Master-Slave PLC Control Device for Dynamic Uplink Power Management
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Solution Overview
Problem
The increasing scale of Programmable Logic Controller (PLC) systems necessitates a larger number of IO units, while there is a growing demand for reducing power consumption in industrial devices such as PLCs.
Innovation Solution
A control device comprising a master control unit and slave control units connected via a communication line with a downlink for data transmission from the master to the slave and an uplink for data transmission from the slave to the master, where the master unit transmits instructions to deactivate the uplink after data transmission and activate it as needed, with the slave unit keeping the downlink active and deactivating/upgrading the uplink according to master unit instructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of IO units is increased to expand PLC system scale, then the system functionality and processing capacity are improved, but the total power consumption of the system increases
Solution Approach 1:
The patent implements dynamic power management by enabling slave control units to alternately activate and deactivate their communication circuits based on master unit instructions. This dynamic switching allows the system to maintain expanded functionality with multiple IO units while reducing power consumption during periods when slave units do not need to transmit data, directly resolving the contradiction between system scale and power consumption.
Solution Approach 2:
The master control unit periodically activates slave control units only when data transmission is required, rather than maintaining continuous operation. This periodic activation pattern allows the PLC system to support a larger number of IO units for enhanced functionality while significantly reducing overall power consumption by keeping slave units in a low-power state during inactive periods.
2Reliability
If the uplink communication circuit is kept active in slave control units, then data transmission capability is maintained, but power consumption increases
Solution Approach 1:
The slave control units dynamically switch their uplink communication circuits between active and inactive states based on real-time transmission needs. When the master unit requires data from a slave unit, it sends an activation instruction; when no transmission is needed, the slave unit deactivates its uplink circuit. This dynamic state switching maintains data transmission reliability when needed while minimizing power consumption during inactive periods.
Solution Approach 2:
The slave control units automatically respond to master unit instructions by activating or deactivating their own communication circuits without requiring continuous external control. This self-service mechanism allows the system to maintain reliable data transmission capability while significantly reducing power consumption, as each slave unit manages its own power state based on received instructions.
3Speed
If high clock frequency is used in communication lines, then transmission speed and bandwidth are improved, but power consumption and noise sensitivity increase
Solution Approach 1:
The system uses high clock frequency for data transmission only during periodic activation intervals when the master unit requires communication with slave units. During the majority of time when no transmission is needed, the communication circuits are deactivated. This periodic use of high-speed communication maintains transmission performance when required while dramatically reducing the average power consumption associated with maintaining continuous high-frequency operation.
Data Source
AI summary
Provided is a control device capable of reducing power consumption in a control system. The control device includes a master control unit and at least one slave control unit that is connected to the master control unit via a communication line. The master control unit includes a circuit for, upon completion of data transmission from the slave control unit via an uplink, transmitting an instruction for deactivating the uplink to the slave control unit via a downlink, as well as a circuit for, in order to obtain data from the slave control unit, transmitting an instruction for activating the uplink to the slave control unit via the downlink. The slave control unit includes a circuit for keeping the downlink active, and for activating/deactivating the uplink in accordance with an instruction from the master control unit transmitted via the downlink.