Setting device, setting method, and setting program

Abstract

To achieve reduction of power consumption in a loop.SOLUTION: A setting device 10 includes: a converter for converting a physical quantity into a current value; a communication section for performing communication to acquire a second current output range which is a current output range of a transmission signal via a loop formed with an input / output device for outputting the current value input from the converter to a system and also where the minimum current value or the maximum current value is smaller than that of a first current output range; and a setting section for setting a current output corresponding to the first current output range or the second current output range based on whether the second current output range is successively acquired.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a setting device, a setting method, and a setting program.

Background Art

[0002] When measuring physical quantities such as differential pressure, temperature, and flow rate in a plant or the like, a two-wire transducer is used. The two-wire transducer converts a measured value such as a flow rate or differential pressure into a current value of 4 - 20 mA, which is the current output range of an instrumentation unified signal, and transmits it to an input / output device, which is a power supply source, via a loop formed by two wires in which the power supply and the signal lines are shared in the same cable. The input / output device supplies a DC voltage of 24 V to the two-wire transducer and converts the current value of 4 - 20 mA transmitted from the two-wire transducer into a signal required by the system.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the above 4 - 20 mA is a world standard as an instrumentation transmission signal established by the IEC (International Electrotechnical Commission), it remains untouched as an inviolable area, so there is an aspect that it is difficult to reduce the power consumption of the above loop.

[0005] An object of the present invention is to realize power reduction of the loop.

Means for Solving the Problems

[0006] The setting device according to one aspect of the present invention includes a communication unit that executes communication to obtain a current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, and the current output range has a second current output range in which the minimum current value or the maximum current value is smaller than that of a first current output range, and a setting unit that sets a current output corresponding to either the first current output range or the second current output range based on whether or not the acquisition of the second current output range is successful.

[0007] In the setting method according to one aspect of the present invention, communication is executed to obtain a current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, and the current output range has a second current output range in which the minimum current value or the maximum current value is smaller than that of a first current output range, and based on whether or not the acquisition of the second current output range is successful, a processor executes a process of setting a current output corresponding to either the first current output range or the second current output range.

[0008] The setting program according to one aspect of the present invention causes a processor to execute a process of executing communication to obtain a current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, and the current output range has a second current output range in which the minimum current value or the maximum current value is smaller than that of a first current output range, and based on whether or not the acquisition of the second current output range is successful, setting a current output corresponding to either the first current output range or the second current output range.

Advantages of the Invention

[0009] According to one embodiment, power reduction of the loop can be realized.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 10

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the setting device, setting method, and setting program according to the present application (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. Each embodiment is merely an example, and the configuration, structure, function, numerical values used for these specifications, application scenarios, etc. are not limited by such examples. And each embodiment can be adaptively combined within a range that does not conflict with the processing content.

[0012] <Overall Configuration> FIG. 1 is a block diagram showing an example of the functional configuration of a setting device. The setting device 10 shown in FIG. 1 provides a setting function for setting the current output of an instrumentation transmission signal transmitted and received via a loop formed between a converter that converts a physical quantity measured in a plant or the like into a current value and an input / output device that outputs the current value input from the converter to a system.

[0013] On one aspect, the setting device 10 may be realized as a converter or an input / output device. For example, the converter may be a field device installed in a plant, such as an instrumentation device that measures physical quantities such as differential pressure, temperature, and flow rate. Also, the input / output device may be a DCS (Distributed Control Systems) or a PLC (Programmable Logic Controller). Note that the setting device 10 may be realized as a control device communicably connected to the converter or the input / output device.

[0014] <4-20mA> An operation example of the entire loop using a 4-20 mA signal will be described. FIG. 2 is a schematic diagram showing an operation example of the entire loop. As shown in FIG. 2, between the input / output device 30 and the two-wire converter 50, a loop 3 is formed by two wires in which the power supply and signal lines are shared in the same cable.

[0015] Hereinafter, in the present embodiment, as an example of the converter, a two-wire converter will be given as an example, but the connection method of the converter is not limited to two-wire. Note that although details will be described later with reference to FIG. 13, it is preliminarily noted that the connection method of the converter may be three-wire or four-wire.

