RDP Virtual Channel Access for PLC Programming in Virtual Machines

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Solution Overview

Problem

In industrial automation, establishing multi-channel communication between a programming device and a virtual machine is complex due to strict security requirements in networks, especially when using public networks like the Internet, as traditional methods require manual setup and often fail to activate necessary virtual channels.

Innovation Solution

Utilizing the Remote Desktop Protocol (RDP) to establish a virtual channel for communication, allowing the programming device to access industrial controllers as if the connection were local, thereby avoiding the need for additional port openings in firewalls and automatic setup of return channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional multi-channel communication methods are used between programming device and virtual machine, then communication functionality is achieved, but setup complexity increases and security requirements become harder to meet

Engineering Contradiction:
Improveconnection setup processVSAvoidcommunication channel configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple communication channels (RDP channel and virtual channel) into a single integrated connection. Instead of establishing separate connections for remote desktop access and industrial controller communication, the invention merges these channels so that both communication needs are satisfied through one unified connection between the programming device and virtual machine, eliminating the need for complex multi-channel setup.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The RDP connection is enhanced to serve multiple functions simultaneously. It not only provides remote desktop access but also establishes virtual channels that enable industrial controller communication. This multi-functional approach allows a single connection type to handle diverse communication requirements, simplifying the overall connection architecture while maintaining security.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple separate connections are established for remote desktop and industrial controller access, then communication functionality is achieved, but the number of connections increases

Engineering Contradiction:
Improvecommunication capabilityVSAvoidnumber of connections
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges remote desktop access and industrial controller communication into a single RDP connection with multiple virtual channels. Instead of requiring one connection for RDP access and separate connections for each industrial controller interface, the invention combines these needs into one unified connection that handles multiple communication tasks simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

While reducing the number of external connections, the patent segments the single connection into multiple virtual channels internally. This segmentation allows different types of data traffic (desktop display, keyboard input, industrial controller communication) to be separated and handled appropriately within the unified connection framework, maintaining adaptability while reducing complexity.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If firewalls and security mechanisms are configured to allow multiple connection types, then communication functionality is achieved, but security configuration becomes more difficult

Engineering Contradiction:
Improvenetwork configurationVSAvoidsecurity setting stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention uses the RDP protocol as a universal access mechanism that handles multiple communication needs through a single connection type. Since firewalls and security mechanisms are typically configured to allow RDP connections, this approach leverages existing security configurations rather than requiring additional complex rules for different connection types, thereby maintaining both ease of operation and security reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3418833B1Method and assembly for enabling access from a first computer to a virtual machine of a second computer
Publication Date: 2021.04.07 SIEMENS AG
  • EP3418833B1 patent drawingFigure 1
  • EP3418833B1 patent drawingFigure 2

AI summary

Method and arrangement for a programming device (PG) of an industrial automation arrangement to access at least one application installed on a virtual machine (VM) of a computer via a network connection, wherein the programming device (PG) is connected to at least one industrial controller (PLC), wherein the application accesses the industrial controller (PLC) by means of the programming device (PG) and by means of an interface connection, and wherein in a first step a remote desktop protocol (RDP-C) connection is established from the programming device (PG) to the virtual machine (VM).In a second step, the virtual machine (VM) establishes a communication link (RDP-VC) between the programming device (PG) and the industrial controller (PLC) via a virtual channel (RDP-VC) of the Remote Desktop Protocol (RDP-C) connection. This provides the application with at least one local communication link. From the user's perspective, only a single connection to the virtual machine (VM) needs to be established using the Remote Desktop Protocol (RDP-C). The necessary return channels can be established automatically, and no security settings in firewalls or routers need to be changed.