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At present, domestic and foreign manufacturers mainly have two schemes for industrial IoT data collection [6] measures.
One is to use the embedded industrial gateway to access the industrial site, or through the Ethernet, or through the serial port, or through the OPC (OLE for Process Control) server and other media for data collection. This method requires the purchase of hardware equipment from the manufacturer, which is often expensive, and is strongly bound with the equipment manufacturer’s platform, which is not conducive to user development and difficult to meet the needs of individualization and customization. The advantage is that for customers who do not require much, it is easy to use and does not need to consider a lot, and the after-sales service is relatively guaranteed.
The second is to use the data transmission unit DTU (Data Terminal Unit) for transparent transmission, connect field devices to the manufacturer's cloud, and realize data collection through Socket. This method does not need to purchase or replace the manufacturer's hardware gateway, and can directly use the user's existing equipment, reducing hardware cost overhead. The disadvantage is that the price of cloud services depends on the manufacturer, the user's voice is weakened, and the migration of data is restricted.
Needs and solutions
data collection
The system is required to support the communication protocol of the user equipment. The following two protocols can meet the basic needs of users:
- Modbus TCP
In order to support some primitive serial port protocols, Modbus RTU also adds support for the DTU transparent transmission module; in
order to facilitate the user's operation and configuration, the system configuration file must be clear and clear, and the JSON format is selected here .
system design
Development language: Go;
data collection protocol: Modbus;
configuration file distribution and data storage scheme: MQTT;
time series database: InfluxDB, OpenTSDB;
configuration file and API: JSON;
overall deployment and installation: Docker;
overall framework:
- Main function module
- Acquisition drive module
- Storage driver module
Main function module
Acquisition drive module
Storage driver module
Conceptual understanding
Modbus protocol
The Modbus protocol is the world's earliest bus protocol used in industrial fields. Many industrial equipment, including PLCs, DCS, smart meters, etc., use this protocol as the communication standard between them; in
simple terms, it is the most widely used communication in the industry. Protocol, there are several variants on this basis;
Modbus protocol analysis-a protocol that Xiaobai can understand at a glance
RS-232
It is a kind of serial communication, learned in the class of microcomputer principle;
reliable transmission method of RS232 interface
PLC (Programmable Logic Controller)
Basic knowledge
HINET Smart Gateway
There are special equipment that can realize PLC remote programming and other functions:
Huachen Zhitong-HINET intelligent gateway product parameters and basic functional characteristics
Realize PLC remote monitoring by way of mobile phone APP