[0016] On one aspect, the loop 3 functions as a power supply line. For example, in the loop 3, a 24V DC voltage is supplied from the input / output device 30 to the two-wire converter 50, and thus the two-wire converter 50 operates with the 24V DC voltage.

[0017] As another aspect, loop 3 also functions as a signal output line. For example, the two-wire transducer 50 converts the measured value of a physical quantity such as flow rate or differential pressure into a current value of 4 - 20 mA, which is the current output range of the instrumentation unified signal, and transmits the current value to the input / output device 30 via loop 3.

[0018] The current value transmitted to the input / output device 30 in this way is converted into the signal required by the system 70 and then output to the system 70. Further, the system 70 converts the voltage value output by the input / output device 30 into a process value (%).

[0019] For example, the system 70 may be realized as a plant information management system (Plant Information Management System) that manages the time-series data of the process value as historian data.

[0020] The current output range used in such loop 3, that is, 4 - 20 mA, is a world standard as an instrumentation transmission signal. In the early days when automatic control began to be used in the process, the signal current values transmitted were different depending on the manufacturer. When the manufacturers of the input / output device 30 and the two-wire transducer 50 were different, it was difficult to ensure compatibility in signal transmission and reception. However, by being unified to a current value of 4 - 20 mA in IEC 381 (later IEC 60381-1), the connection between the input / output device 30 and the two-wire transducer 50 has become easier, which has greatly contributed to the development of automatic control.

[0021] The first advantage of the 4 - 20 mA signal is that it is a current signal. Since it is not a voltage signal, the signal amplitude does not attenuate in proportion to the cable length. The second advantage is that it is a DC signal. Since it is not an AC signal, it is possible to easily remove noise with a low-pass filter and is resistant to noise.

[0022] <One aspect of the problem> The environment in the world has changed greatly, and it has become important for companies to contribute to the SDGs (Sustainable Development Goals).

[0023] Each manufacturer is developing products aiming for lower power consumption, but they are still at a loss when it comes to reducing the power consumption determined by the instrumentation unified signal (4 - 20mA signal) and its power supply voltage (24V). One of the reasons for this is that since the instrumentation unified signal and its power supply voltage are world standards, no one in the industry wants to change them.

[0024] For example, in the example shown in Figure 2, since the power [W] of 24V×(4 - 20mA) is consumed in the entire loop 3, the power consumption increases in proportion to 24V and 4 - 20mA.

[0025] <One aspect of the problem - solving approach> Therefore, in this embodiment, a low - current mode is introduced in both the input / output device 30 and the two - wire converter 50, in which they operate in a current output range smaller than the minimum current value or the maximum current value of the 4 - 20mA current output range corresponding to the instrumentation unified signal.

[0026] Hereinafter, the 4 - 20mA current output range corresponding to the instrumentation unified signal may be referred to as the "first current output range", and the mode of operating in the first current output range may be referred to as the "standard mode". Further, the current output range corresponding to the low - current mode may be referred to as the "second current output range".

[0027] When the low - current mode is introduced in this way, an environment is constructed in which both the input / output device 30 and the two - wire converter 50 co - exist in the standard mode and the low - current mode. In this case, an environment may occur in which the low - current mode is not necessarily operable in both the input / output device 30 and the two - wire converter 50.

[0028] This is because the timing of introducing each of the input / output device 30 and the two-wire converter 50 into a plant or the like may be different, or even if the introduction timing is the same, the manufacturers of the input / output device 30 and the two-wire converter 50 may be different.

[0029] In such an environment, different modes may be set between the input / output device 30 and the two-wire converter 50, or even though one of the devices of the input / output device 30 and the two-wire converter 50 is inoperable in the low-current mode, the low-current mode may be set. In these cases, malfunctions occur in the operations of the input / output device 30 and the two-wire converter 50, so the input / output device 30 and the two-wire converter 50 cannot perform normal operations.

