd-channel address while the low (least significant) byte-pair is assigned to the next even address below the address of the high byte-pair.
The SCOUNT board can handle signals of three different types, namely:
- AC-coupled, or zero-mean, sine, triangle and square waves with amplitudes greater than 0.2 volts.
- Logic-level signals with “high” levels larger than 2.0 volts.
- Fully differential signals with amplitudes greater than 0.2 volts.