Sea-Bird Electronics SBE 38 Bedienungsanleitung PDF herunterladen (Seite 51)

Appendix I: Functional Description SBE 45

Appendix I: Functional Description

Sensors

The MicroTSG embodies the same sensor elements (3-electrode, 2-terminal,

borosilicate glass cell, and pressure-protected thermistor) previously employed

in Sea-Bird’s modular SBE 3 and SBE 4 sensors, in the SEACAT and

SEACAT plus family, and in the SBE 37 MicroCAT family.

Sensor Interface

Temperature is acquired by applying an AC excitation to a hermetically-sealed

VISHAY reference resistor and an ultra-stable aged thermistor with a drift rate

of less than 0.002 °C per year. A 24-bit A/D converter digitizes the outputs of

the reference resistor and thermistor. AC excitation and ratiometric

comparison using a common processing channel avoids errors caused by

parasitic thermocouples, offset voltages, leakage currents, and reference errors.

Conductivity is acquired using an ultra-precision Wein Bridge oscillator to

generate a frequency output in response to changes in conductivity. A high

stability TCXO reference crystal with a drift rate of less than 2 ppm/year is

used to count the frequency from the Wein Bridge oscillator.

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 103 104

Keine Kommentare

Sea-Bird Electronics SBE 38 Bedienungsanleitung Seite 51