[0030] Therefore, in the present embodiment, a setting function for setting a current output corresponding to either the standard mode or the low-current mode is implemented according to whether the acquisition of the second current output range from the input / output device 30 and the two-wire converter 50 is successful.

[0031] For example, when the acquisition of the second current output range is successful, the current output corresponding to the low-current mode can be set, while when the acquisition of the second current output range fails, the current output corresponding to the standard current mode can be set.

[0032] For this reason, it becomes possible to operate both devices of the input / output device 30 and the two-wire converter 50 normally when the low-current mode is introduced.

[0033] Therefore, according to the setting function according to the present embodiment, power reduction of the loop can be realized.

[0034] <Configuration of the setting device 10> Next, a functional configuration example of the setting device 10 having the above setting function will be described. In FIG. 1, blocks related to the setting function of the setting device 10 are schematically shown. As shown in FIG. 1, the setting device 10 includes a communication unit 11, a voltage adjustment unit 13, a setting unit 15, and an operation control unit 17. Note that FIG. 1 only shows an excerpt of the functional units related to the above setting function, and it is also possible that the setting device 10 is provided with functional units other than those shown in the figure.

[0035] The communication unit 11 is a processing unit that executes digital communication between the input / output device 30 and the two-wire converter 50. Such digital communication may be realized, for example, by a hybrid communication method in which a digital signal is superimposed on an analog signal transmitted via loop 3, such as HART (Highway Addressable Remote Transducer).

[0036] FIG. 3 is a diagram showing an example of HART communication. FIG. 3 shows an example in which an analog signal in the first current output range, that is, 4 - 20 mA, is transmitted and received via loop 3 between the input / output device 30 and the two-wire converter 50. As shown in FIG. 3, a frequency signal indicating "0" or "1" is superimposed on the 4 - 20 mA analog signal. Thereby, bidirectional digital communication can be realized between the input / output device 30 and the two-wire converter 50.

[0037] Through such digital communication, the input / output device 30 can set the status, parameters, etc. of the two-wire converter 50, and the two-wire converter 50 can transmit the measured value of the physical quantity to the input / output device 30.

[0038] The voltage adjustment unit 13 is a processing unit that adjusts the DC voltage supplied from the input / output device 30 to the two-wire converter 50. Hereinafter, the DC voltage supplied from the input / output device 30 to the two-wire converter 50 may be referred to as the "supply voltage".

[0039] Here, in the present embodiment, in addition to the above low-current mode, the supply voltage of the input / output device 30 is made variable, and a low-voltage mode is further introduced in which the input / output device 30 operates at a supply voltage value that is equal to or lower than a standard voltage value, for example, a supply voltage value corresponding to 24V.

[0040] From the aspect of realizing the introduction of such a low-voltage mode, the minimum supply voltage value at which both the input / output device 30 and the two-wire converter 50 can operate is stored in both devices. Hereinafter, the minimum supply voltage value at which the input / output device 30 or the two-wire converter 50 can operate may be referred to as the "minimum supply voltage value".

[0041] Based on the minimum supply voltage values stored in each of the input / output device 30 and the two-wire converter 50, the voltage adjustment unit 13 adjusts the supply voltage value at which both the input / output device 30 and the two-wire converter 50 can operate.

[0042] More specifically, the voltage adjustment unit 13 can execute the following processing when the input / output device 30 and the two-wire converter 50 are started up. That is, the voltage adjustment unit 13 causes the input / output device 30 to supply a standard voltage value, for example, a DC voltage of 24V, to the two-wire converter 50. Supplying the standard 24V voltage immediately after startup has the aspect of suppressing a situation in which the two-wire converter 50 becomes inoperable before the supply voltage is adjusted.

[0043] Then, when the minimum supply voltage value is stored in a register or the like of the input / output device 30, the voltage adjustment unit 13 starts supplying a DC voltage corresponding to the minimum supply voltage value from the input / output device 30 to the two-wire converter 50. The two-wire converter 50 outputs a fixed maximum current value from the aspect of maximizing the voltage drop in the path. Thereafter, the voltage adjustment unit 13 searches for the supply voltage value at which both the input / output device 30 and the two-wire converter 50 can operate and which is the lower limit.

