This technical requirement clarifies the data transmission communication method and communication process between the surface water quality automatic monitoring station and the data monitoring operation and maintenance management platform, formulates the technical implementation method of the remote platform and on-site interactive communication, and defines and regulates related terms The definition and information coding are applicable to the communication requirements of data interaction and remote control on the spot and the corresponding data monitoring operation and maintenance management platform of the surface water automatic monitoring station of fixed type, simple type, small type, fixed platform of water station and floating ship type.
Technical requirements cited documents: "HJ 212-2017 pollutant online monitoring (monitoring) system data transmission standard", "GB / T 19582-2008 Modbus protocol-based industrial automation network specifications", "HJ 525-2009 water pollutant name code ".
Data acquisition and transmission instrument
SCM, industrial computer, embedded computer, programmable automation controller (PLC) or programmable controller that collect data of various types of monitoring instruments, complete data storage and data transmission and communication with the host computer, hereinafter referred to as digital mining Instrument or base station.
It is a data receiving and data processing system installed in environmental protection departments at all levels, connected to a data acquisition instrument through a transmission network and issuing instructions such as query and control, including computers and computer software. This technical requirement is referred to as a host computer.
Composition method of surface water online monitoring system
There is one or more sets of monitoring instruments on site. The monitoring instruments have a digital output interface and are connected to an independent data acquisition and transmission instrument. The host computer communicates with the field machine through the transmission network (including initiation, data exchange, and response)
Data is transmitted between the field machine and the host computer based on the computer network, and the specific networking mode is not limited.
The data transmission protocol specified in this technical requirement is applied to the application layer of TCP / IP, that is, when communicating between the field machine and the host computer,
The content and specifications of the exchanged messages, at the TCP / IP transport layer, specify the use of the TCP protocol.
The complete command consists of the requester's initiation and the responder's response. The specific steps are as follows:
1) The requester sends a request command to the responder;
2) After receiving the request, the responder sends a response to the requester (handshake completed);
3) After the requester receives the request response, wait for the responder to respond to the execution result; if the requester does not receive the request response, press the request back
Should be processed overtime;
4) The responder performs the requested operation;
5) The responder sends the execution result to the requester;
6) The requester receives the execution result and the command is completed; if the requester does not receive the execution result, it is processed according to the execution timeout.