External Backup Device for PLC Program Integrity
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Solution Overview
Problem
Programmable controllers, such as those controlling production lines or chemical reactors, lack built-in backup capabilities and means to detect program manipulations or virus contamination, necessitating external devices for data backup and monitoring.
Innovation Solution
A backup device with an interface to connect to the programmable controller, a transmission unit to read/write data, a memory unit for storage, a comparison unit to identify manipulations, and a warning unit to alert operators of changes, ensuring non-manipulated program integrity through cyclic data backups and user confirmation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If no backup means are installed in the programmable controller, then the device complexity is reduced and ease of manufacture is improved, but the reliability is worsened because program data and other stored data cannot be backed up
Solution Approach 1:
The backup functionality is extracted from the programmable controller and implemented as a separate external backup device. This allows the controller to remain simple and easy to manufacture while the backup capability exists in an external unit that interfaces with the controller through standard communication protocols.
Solution Approach 2:
An external backup device serves as an intermediary between the programmable controller and the backup storage medium. This mediator handles all backup operations, program comparisons, and manipulation detections, allowing the controller itself to remain unchanged and simple while gaining enhanced reliability through the external backup system.
2Ease of manufacture
If standard operating systems are not used in the programmable controller, then the device complexity is reduced and ease of manufacture is improved, but the capability to detect program manipulations and virus contamination is worsened
Solution Approach 1:
The virus detection and program manipulation detection capabilities are extracted from the controller's operating system and implemented in the external backup device. The backup device performs cyclic comparisons of program data between the controller and backup storage, detecting manipulations without requiring the controller to have complex detection software.
Solution Approach 2:
The external backup device implements a feedback mechanism by continuously comparing program data in the controller with backed-up versions and generating warnings when manipulations are detected. This provides ongoing security monitoring without adding complexity to the controller's operating system.
3Reliability
If cyclic data backup is implemented, then the reliability is improved by detecting program manipulations, but the loss of time increases due to periodic backup operations
Solution Approach 1:
The backup device performs cyclic backups at predetermined time intervals rather than continuously. This periodic action balances the need for reliable manipulation detection with the need to minimize time loss, as the comparison operations occur only at scheduled intervals rather than constantly.
4Device complexity
If manual backup operations are performed, then the device complexity is reduced, but the productivity is worsened due to operator involvement requirements
Solution Approach 1:
The backup device operates autonomously by automatically connecting to the programmable controller, performing cyclic data backups, comparing program data, detecting manipulations, and generating warnings without requiring operator intervention. This self-service operation maintains simple device architecture while significantly improving productivity by eliminating manual backup tasks.
Data Source
Figure 1
AI summary
The invention discloses a backup device (100), adapted to conduct a backup of a control device (200), with - an interface (104), which may be coupled with the control device (200); - a transmission unit (102), adapted to read data from the control device (200) via the interface (104) and/or write data to the control device (200) via the interface (104); - a memory unit (108, 116), adapted to store the data read from the control device (104); - a backup control unit (102) adapted to instruct the transmission unit (102), to read at least part of a program memory (208) of the control device (200) as first program backup data (120), and to instruct the memory unit (108, 116) to store the first program backup data (120) in a non-volatile way, wherein the backup control unit (102) is further adapted to instruct the transmission unit (202) to read at least part of a program memory (208) of the control device (200) as further program backup data (122, 122a); - a comparison unit (102) adapted to compare the first program backup data (120) and the further program backup data (122, 122a); and - a warning unit (102) adapted to release a warning, if the comparison unit (102) determines that the first program backup data (120) and the further program backup data (122, 122a) differ.