Design On The Seawater CTD Monitor

Ocean has very important strategic position for the national coastal socio-economic development and national security. Our country has long coastline and vast sea, so the research and development for the ocean has great significance. Thermohaline deep-water measurement techniques are one of the key technologies about the research of ocean, namely the CTD (thermohaline deep) measurement technology, which is seawater conductivity, temperature, depth measurements. Through the measurement of these three parameters can grasp the changes in water quality and marine climate change.At present, the monitoring of deep-sea thermohaline main contain shore station observations, buoy observations, ship observations, satellite remote sensing, aerial remote sensing, radar monitoring, etc.. In this paper, a design that is applicable to offshore shore observation station thermohaline deep-water monitor on the coastal waters of long-term observations. The monitoring apparatus contain the host computer monitor (observatory) and the next-bit machine (thermohaline deep sensors). The main host computer are sent orders, receive data, display data, store data, and the next-bit machine is mainly collected seawater temperature, conductivity, pressure parameters. The communication between the PC and the next-bit machine adopt the way of fieldbus. In this paper, Designed an offshore deep water thermohaline monitor which is suit for coastal waters for long-term observation. Monitor consists of two parts: The thermohaline deep-water parameters were measured and the next bit of the parameters of the host computer to monitor the treatment.In this paper, Design parameters of the seawater CTD hardware signal conditioning circuit. Through the single-chip implementation of the CTD parameters collection, designed to simultaneously stress signals and signal conductivity temperature error compensation software algorithms, the preparation of a single-chip procedures, improve measurement accuracy, Designed Modbus protocol based on the RS485 bus communication interface, and the preparation of Modbus Protocol Based on SCM procedures, designed PC users to monitor the software structure, in VC + +6.0 integrated environment prepared PC Modbus Serial Communication Protocol procedures. The use of single-chip simulation software Proteus-bit machine to the next signal acquisition procedures and protocol procedures Modbus hardware simulation and hardware experiment, the experiment was completed through data collection and data transfer to PC. And designed the experiments of the CTD error detection parameters.This article is designed based on the RS485 bus and Modbus protocol next-bit machine data communications, through experiments proved the feasibility of the system, on the coastal region can achieve long-term real-time monitoring.