Factory Control Data Publishing Based on Receiver State
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Solution Overview
Problem
Existing factory automation communication systems, such as those using programmable controllers, face reliability issues due to cyclic communication methods that do not verify whether receiving controllers are connected, leading to potential data loss.
Innovation Solution
A publish/subscribe-type communication system where control devices in a network include a publisher unit and a subscriber unit, with the publisher transmitting data only when the state of receiving control devices satisfies a predetermined reception allowing condition, ensuring reliable data transfer even without established connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cyclic communication is used without checking receiver availability, then communication simplicity is maintained, but data reception reliability deteriorates
Solution Approach 1:
The system performs preliminary actions by having the subscriber unit transmit a state indicating whether it can receive data before the publisher unit sends control data. This advance information allows the publisher to determine whether transmission will be successful, preventing data loss without requiring complex real-time connection verification.
Solution Approach 2:
The subscriber unit provides feedback about its data reception capability by transmitting its state to the publisher unit. This feedback mechanism enables the publisher to make informed decisions about whether to transmit data, thereby improving reception reliability while maintaining the simplicity of the publish/subscribe communication model.
2Reliability
If connection establishment is required before data transmission, then data reception reliability is improved, but communication complexity increases
Solution Approach 1:
Instead of requiring full connection establishment procedures, the system uses a simplified approach where the subscriber unit transmits its state information. This partial action provides sufficient information for reliable data transmission decisions without implementing the complete complexity of traditional connection establishment protocols.
Data Source
AI summary
Reliability with which a control device at a transmission destination can receive data is improved. In a communication system in which a plurality of control devices for factory automation are connected to a network, a communication protocol among the control devices includes a publish/subscribe type. Each of the control devices includes: a data storage unit in which control data is stored; a publisher unit that transmits data including a state of the control device of the publisher unit itself to other control devices than the control device; and a subscriber unit that receives data from each of the other control devices. When a state of each of the other control devices that is received by the subscriber unit satisfies a reception allowing condition, the publisher unit transmits the control data of the control device of the publisher unit itself.