Field Adapter Circuit for Low-Power Wireless Retrofit
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Solution Overview
Problem
Two-wire field devices in process automation systems face limitations in energy supply, making it difficult to retrofit them with wireless data transmission adapters due to energy constraints.
Innovation Solution
A field device adapter with a radio module for low-power wide area network communication, an energy storage system, and adapter electronics that convert and manage energy to enable wireless data transmission while adhering to the maximum energy requirements, allowing for retrofitting without exceeding the energy supply limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a field device adapter for wireless data transmission is retrofitted to a two-wire field device, then wireless communication capability is improved, but energy consumption exceeds the maximum energy available from the two-wire connection
Solution Approach 1:
The adapter performs preliminary actions by continuously charging an energy storage device (capacitor) during periods when the field device is operating normally, accumulating energy before it is needed for wireless transmission. This allows the radio module to have sufficient energy for transmission without requiring continuous high power supply that would exceed the two-wire connection limits.
Solution Approach 2:
The radio module operates periodically rather than continuously - it transmits data packets at specific intervals when the energy storage device has sufficient charge, and remains inactive when energy is being recharged. This periodic operation pattern allows the system to function within the energy constraints of the two-wire connection while still providing wireless communication capability.
2Productivity
If the radio module continuously transmits data packets, then data transmission frequency is improved, but energy consumption exceeds the limited energy supply from the two-wire connection
Solution Approach 1:
The radio module transmits data packets periodically at predetermined intervals rather than continuously. The adapter electronics monitor the charge level of the energy storage device and only enable transmission when sufficient energy is available, creating a periodic transmission pattern that balances data transmission frequency with energy availability from the limited two-wire supply.
Solution Approach 2:
The adapter electronics continuously monitor the charge level of the energy storage device and use this feedback to control when the radio module transmits data packets. This feedback mechanism ensures that transmission frequency is dynamically adjusted based on available energy, preventing energy depletion while maintaining optimal data transmission when energy permits.
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
Enables wireless data transmission for field devices by efficiently managing energy storage and usage, allowing for the retrofitting of existing two-wire field devices with wireless capabilities without increasing their energy demand.
Implementation Method 1
an energy storage device (18), in particular a capacitor, and the adapter electronics have a boost converter (17)
Implementation Method 2
the adapter electronics have a boost converter which is configured to convert a voltage applied to the field device's internal interface to a voltage that is higher relative to the applied voltage
Data Source
Figure 1
AI summary
The invention relates to a field device adapter for wireless data transfer (5) for connection to a field-device-internal interface (15) provided for a display (14) of a field device (1), comprising: -an interface (5a) for connection to the field-device-internal interface (15); -a radio module (6), which is configured to wirelessly transmit a data packet in accordance with a standard of a low-power wide-area network, wherein the radio module (6) is further configured to only transmit the data packet and not to receive any data packets; -adapter electronics (10, 16, 17, 18), which are configured to limit an energy provided via the field-device-internal interface (15) to a predefined value and to charge a stored energy source (18) with the limited energy, wherein the predefined value is determined such that the value corresponds at most to a maximum energy requirement of the display (14), and the adapter electronics (10, 16, 17, 18) are further configured to monitor a state of charge of the stored energy source (18) and, based on the state of charge, to provide the radio module (6) with an energy originating from the stored energy source (18) for transmitting the data packet so that the radio module (6) transmits the data packet.