[0044] As an example of such a method for searching for a supply voltage value, a linear search that sequentially searches for values from the beginning is given as an example. However, this is merely an example, and other search methods, such as binary search that searches for values while narrowing down the range by half, may be applied to the search for the supply voltage value.

[0045] For example, the voltage adjustment unit 13 repeatedly executes a supply voltage adjustment process in which, until an OK flag indicating that the supply voltage is OK is responded from the input / output device 30 to the two-wire converter 50, a predetermined voltage value is added to the previous supply voltage value to update the supply voltage value while supplying a DC voltage corresponding to the updated supply voltage value. When the minimum supply voltage value is not stored in a register or the like of the input / output device 30, it is determined that the input / output device 30 can only operate with the standard supply voltage value, so the supply voltage adjustment is not executed.

[0046] Here, when supplying voltage from the input / output device 30 to the two-wire converter 50, the voltage adjustment unit 13 determines whether the two-wire converter 50 can operate with the supply voltage from the input / output device 30.

[0047] That is, when an equivalent resistance exists in the middle of loop 3, the supply voltage from the input / output device 30 drops according to Ohm's law until it reaches the two-wire converter 50. As one aspect, the greater the equivalent resistance value, the greater the drop in the supply voltage. As another aspect, the greater the current value, the greater the drop in the supply voltage. The "equivalent resistance" mentioned here refers to a factor that can be regarded as equivalent to the substantial existence of a resistance, and examples include wiring such as cables, contact resistance, or contact resistance. Note that the equivalent resistance does not necessarily mean a resistance element. In some cases, the equivalent resistance existing in the path from the input / output device 30 to the two-wire converter 50 on loop 3 is referred to as "path resistance". From the aspect of searching for a supply voltage value at which the two-wire converter 50 can operate including the voltage drop due to this path resistance, when the voltage received on the two-wire converter 50 side satisfies the operating voltage, an OK flag is returned to the input / output device 30 side.

[0048] FIG. 4 is a schematic diagram showing an example of path resistance. As shown in FIG. 4, a supply voltage V1 is supplied from the input / output device 30, and the two-wire converter 50 outputs the maximum value of the current. In the supply voltage V1 thus supplied from the input / output device 30, a voltage drop V3 occurs due to the path resistance. As a result of the influence of this voltage drop V3, the voltage reaching the two-wire converter 50 becomes V1 - V3. Subsequently, the voltage adjustment unit 13 compares the voltage value (V1 - V3) of the voltage reaching the two-wire converter 50 with the minimum operating voltage V2 stored in a register or the like of the two-wire converter 50. For example, the voltage adjustment unit 13 determines whether the voltage value (V1 - V3) of the voltage reaching the two-wire converter 50 is equal to or greater than the minimum operating voltage V2 of the two-wire converter 50, that is, whether (V1 - V3) ≥ V2.

[0049] Here, when (V1 - V3) < V2, the two-wire converter 50 cannot operate, so it cannot respond with an OK flag. In this case, since the input / output device 30 cannot confirm the OK flag, the input / output device 30 executes an update to increase the supply voltage V1 by adding a voltage value of an arbitrary step width, for example, 1 V or 3 V, to the supply voltage V1, and supplies a DC voltage corresponding to the updated supply voltage V1. Thereafter, when the voltage (V1 - V3) reaching the two-wire converter 50 becomes equal to or greater than the minimum operating voltage V2 of the two-wire converter 50, the two-wire converter 50 becomes operable. As a result, an OK flag is responded from the two-wire converter 50 to the input / output device 30. The supply voltage V1 in response to which the OK flag is thus responded is determined as the final adjustment result of the supply voltage.

[0050] The setting unit 15 is a processing unit that executes various settings, for example, settings such as current output, supply voltage, and transmission method. For example, when a DC voltage corresponding to a standard supply voltage value is supplied at startup, or after voltage adjustment by the voltage adjustment unit 13, the setting unit 15 causes the communication unit 11 to execute digital communication for acquiring a second current output range from each of the input / output device 30 and the two-wire converter 50.

