Profinet Frame Aggregation for Field Device Data Transmission
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Solution Overview
Problem
The existing Profinet protocol for data transmission between control devices and field devices in automation technology results in inefficient data transfer due to a low payload-to-fill data ratio, leading to low transmission rates and high cycle times, especially when dealing with small data payloads, and limits the number of active subscribers due to bandwidth constraints.
Innovation Solution
The method involves transmitting data from a control device to multiple field devices and vice versa within a single Profinet frame subdivided into data fields, reducing the need for fill bytes and enhancing transmission efficiency by allowing data to be written directly into assigned fields, thereby increasing the transmission speed and supporting real-time operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If separate Ethernet packets are transmitted for each field device, then data can be transmitted to multiple field devices, but the transmission rate is low due to small payload-to-fill data ratio
Solution Approach 1:
The patent merges multiple separate Ethernet packets into a single aggregated Ethernet packet containing a Profinet frame with multiple data fields. Instead of transmitting separate packets to each field device, the system combines all payload data into one packet structure, thereby reducing the total number of packets and improving bandwidth utilization efficiency while maintaining the same transmission speed to multiple devices.
2Loss of time
If separate Profinet frames are used for each field device, then data can be transmitted to each device individually, but high cycle times result due to repeated packet transmission
Solution Approach 1:
The patent combines multiple individual Profinet frame transmissions into a single aggregated Profinet frame that contains multiple data fields, each addressed to a different field device. This merging approach reduces the total transmission time by eliminating repeated packet transmission overhead, while the internal structure maintains individual addressability through data field identifiers.
Solution Approach 2:
The aggregated Profinet frame is segmented into multiple data fields within a single frame structure. Each data field is assigned to a specific field device through identification mechanisms, allowing individual data transmission to multiple devices while maintaining a unified transmission envelope that reduces overall cycle time.
3Adaptability or versatility
If minimum length Ethernet packets are used, then protocol compliance is maintained, but only a small number of subscribers can be active due to bandwidth constraints
Solution Approach 1:
The patent aggregates multiple data payloads for different field devices into a single Ethernet packet structure, thereby consolidating bandwidth usage. This approach allows more field devices (subscribers) to remain active simultaneously because the aggregated packet reduces the total number of transmissions required, effectively increasing available bandwidth for the network as a whole while maintaining protocol compliance.
Data Source
AI summary
The invention relates to a method for optimized transmission of data between a control device and a plurality of field devices that are connected to one another via an IP-based communications network, wherein the data transmission is controlled using a Profinet protocol. The invention further relates to a control and data transmission installation (10) that is particularly suited to the performance of the method. With the control and data transmission installation (10), it is possible to transmit the data to be transmitted from a control device (20) to a group of field devices (30, 40, 50) in a single sum frame subdivided into data fields, and to transmit the data to be transmitted from a plurality of field devices to a control device likewise in only one common sum frame subdivided into data fields. In this manner, the transmission rate can be optimized with respect to standard Profinet frames.