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Version: 5.6

Basic Concepts

This chapter explains the basic concepts required to understand and implement the architectural recommendations for the OPC Router. It provides an introduction to the key topics that are covered in detail later in the manual.

The OPC Router as a Central Platform​

The OPC Router is a central platform that enables communication between different industrial systems and devices. Its ability to seamlessly transfer and process data makes it a crucial component in the modern Industry 4.0 landscape. The platform supports many different protocols and standards, ensuring a high degree of flexibility and interoperability.

Key functions of the OPC Router​

  • Protocol support: Support for OPC UA, MQTT, REST, databases, SAP, and many other protocols.
  • Data integration: Integration of data from various sources such as PLCs, databases, IoT devices, and cloud services.
  • Visualization and monitoring: Real-time monitoring and visualization of data streams and connections.
  • Automation: Automation of processes through rule- and event-based workflows.

Basics of scalability: vertical and horizontal​

When operating the OPC Router, both vertical and horizontal scaling play a crucial role in meeting the requirements of different company sizes. Here is a more detailed look at both scaling approaches in the specific context of OPC Router operation.

Vertical Scaling​

Definition: Vertical scaling (scale-up) refers to increasing the capacity of a single server or instance by adding more resources such as CPU capacity, RAM, or memory.

Use cases: Vertical scaling is particularly suitable for smaller installations or scenarios where higher performance per instance is required. This could be the case if a single OPC Router processes many data points or performs complex data processing tasks.

Advantages of vertical scaling​

  • Easy implementation: Does not require any changes to the existing application architecture.
  • Low complexity: Since only one instance needs to be managed, administration and configuration are easier.
  • Immediate performance boost: Adding resources can improve performance immediately.

Challenges of vertical scaling​

  • Limited scalability: The capacity of a single server has physical limits.
  • Single point of failure: If the one instance fails, it leads to downtime.

Example: A medium-sized company operates a production hall with an OPC router that collects data from all machines. By adding more RAM and CPU capacity, the processing speed and the amount of data that can be processed can be increased without the need for an additional instance.

Horizontal scaling​

Definition​

Horizontal scaling (scale-out) means adding additional servers or instances to distribute the load and increase capacity.

Use cases​

Use cases: Ideal for larger installations or scenarios where high availability and load balancing are required. Horizontal scaling is particularly useful in large production environments or distributed locations.

Advantages of horizontal scaling​

  • Virtually unlimited scalability: Capacity can be expanded almost indefinitely by adding more instances.
  • Improved fault tolerance: Redundancy allows individual instances to fail without affecting the overall system. This minimizes downtime.
  • Flexibility: New instances can be easily added or removed to respond to changing requirements.

Challenges of horizontal scaling​

  • Increased administrative overhead: Multiple instances must be managed and monitored.

Example: A large company operates multiple production halls and locations. By setting up multiple OPC Router instances for each production hall or location, data processing can be performed locally, distributing the load and increasing system reliability. Additional instances can be added as needed to expand capacity.

Practical implementation​

Vertical scaling​

  1. Resource analysis: Determine current resource requirements and identify bottlenecks.
  2. Upgrade: Add additional CPU capacity, RAM, or storage to the existing OPC Router instance.
  3. Monitoring: Monitor performance after the upgrade to ensure that the expected improvements are achieved.

Horizontal Scaling​

  1. Demand Analysis: Analyze the load and identify areas that would benefit from additional instances.
  2. Instance Provisioning: Set up additional OPC Router instances, configure them, and connect them to the existing network.
  3. Load distribution: Export the project components that are to be transferred to the additional instances from the existing OPC Router instance.
  4. Commissioning: Import the exported project components into the new instances and deactivate the connections in the original instance. Switch the new instances to productive mode and verify that the new instances have been successfully integrated.
  5. Monitoring and maintenance: Monitor the performance of all instances and perform regular maintenance.

This refers to multiple instances. However, a single instance can also be added according to these steps in order to scale horizontally.

Separation of Concerns in OPC Router​

Definition and significance of SoC​

Separation of Concerns (SoC) is an architectural principle that aims to clearly separate different responsibilities and areas of responsibility within a system. This leads to a clearer structure and more efficient operation of the systems.

In the context of the OPC Router, this means that the various "concerns" or responsibilities within an OPC Router instance are identified, summarized, and then distributed across multiple instances so that there are no dependencies. This greatly facilitates expansion and scaling.

Application of SoC in the OPC Router​

Modularization of "concerns"​

  • Individual instances for different responsibilities: In an OPC Router architecture, different responsibilities, such as connecting different production areas or plants, should be grouped together in separate instances. This means that each instance of the OPC Router is responsible for a specific task or area.
  • Example: One instance could be responsible for communicating with the machines in Hall A, while another instance processes the data from Hall B.

Advantages of separating the "concerns"​

  • Simpler extensions: When introducing a new plant, hall, or location, another OPC Router instance with the same or similar configuration can simply be added. This reduces the effort and complexity involved in expanding the system.
  • Scalability: The clear separation of responsibilities allows the individual instances to be scaled independently of each other. If requirements in one area increase, the corresponding instance can be expanded in a targeted manner. This can be done by adding more hardware resources for the instance. Alternatively, horizontal scaling can be performed by adding additional instances.
  • Independent updates: Security, software, and configuration updates can be performed more easily and in a more targeted manner. Since the instances are separate from each other, updates can be performed without affecting multiple production departments or processes at the same time.
  • Error isolation: Problems in one instance (e.g., hardware errors or software crashes) do not affect the other instances. This increases the overall stability and reliability of the system.

Practical implementation​

Setting up separate instances​

  • Planning: Start by planning which areas or tasks should be separated. Identify the main responsibilities and distribute them across separate instances.
  • Implementation: Set up the instances of the OPC router according to the planned distribution. Ensure that each instance has the necessary connections and configurations to perform its specific tasks.
  • Maintenance and monitoring: Monitor the instances regularly and perform necessary maintenance work. Use the separation of instances to make targeted updates and improvements.

Example of an architecture​

  • Instance 1: Responsible for machine control and data acquisition in Hall A.
  • Instance 2: Responsible for quality control and warehouse management in Hall B.
  • Instance 3: Responsible for energy monitoring and environmental controls throughout the plant.

Summary​

Understanding the basic concepts of vertical and horizontal scaling, as well as the principle of separation of concerns, is crucial for the successful implementation and use of the OPC router in companies of various sizes. While vertical scaling offers a simple solution for smaller use cases, horizontal scaling enables virtually unlimited expansion possibilities and greater reliability. Separation of concerns helps to reduce complexity and increase the efficiency of the system. The following chapters will explore these concepts in greater depth and present practical application examples.