[0051] On one side, when digital communication is possible between the setting unit 15, the input / output device 30, and the two-wire converter 50, that is, in the auto mode, the setting unit 15 performs automatic setting of any one of the following mode 1 to the following mode 4. That is, the setting unit 15 determines whether it has successfully obtained the second current output range from both the input / output device 30 and the two-wire converter 50, and whether information on the minimum supply voltage value exists in the register or the like of the input / output device 30, and then performs automatic setting of the following mode 1 to the following mode 4.

[0052] (1) Setting of mode 1 For example, when the acquisition of the second current output range is successful from both the input / output device 30 and the two-wire converter 50, and information on the minimum supply voltage value exists in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to mode 1. For example, the setting unit 15 sets, as the current output of mode 1, the larger of the two minimum current values, i.e., the minimum current value of the second current output range acquired from the input / output device 30 and the minimum current value of the second current output range acquired from the two-wire converter 50. FIG. 5 is a diagram showing an example of current setting in the low current mode. In FIG. 5, two current output ranges are illustrated: a current output range with a minimum value of 4 mA and a maximum value of 12 mA, and a current output range with a minimum current value of 3.6 mA and a maximum current value of 11 mA. In the example shown in FIG. 5, the current output range in which both the input / output device 30 and the two-wire converter 50 can operate is as follows. That is, on the minimum current value side, as a result of comparing the minimum current values of each of the two current output ranges, the larger minimum current value of 4 mA is selected. On the other hand, on the maximum current value side, as a result of comparing the maximum current values of each of the two current output ranges, the smaller maximum current value of 11 mA is selected. Further, in the case of mode 1, since digital communication is possible, the current output is fixed at the minimum current value of "4 mA" at which both can operate. Further, the setting unit 15 sets, as the supply voltage of mode 1, the supply voltage value obtained as the adjustment result by the voltage adjustment unit 13, i.e., the supply voltage value in response to which the OK flag is received. In addition, the setting unit 15 sets digital communication, for example, HART communication, as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including the current output, supply voltage, and transmission method of mode 1 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: Minimum current value of the second current output range (the larger of the two values) Supply voltage: Adjusted supply voltage value Transmission method: HART communication

[0053] (2) Setting of mode 2 Also, when the acquisition of the second current output range is successful from both the input / output device 30 and the two-wire converter 50, and there is no information on the minimum supply voltage value in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to mode 2. For example, the setting unit 15 sets the larger of the two minimum current values, i.e., the minimum current value of the second current output range acquired from the input / output device 30 and the minimum current value of the second current output range acquired from the two-wire converter 50, as the current output in mode 2. Further, in mode 2, since power adjustment by the voltage adjustment unit 13 is not performed, the setting unit 15 sets the standard supply voltage value, for example, 24V, as the supply voltage in mode 2. In addition, the setting unit 15 sets digital communication, for example, HART communication, as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including these current output, supply voltage, and transmission method in mode 2 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: Minimum current value of the second current output range (the larger of the two values) Supply voltage: Standard supply voltage value (24V) Transmission method: HART communication

[0054] (3) Setting of mode 3 Also, when the acquisition of the second current output range fails from one of the input / output device 30 and the two-wire converter 50, and there is information on the minimum supply voltage value in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to mode 3. For example, the setting unit 15 sets 4 mA, which is the minimum current value of the first current output range, i.e., the minimum current value of the instrumentation unified signal, as the current output in mode 3. Further, the setting unit 15 sets the supply voltage value obtained as the adjustment result by the voltage adjustment unit 13, i.e., the supply voltage value in response to which the OK flag is received, as the supply voltage in mode 3. In addition, the setting unit 15 sets digital communication, for example, HART communication, as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including these current output, supply voltage, and transmission method in mode 3 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: 4 mA Supply voltage: Adjusted supply voltage value Transmission method: HART communication

