Temperature Control Unit for Accurate TPO Across Unsynced Cycles
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Solution Overview
Problem
Conventional temperature control systems experience deviations in time proportional output (TPO) due to the cycle time of the controller, leading to inaccuracies in ON/OFF time ratios for output apparatuses, especially when the cycle time is not synchronized with the TPO control cycle.
Innovation Solution
The output control system includes a temperature control unit that acquires an operation amount from the controller and performs time proportional output to the SSR, allowing for precise adjustment of the ON/OFF time ratios independently of the controller's cycle time, using a configuration that includes a determination unit to assess the heater's disconnection and a warning output unit to notify the controller of any discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the controller calculates ON/OFF times using a user program based on setting values and control cycle, then the system can perform time proportional output control, but deviations occur in TPO due to mismatch between controller cycle time and TPO control cycle
Solution Approach 1:
The patent introduces an intermediate calculation process within the controller that computes ON/OFF times based on the relationship between the control cycle and TPO control cycle. This intermediary calculation layer translates the setting values into accurate ON/OFF timing instructions that account for cycle time mismatches, thereby eliminating TPO deviations without requiring hardware changes or external synchronization mechanisms.
2Adaptability or versatility
If the controller cycle time is not synchronized with the TPO control cycle, then the system can operate independently with different cycle times, but this causes deviations in the ON/OFF time ratio of the output apparatus
Solution Approach 1:
The patent dynamically adjusts the calculation parameters for ON/OFF timing based on the actual control cycle time and TPO control cycle time. By changing the computational parameters (cycle time ratios, division factors) rather than the physical cycle times themselves, the system maintains independent operation while achieving precise ON/OFF time ratios. The controller calculates appropriate ON/OFF durations by considering the ratio between its own cycle time and the TPO control cycle, ensuring accuracy regardless of synchronization status.
Data Source
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Figure 3(a)~3(b)
AI summary
Deviation of TPO due to a cycle time of a controller is reduced. A temperature control unit (3) includes an acquisition unit (30) that acquires an operation amount from a controller (2), and an SSR control unit (32) that performs time proportional output of an instruction to drive or stop a heater (7) to SSR (8) after reflecting the operation amount.