Method for determining sensor types and sensor wiring
AssigneeABB Schweiz AG
InventorStefan Pook
Life of this patent
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Abstract
A system and method for determining the type of an analog sensor device in a process control system comprising at least a terminal block unit comprising four connection ports connectable with an analog sensor device, wherein the sensor device to be determined is a 2-wire connection sensor device, a 3-wire connection sensor device, or a 4-wire connection sensor device. The method includes detecting whether: a predefined resistance value is present for a 2-wire connection sensor device, a 3-wire connection sensor device, a predefined resistance value between two predefined pairs of connection ports of the terminal block unit is provided, or a 4-wire connection sensor device is connected to the terminal block unit.
Claims8
A method for determining a type of an analog sensor device in a process control system comprising at least a terminal block unit comprising four connection ports connectable with an analog sensor device, wherein the sensor device to be determined is a 2-wire connection sensor device, a 3-wire connection sensor device, or a 4-wire connection sensor device, the method comprising the following steps:
- a) detecting whether a predefined resistance value is present for a 2-wire connection sensor device at the connection ports of the terminal block unit provided for the 2-wire connection sensor device;
- b) when a predefined resistance value for a 2-wire connection sensor is detected in step a), further detecting whether a predefined resistance value is present for a 3-wire connection sensor device at the connection ports of the terminal block unit provided for the 3-wire connection sensor device;
- c) when no predefined resistance value for a 3-wire connection sensor device is detected in step b) determine that a 2-wire connection sensor device is connected to the terminal block unit;
- when a predefined resistance value for a 3-wire connection sensor device is detected in step b), further detecting whether a predefined resistance value between two predefined pairs of connection ports of the terminal block unit is provided;
- d) when only between one of the two predefined pairs of connection ports of the terminal block unit a predefined resistance value is detected in step c), determine that a 3-wire connection sensor device is connected to the terminal block unit;
- and
- when between two of the two predefined pairs of connection ports of the terminal block unit a predefined resistance value is detected in step c), determine that a 4-wire connection sensor device is connected to the terminal block unit,
- wherein the analog sensor device is a resistance temperature detector (RTD) device or a thermocouple (TC) device,
- wherein the resistance temperature detector device is a compensated resistance temperature detector device, wherein the compensated resistance temperature detector device comprises a cold junction compensation, an internal compensation or a fixed compensation by parameter, and
- wherein the method further comprises:
- detecting a cold junction temperature of the compensated resistance temperature detector device;
- when the detected cold junction temperature is within a predefined temperature range, determine that the resistance temperature detector device comprises a cold junction compensation;
- and
- when the detected cold junction temperature is not within a predefined temperature range, determine that the resistance temperature detector device comprises an internal compensation or a fixed compensation by parameter.
A system for determining a type of an analog sensor device in a process control system comprising at least a terminal block unit comprising four connection ports connectable with an analog sensor device, wherein the sensor device to be determined is a 2-wire connection sensor device, a 3-wire connection sensor device, or a 4-wire connection sensor device, comprising:
- a) a detection unit configured to detect whether a predefined resistance value is present for a 2-wire connection sensor device at the connection ports of the terminal block unit provided for the 2-wire connection sensor device;
- b) a detection unit configured to further detect whether a predefined resistance value is present for a 3-wire connection sensor device at the connection ports of the terminal block unit provided for the 3-wire connection sensor device, in case, a predefined resistance value for a 2-wire connection sensor is detected in step a);
- c) a determination unit configured to determine that a 2-wire connection sensor device is connected to the terminal block unit, in case, no predefined resistance value for a 3-wire connection sensor device is detected in step b);
- a detection unit configured to further detect whether a predefined resistance value between two predefined pairs of connection ports of the terminal block unit is provided, in case, a predefined resistance value for a 3-wire connection sensor device is detected in step b);
- d) a determination unit configured to determine that a 3-wire connection sensor device is connected to the terminal block unit, in case, only between one of the two predefined pairs of connection ports of the terminal block unit a predefined resistance value is detected in step c);
- and
- a determination unit configured to determine that a 4-wire connection sensor device is connected to the terminal block unit, in case, between two of the two predefined pairs of connection ports of the terminal block unit a predefined resistance value is detected in step c),
- wherein the analog sensor device is a resistance temperature detector (RTD) device or a thermocouple (TC) device,
- wherein the resistance temperature detector device is a compensated resistance temperature detector device, wherein the compensated resistance temperature detector device comprises a cold junction compensation, an internal compensation or a fixed compensation by parameter, and
- wherein the system further comprises:
- a detection unit configured to detect a cold junction temperature of the compensated resistance temperature detector device;
- a determination unit configured to determine that the resistance temperature detector device comprises a cold junction compensation, in case, the detected cold junction temperature is within a predefined temperature range;
- and
- a determination unit configured to determine that the resistance temperature detector device comprises an internal compensation or a fixed compensation by parameter, in case, the detected cold junction temperature is not within a predefined temperature range.
Dependencies are inferred from the claim text.