Shipboard Sea Of ​​heavy Metal Elements In The Scene And An Automatic Analyzer System Design

The paper describes hardware and firmware implementations of the analytical instrument used to detect trace heavy metal in seawater. Multiple measurement techniques (chalcogenide ion selective electrode, differential pulse stripping voltammetry, light addressable potential sensor) have been combined to detect nine kinds of heavy metal. The instrument is integrated with a multi-channel high precision open circuit potential measurement system for the ion selective electrode and a potentiostat used in voltammetry, an analog lock-in amplifier is also presented to measure the response of light addressable potential sensor. With the embedded firmware, the instrument can perform the entire analysis automatically, thus provide a perfect solution for fully automatic on-line analysis.We have designed different measurement instruments according to the methods. The instrument used to measure electrode is a high precision multi-channel system constructed with a IAADC as the core and high input impedance amplifier and low input current multiplexer. The Electro-chemical measurement system used to perform DPSV measurement is constructed with two parts, a low-current measurement system consists of low input bias current operational amplifier and a high resolution SAR ADC and a potentialstat consists of high resolution DAC and high current buffer amplifier. The core of the Lock-in amplifier used to measure response of LAPS consists of a high precision modulator/demodulator and DDS as signal generator. A standardized communication protocol is running on all instruments, which is built by ourselves and has the code name of FlexLynx, it provide complex functions like data frame generation, data integrity check and time-out retransmission, so that data maintain its integrity while exchanging between PC and instruments.The instrument features full automatic measurement, wonderful extensibility and high reliability. The prototype has been assembled and fully checked , test results show it's hardware performance can satisfy our project in all aspects.