D/A Conversion Device High-Speed Waveform Output
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Solution Overview
Problem
Conventional D/A conversion devices in programmable logic controllers (PLCs) face limitations in achieving high D/A conversion rates due to the need for continuous digital value calculation, which slows down the output of waveforms and hampers debugging processes.
Innovation Solution
A conversion device with a waveform-data-string storage unit, a control-data storage unit, and a D/A conversion unit that allows for sequential output of digital values based on pre-set periods or update requests, enabling high-speed waveform output and debugging through automatic and manual address updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a digital value is calculated every time when the analog-signal processing device performs D/A conversion, then the D/A conversion can be performed continuously, but the D/A conversion rate cannot be sufficiently high
Solution Approach 1:
The patent pre-calculates and stores multiple digital values in advance in a memory unit before D/A conversion is needed. When D/A conversion is performed, the device simply retrieves pre-calculated digital values from memory rather than calculating them in real-time, thereby eliminating calculation time and achieving high conversion rates.
2Productivity
If a conventional D/A conversion device waits for digital values to be written from outside for each predetermined period, then the device operation is simple, but the actual D/A conversion rate is decreased
Solution Approach 1:
The device pre-prepares digital values in a waveform data string stored in memory before conversion is needed. This eliminates the need to wait for external writing of digital values during operation, allowing continuous high-speed conversion without increasing operational complexity.
Solution Approach 2:
The patent introduces a memory unit as an intermediary between the control device and D/A conversion unit. The memory unit stores pre-calculated digital values and supplies them to the D/A conversion unit, decoupling the conversion rate from the external writing rate and enabling high-speed conversion.
3Speed
If the address to be read is updated sequentially for each output period, then waveform output speed is maximized, but debugging capability is reduced
Solution Approach 1:
The patent makes the address update mechanism dynamic by providing two modes: automatic sequential update for high-speed waveform output, and manual update triggered by debug commands for debugging. The system adapts its operation mode based on the current task requirement, achieving both high speed and debuggability.
Solution Approach 2:
The patent changes the operational parameter of address update timing based on the mode. In waveform output mode, addresses update automatically at each output period for maximum speed. In debugging mode, address updates occur only when triggered by debug commands, allowing step-by-step verification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for rapid output of waveforms and facilitates debugging by enabling high-speed D/A conversion and address control, improving the overall efficiency and accuracy of waveform generation and verification.
Implementation Method 1
a D/A conversion unit that converts the digital value output by the digital-value output unit into an analog value
Data Source
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AI summary
To output a waveform as quick as possible and enable debugging of an output waveform, a D/A conversion device 100 includes a waveform-data-string storage area 142 that stores therein a waveform data string including a plurality of digital values, a waveform-output-control-data storage area 144 in which operation-mode specifying data and update request data are written, a digital-value output unit 133 that, when the operation-mode specifying data specifies an automatic control mode, while sequentially updating an address to be read in the waveform-data-string storage area 142 for each output period set in advance, sequentially reads and outputs a digital value and that, when the operation-mode specifying data specifies a step execution mode or an output-address change mode, while updating the address to be read at a timing when the update request data is written, reads and outputs the digital value, and a D/A conversion unit 120 that converts the digital value output from the digital-value output unit 133 into an analog value.