How to Perfectly Combine Siemens PLC with Real-Time Database

How to Perfectly Combine Siemens PLC with Real-Time Database? Unveiling the Core Technology of High-Speed Data Processing to Support Industrial Big Data Applications!

Hello everyone, I am Hanhan! Today we will discuss the “super combination” in the industrial field— the perfect combination of Siemens PLC and real-time databases. This duo is like the “Superhero Alliance” in a factory, one responsible for on-site control and the other for data processing, working together to create the future of smart factories!

1.

Meet Our Main Characters

Siemens PLC: The “Brain” of the Factory

Siemens PLC is like the “commander” in the factory. It can receive signals from various sensors, such as temperature, pressure, and liquid level, and then make decisions based on pre-set programs to control the operation of various devices. Imagine, the PLC is like a super attentive housekeeper, always keeping an eye on every corner of the factory.

Real-Time Database: The “Delivery Guy” of Data

The real-time database is like a super diligent “delivery guy”. It can collect, store, and process large amounts of data at an astonishing speed. In the industrial site, thousands of data points may be generated every second, and the real-time database is responsible for quickly delivering this data to where it is needed.

2.

How to Achieve the “Marriage” of PLC and Real-Time Database?

1. Choose the Right Communication Protocol

We need to make the PLC and real-time database “speak the same language”. Common protocols include:

• OPC UA: This is the “Mandarin” of industrial communication, supporting cross-platform and cross-system data exchange.
• Modbus TCP: An old-school communication protocol that is simple and easy to use, suitable for small systems.
• S7 Protocol: Siemens’ own protocol, which works best with Siemens PLCs.

Tip: When choosing a protocol, consider system scale, real-time requirements, and future expansion needs.

2. Hardware Connection

PLC and real-time database servers are usually connected via Ethernet. Ensure the network is stable and reliable, preferably using industrial-grade switches and cables.

[PLC] <---> [Industrial Switch] <---> [Real-Time Database Server]

Note: The industrial site environment is complex, so ensure proper network protection and redundancy design.

3. PLC Program Design

In the PLC, we need to create a data block (DB) to store the data to be transmitted. For example:

DATA_BLOCK "ProcessData"
{ S7_Optimized_Access := 'TRUE' }
VERSION := 0.1
NON_RETAIN
VAR
Temperature : Real;   // Temperature
Pressure : Real;      // Pressure
FlowRate : Real;      // Flow Rate
AlarmStatus : Bool;   // Alarm Status
END_VAR
BEGIN
Temperature := 0.0;
Pressure := 0.0;
FlowRate := 0.0;
AlarmStatus := false;
END_DATA_BLOCK

Key Point: Ensure that the address of the data block is fixed for easy reading by the real-time database.

4. Real-Time Database Configuration

Taking a well-known real-time database as an example, the configuration steps are as follows:

1. Create PLC device connection point
2. Configure communication parameters (IP address, port, protocol, etc.)
3. Create tag points corresponding to the variables in the PLC data block
4. Set collection cycle and storage strategy

Tip: You can use the batch import function of the real-time database to quickly create a large number of tag points.

3.

Practical Application Case: Temperature Monitoring System in Steel Plant

Imagine in a steel plant, we need to monitor the temperature of multiple blast furnaces.

The PLC is responsible for collecting data from temperature sensors and controlling the cooling system. The real-time database is responsible for storing historical temperature data and providing real-time trend graphs for operators to view.

[Temperature Sensor] --> [PLC] --> [Real-Time Database] --> [Operator Workstation]
|
v
[Cooling System]

Key Point: The data exchange cycle between the PLC and the real-time database must be fast enough, usually at the millisecond level, to ensure that the cooling system can respond to temperature changes in a timely manner.

4.

Common Problems and Solutions

1. Data Loss

* Reason: Unstable network or high PLC load
* Solution: **Configure caching strategy in the real-time database, automatically retransmit data when the network recovers**

1. Data Desynchronization

* Reason: Inconsistent clocks between PLC and real-time database
* Solution: **Configure NTP server to unify the clocks of all devices in the factory**

1. Slow System Response

* Reason: Too high data collection frequency or too large data volume
* Solution: **Optimize collection strategy, combining change collection and time interval collection**

5.

Practical Suggestions

1. Start with a small system and gradually scale up, accumulating experience.
2. Regularly back up PLC programs and real-time database configurations.
3. Establish a sound data quality monitoring mechanism.
4. Pay attention to network security and regularly update system patches.
5. Develop emergency plans to ensure reliable system operation.

That’s all for today’s sharing. With the skills of combining PLC and real-time databases mastered, I believe everyone has made significant progress on the road to smart manufacturing! Remember to practice more in actual projects, and don’t be afraid of problems; solving problems is the best opportunity to improve your abilities. Next time we will talk about more interesting industrial control technologies, see you next time!