Wireless HART Adapter With Switchable Resistor for Error-Free Loops
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Solution Overview
Problem
Existing automation systems face challenges in error-free HART communication from an operating unit to a field device, particularly when an external HART communication resistor is already installed in the two-wire line.
Innovation Solution
A field device adapter with internal communication resistor switching capabilities via radio signals, using adapter electronics and radio modules to selectively enable or disable the communication resistor, allowing for wireless control and modulation of HART-based two-wire signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an internal communication resistor is integrated into the field device adapter, then HART communication can be enabled, but communication errors occur when an external HART communication resistor is already installed in the two-wire line
Solution Approach 1:
The patent implements a dynamically switchable communication resistor that can be activated or deactivated via radio signal control. This dynamic configuration allows the adapter to adapt to different installation scenarios: when no external resistor is present, the internal resistor is activated to enable HART communication; when an external resistor is already installed, the internal resistor remains deactivated, preventing communication conflicts. This resolves the technical contradiction by making the resistor configuration flexible rather than fixed.
Solution Approach 2:
The patent changes the operational state parameter of the communication resistor from a fixed state to a controllable state. By introducing radio signal-controlled switching, the resistor's activation status becomes a variable parameter that can be adjusted based on the presence of external resistors. This parameter change enables the system to optimize communication reliability for each specific installation configuration.
2Ease of operation
If a HART communication resistor is always active in the adapter, then HART communication is always enabled, but it causes communication errors when an external resistor is already installed
Solution Approach 1:
The patent implements a feedback mechanism where the adapter detects the presence of external HART communication resistors through radio signal communication and automatically adjusts the internal resistor's activation state accordingly. This feedback loop ensures that the communication configuration is always optimal for the current installation scenario, preventing communication errors while maintaining ease of operation. The system self-adjusts based on detected conditions rather than requiring manual configuration.
3Reliability
If manual configuration of the communication resistor is required, then the system can adapt to external resistors, but the complexity of installation and configuration increases
Solution Approach 1:
The patent enables the field device adapter to automatically detect its installation environment and self-configure the communication resistor activation state without requiring manual intervention. The adapter uses radio signal communication to detect whether external HART communication resistors are present and automatically activates or deactivates its internal resistor accordingly. This self-service capability eliminates the need for manual configuration while ensuring accurate communication setup, thereby reducing installation complexity while maintaining configuration accuracy.
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 error-free HART communication by allowing selective switching of the internal communication resistor, accommodating external resistors and ensuring uninterrupted data transmission between field devices and higher-level units.
Implementation Method 1
a first radio signal received by the adapter electronics can be translated into a, preferably HART-based, two-wire signal and modulated onto the loop current via the tap point
Implementation Method 2
In HART, a frequency signal is superimposed on the analog 4-20 mA current signal as a digital two-wire signal for data transmission. According to the HART protocol, the data transmission frequency switches between 1200 Hz and 2200 Hz
Implementation Method 3
the adapter electronics are configured to wirelessly receive a second radio signal and to control the circuit for short-circuiting the communication resistor by means of the second radio signal
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The invention relates to a field device adapter (6) for HART communication with a field device (1), at least comprising: - an adapter housing (7) having an adapter chamber (10); - adapter electronics (14) arranged in the adapter chamber (10), which are designed to wirelessly receive a second radio signal and, by means of the second radio signal, to control a circuit for shorting the communication resistor (27) in such a manner that at least one communication resistor (18) can be selectively switched on or switched off by radio such that, in a bridged state, a first radio signal received by the adapter electronics (14) can be translated into a, preferably HART-based, two-conductor signal and can be modulated on to the loop current (I) via the tapping point (23).