[0055] (4) Setting of Mode 4 Also, when the acquisition of the second current output range fails from one of the input / output device 30 and the two-wire converter 50, and the information on the minimum supply voltage value does not exist in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to Mode 4. For example, the setting unit 15 sets the minimum current value of the first current output range, that is, 4 mA which is the minimum current value of the instrumentation unified signal, as the current output of Mode 4. Further, in Mode 4, since the power adjustment by the voltage adjustment unit 13 is not performed, the setting unit 15 sets the standard supply voltage value, for example, 24 V, as the supply voltage of Mode 4. In addition, the setting unit 15 sets digital communication, for example, HART communication, as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including these current output, supply voltage, and transmission method of Mode 4 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: 4 mA Supply voltage: Standard supply voltage value (24 V) Transmission method: HART communication

[0056] In this way, in Modes 1 to 4, since both the input / output device 30 and the two-wire converter 50 have a digital communication function, a fixed value such as the minimum current value of the second current output range or 4 mA which is the minimum current value of the instrumentation unified signal is set as the current output. In this case, the measured value is transmitted from the two-wire converter 50 to the input / output device 30 by digital communication. Thereby, the power reduction effect can be enhanced compared with the case where analog communication using a current signal is performed.

[0057] As another aspect, when digital communication is not possible between the input / output device 30 and the two-wire converter 50, that is, in the manual mode, the setting unit 15 performs a manual setting of any one of the following modes 5 to 8. That is, the setting unit 15 performs an automatic setting of the following modes 5 to 8 based on an operation input as to whether a second current output range exists in both the input / output device 30 and the two-wire converter 50, and an operation input as to whether information on the minimum supply voltage value exists in a register or the like of the input / output device 30. Such operation inputs can be received via an operation unit provided in the input / output device 30 or the two-wire converter 50, or a calibration work device connectable to the input / output device 30 or the two-wire converter 50.

[0058] (5) Setting of Mode 5 For example, when the setting unit 15 receives an operation input in which a second current output range exists in both the input / output device 30 and the two-wire converter 50, and an operation input in which information on the minimum supply voltage value exists in the input / output device 30, the setting unit 15 sets the current output and the supply voltage corresponding to mode 5. For example, the setting unit 15 receives an operation input with a common range where two second current output ranges defined in the input / output device 30 and the two second current output ranges defined in the two-wire converter 50 overlap each other as the current output range in which both the input / output device 30 and the two-wire converter 50 can operate, and sets the received common range as the current output of mode 5. For example, in the example shown in FIG. 5, the two current output ranges of a 4 mA - 12 mA current output range and a 3.6 mA - 11 mA current output range overlap in the range of 4 mA - 11 mA as a result of comparing the minimum current value and the maximum current value. In this case, the common range of 4 mA - 11 mA is set as the current output of mode 5. Further, the setting unit 15 sets the supply voltage value obtained as a result of the adjustment by the voltage adjustment unit 13, that is, the supply voltage value in response to which the OK flag is received, as the supply voltage of mode 5. In addition, the setting unit 15 sets analog communication using a current signal as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including the current output, supply voltage, and transmission method of mode 5 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: Common range of two second current output ranges Supply voltage: Adjusted supply voltage value Transmission method: Analog communication

[0059] (6) Setting of mode 6 Also, when an operation input in which a second current output range exists in both the input / output device 30 and the two-wire converter 50, and an operation input in which information on the minimum supply voltage value does not exist in the input / output device 30 is received, the setting unit 15 sets a current output and a supply voltage corresponding to mode 6. For example, the setting unit 15 receives an operation input with a common range in which two second current output ranges defined in the input / output device 30 and the second current output range defined in the two-wire converter 50 overlap as a current output range in which both the input / output device 30 and the two-wire converter 50 can operate, and sets the received common range as the current output in mode 6. Further, in mode 6, since power adjustment by the voltage adjustment unit 13 is not performed, the setting unit 15 sets a standard supply voltage value, for example, 24V, as the supply voltage in mode 6. In addition, the setting unit 15 sets analog communication using a current signal as a transmission method between the input / output device 30 and the two-wire converter 50. Current-voltage settings including the current output, supply voltage, and transmission method in mode 6 are registered in respective registers of the input / output device 30 and the two-wire converter 50. Current output: Common range of two second current output ranges Supply voltage: Standard supply voltage value (24V) Transmission method: Analog communication

