Slave Device Watchdog Circuit for Continuous Field Network Communication
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Solution Overview
Problem
In control systems with one-chip microcontrollers, a watchdog timeout disrupts communication across field networks because the reset circuit shared by the CPU and communication controller stops both operations, leading to communication interruptions.
Innovation Solution
A control system where the watchdog circuit resets only the processor during a timeout, while continuing the operation of the communication controller, allowing communication to persist and enabling error signaling to inform the master device of malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If force commands are transmitted during communication suspension periods, then responsiveness is improved, but power consumption increases
Solution Approach 1:
The control device dynamically adjusts the communication suspension period based on operation type: longer suspension periods for non-force commands (saving power) and shorter or no suspension for force commands (maintaining responsiveness). This dynamic adaptation resolves the contradiction by making the system flexible rather than static.
Solution Approach 2:
The system changes the communication timing parameters adaptively - extending suspension periods when force commands are not expected, and reducing or eliminating them when force commands need to be transmitted. This parameter adjustment allows the system to optimize between power consumption and responsiveness based on operational context.
2Use of energy by moving object
If communication suspension period is extended, then power consumption is reduced, but responsiveness deteriorates
Solution Approach 1:
The communication suspension period is made dynamic rather than fixed. The control device extends suspension periods during normal operation to save power, but automatically reduces or eliminates the suspension when force commands need to be transmitted, thus maintaining responsiveness when needed while achieving power savings during steady-state operation.
Solution Approach 2:
The system adaptively changes the communication timing parameters based on operational requirements. By adjusting the suspension period duration according to whether force commands are expected, the system optimizes the trade-off between power consumption and responsiveness in different operational contexts.
3Speed
If force command transmission is prioritized, then responsiveness is improved, but communication stability deteriorates
Solution Approach 1:
The control device applies different communication strategies to different command types: force commands receive priority transmission with reduced or eliminated suspension periods to ensure responsiveness, while non-force commands use extended suspension periods for power saving. This localized differentiation resolves the contradiction by treating different command types with appropriate quality levels.
Data Source
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AI summary
Amain control section (30) of a slave device (3) include a slave controller (31), a processor (32), and a watchdog circuit (33) which are configured as a one-chip integrated circuit. In a case where the watchdog circuit (33) has detected that a malfunction has occurred in an operation of the main control section (30), the watchdog circuit (33) resets the processor (32) while not stopping an operation of the slave controller (31).