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US 10,838,385 B2Granted
Method for automatic switching of a communication resistor of a hart device in or out
AssigneeEndress + Hauser Process Solutions AG
InventorsFabian Bihler, Marc Fiedler
Life of this patent
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Abstract
Method for automatic switching of a communication resistor of a HART device in or out, wherein the method comprises steps as follows: transmitting a test signal on an electrical current loop; reading from the electrical current loop a test voltage signal, which is based on the transmitted test signal; comparing the test voltage signal with a reference signal; connecting the communication resistor into the electrical current loop when the test voltage signal exceeds the reference signal.
Claims7
A method for an automatic switching of a communication resistor of a HART device in or out, comprising:
- providing a HART device, including:
- a first interface configured to connect with a service unit;
- a second interface configured to connect with an electrical current loop;
- a microprocessor;
- a HART modem having a carrier detect signal, wherein the HART modem is connected to the microprocessor, including the carrier detect signal connected with the microprocessor;
- a communication resistor;
- a switch controlled by the microprocessor, wherein the switch is configured in a first state to connect the communication resistor with the second interface, and wherein the switch is configured in a second state to disconnect the communication resistor from the second interface;
- a filter element connected to the second interface and configured to filter out disturbance signals from a test voltage signal received via the second interface;
- and
- a comparator connected to an output of the filter element, wherein the comparator is configured to compare the filtered test voltage signal with a reference signal, and wherein an output of the comparator is connected to the microprocessor,
- wherein the microprocessor is configured to transmit a test signal on the electrical current loop, and to set the switch to the first state or to the second state based on the comparison of the filtered test voltage signal with the reference signal;
- connecting the HART device to an electrical current loop;
- transmitting the test signal on the electrical current loop;
- reading from the electrical current loop, via the second interface, the test voltage signal that is based on the transmitted test signal;
- filtering, via the filter element, disturbance signals from the test voltage signal;
- comparing, via the comparator, the filtered test voltage signal with a reference signal;
- and
- connecting the communication resistor into the electrical current loop or disconnecting the communication resistor from the electrical current loop based on the comparison of the filtered test voltage signal with the reference signal.
15 more elements
Dependencies are inferred from the claim text.