[0060] (7) Setting of mode 7 Also, when the setting unit 15 receives an operation input in which there is no second current output range in either the input / output device 30 or the two-wire converter 50, and an operation input in which information on the minimum supply voltage value exists in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to Mode 7. For example, the setting unit 15 sets the first current output range corresponding to the instrumentation unified signal, that is, 4 - 20 mA, as the current output in Mode 7. Further, the setting unit 15 sets the supply voltage value obtained as the adjustment result by the voltage adjustment unit 13, that is, the supply voltage value in response to which the OK flag is received, as the supply voltage in Mode 7. In addition, the setting unit 15 sets analog communication using a current signal as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including the current output, supply voltage, and transmission method in Mode 7 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: 4 - 20 mA Supply voltage: Adjusted supply voltage value Transmission method: Analog communication

[0061] (8) Setting of Mode 8 Also, when the setting unit 15 receives an operation input in which there is no second current output range in either the input / output device 30 or the two-wire converter 50, and an operation input in which information on the minimum supply voltage value does not exist in the input / output device 30, the setting unit 15 sets the current output and supply voltage corresponding to Mode 8. For example, the setting unit 15 sets the first current output range corresponding to the instrumentation unified signal, that is, 4 - 20 mA, as the current output in Mode 8. Further, in Mode 8, since the power adjustment by the voltage adjustment unit 13 is not performed, the setting unit 15 sets the standard supply voltage value, for example, 24 V, as the supply voltage in Mode 8. In addition, the setting unit 15 sets analog communication using a current signal as the transmission method between the input / output device 30 and the two-wire converter 50. The current-voltage settings including the current output, supply voltage, and transmission method in Mode 8 are registered in the respective registers of the input / output device 30 and the two-wire converter 50. Current output: 4 - 20 mA Supply voltage: Standard supply voltage value (24 V) Transmission method: Analog communication

[0062] The operation control unit 17 is a functional unit that controls the operations of the input / output device 30 or the two-wire converter 50. As one aspect, the operation control unit 17 executes operations such as current output, supply voltage, and transmission of the input / output device 30 or the two-wire converter 50 according to the current-voltage settings registered by the setting unit 15, that is, the settings of any one of modes 1 to 8.

[0063] <Specific examples of power reduction effects> Next, specific examples of power reduction effects for each mode will be described with reference to FIGS. 6 to 8. FIG. 6 is a diagram showing the power reduction effects for each mode. FIG. 7 is a schematic diagram showing an operation example of mode 8. FIG. 8 is a schematic diagram showing an operation example of mode 1.

[0064] In FIGS. 6 and 8, examples are shown in which the second current output ranges of modes 1, 2, 5, and 6 corresponding to the low current mode are 4 - 12 mA, but the minimum current value may be any value of 4 mA or less, and the maximum current value may be any value less than 20 mA as long as it exceeds the minimum current value. Further, in FIGS. 6 and 8, examples are shown in which the adjustment results of the supply voltage values of modes 1, 3, 5, and 7 corresponding to the low voltage mode are 19 V, but this is just an example and does not prevent the supply voltage value from being adjusted to less than 19 V. Note that in FIGS. 6 and 8, for the sake of convenience of explanation, an example in which the second power output range is unified to one type of 4 - 12 mA is given. Naturally, however, it does not prevent a plurality of different second power output ranges such as 4 - 12 mA and 3.6 - 12 mA from being held in each of the input / output device 30 and the two-wire converter 50.

[0065] Among these modes 1 to 8, in mode 8, a 4-20 mA current output range of the instrumentation unified signal is set, and a supply voltage value of 24 V, which is a standard, is set. In this way, mode 8 corresponds to a conventional operation example that does not fall into either the low current mode or the low voltage mode. In the case of mode 8, as shown in FIG. 7, a 24 V DC voltage is supplied from the input / output device 30 to the two-wire converter 50, so that the two-wire converter 50 operates with a 24 V DC voltage. Further, in the case of mode 8, the two-wire converter 50 converts the measured value of a physical quantity such as flow rate or differential pressure into a current value of 4-20 mA, which is the current output range of the instrumentation unified signal, and transmits the current value to the input / output device 30 via loop 3.

