SDO Group Control for Shared Setpoint Devices With Master Election
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Solution Overview
Problem
Current data center systems are limited in the number of devices that can be networked together due to communication constraints, and manual intervention is required to designate a new master device when one fails, leading to inefficiencies and potential downtime.
Innovation Solution
The implementation of the Service Data Objects (SDO) protocol to expand the number of devices in a group, enable redundant master control, and optimize communication efficiency by prioritizing frame transmissions and using suppression mechanisms, allowing for larger-scale group communication and automatic master election.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional Ethernet-based approaches are used for device communication, then communication setup is straightforward, but the number of devices that can be networked together is limited due to Ethernet switching capacity constraints
Solution Approach 1:
The patent replaces Ethernet-based communication infrastructure with a serial communication bus system using the CANopen protocol. This substitution eliminates the need for Ethernet switches and complex network infrastructure, allowing hundreds of devices to be networked together using simple daisy-chain wiring. The serial communication approach fundamentally changes the physical layer from packet-switched Ethernet to deterministic serial bus communication.
2Reliability
If a master device fails in traditional setups, then system reliability decreases, but manual intervention is required to designate a new master causing downtime
Solution Approach 1:
The patent implements automatic master election functionality where slave devices are pre-configured with election parameters (such as node IDs and priority levels) that enable them to automatically assume master role when the current master fails. This preliminary configuration eliminates the need for manual intervention during failover events, ensuring continuous system operation. The election algorithm is pre-programmed into each device's controller.
3Loss of information
If all device controllers continuously transmit status updates, then communication completeness is ensured, but busload increases reducing communication efficiency
Solution Approach 1:
The patent implements event-triggered communication where device controllers transmit status updates only when changes occur rather than continuously. Each controller monitors its local state and transmits SDO messages only when parameters change, reducing bus traffic while ensuring all relevant information is communicated. This periodic/event-driven approach maintains communication completeness while significantly improving bus utilization efficiency.
4Ease of operation
If frame transmissions are sent without prioritization, then transmission simplicity is maintained, but critical communications may be delayed
Solution Approach 1:
The patent assigns different priority levels to different types of frame transmissions based on their criticality. Control commands and alarm messages are assigned high priority for immediate transmission, while status updates and diagnostic information receive lower priority. Each device's controller locally determines transmission priority based on message type, ensuring critical communications are transmitted quickly without requiring complex centralized scheduling.
Data Source
AI summary
Techniques for group control using service data objects (SDO) are disclosed. A device controller is configured to perform operations including: receiving, from device controllers that are configured to control devices so that the devices operate based on a shared set point, SDO messages using an SDO protocol; determining that the device controller is a master device controller for the device controllers, based at least on the SDO messages; and sending a setpoint update message including a modified value of the shared set point, using the SDO protocol, to slave device controllers in the device controllers, wherein a slave device controller in the slave device controllers is configured to adjust operation of at least one slave device in the devices, based at least on the setpoint update message.