[0066] On the other hand, since modes 1 to 7 fall into either the low current mode or the low voltage mode, they correspond to the operation examples of the present embodiment. Taking the operation of mode 1 as an example among these modes 1 to 7. In the example of mode 1 shown in FIG. 8, the minimum current value of the second current output range stored in the registers of both the input / output device 30 and the two-wire converter 50, that is, a fixed value of 4 mA, is set for the current output. Further, in the case of mode 1 shown in FIG. 8, as a result of voltage adjustment between the input / output device 30 and the two-wire converter 50, a supply voltage value equal to the lowest supply voltage value, that is, 19 V, is set for the supply voltage. As a result, a 19 V DC voltage is supplied from the input / output device 30 to the two-wire converter 50, so that the two-wire converter 50 operates with a 19 V DC voltage. Further, the two-wire converter 50 transmits the measured value of a physical quantity such as flow rate or differential pressure to the input / output device 30 by digital communication.

[0067] Here, from the aspect of comparing the conventional operation example, that is, a 4-20 mA current output and a 24 V supply voltage, with the operation example of the present embodiment, FIG. 6 shows an example in which the maximum power consumption in mode 8 is used as a reference value, and the reduction value of the maximum power consumption is calculated by subtracting the maximum power consumption in each of modes 1 to 7 from the reference value, and the ratio of the reduction value to the reference value is derived as the power reduction effect.

[0068] As shown in Fig. 6, among Modes 1 to 7, the power reduction effects of Mode 1 and Mode 3 are the greatest, and a power reduction effect of -84% can be expected. Next, the power reduction effects of Mode 2 and Mode 4 are the next highest, and a power reduction effect of -80% can be expected. From the order of these modes, it can be seen that the power reduction effect of the mode in which the current output is fixed at one value, i.e., the minimum current value or 4 mA, and the measured value is transmitted by digital communication is higher than that of other modes.

[0069] <Process flow> Next, the process flow of the setting device 10 according to the present embodiment will be described. Figs. 9 and 10 are flowcharts showing the procedure of the setting process. This process can be started at the time of activation of the input / output device 30 and the two-wire converter 50 as an example only.

[0070] As shown in Fig. 9, the voltage adjustment unit 13 causes the input / output device 30 to supply a standard voltage value, for example, a DC voltage of 24 V, to the two-wire converter 50 (step S101).

[0071] Thereafter, when digital communication is possible between the input / output device 30 and the two-wire converter 50, that is, in the auto mode (step S102 Yes), the setting unit 15 executes automatic setting of any one of the above-mentioned Modes 1 to 4.

[0072] That is, when the acquisition of the second current output range is successful from both the input / output device 30 and the two-wire converter 50, and information on the minimum supply voltage value exists in the input / output device 30 (step S103 Yes and step S104 Yes), the voltage adjustment unit 13 executes a supply voltage adjustment process for adjusting the supply voltage between the input / output device 30 and the two-wire converter 50 (step S105). By such a supply voltage adjustment process, both the input / output device 30 and the two-wire converter 50 can operate, and the supply voltage value that becomes the lower limit is searched for. Then, the setting unit 15 sets the current output and the supply voltage corresponding to the above-mentioned Mode 1 (step S106).

[0073] Also, when the acquisition of the second current output range is successful from both the input / output device 30 and the two-wire converter 50, and information on the minimum supply voltage value does not exist in the input / output device 30 (step S103 Yes and step S104 No), the setting unit 15 sets the current output and supply voltage corresponding to the above mode 2 (step S107).

[0074] Also, when the acquisition of the second current output range fails from either the input / output device 30 or the two-wire converter 50, and information on the minimum supply voltage value exists in the input / output device 30 (step S103 No and step S108 Yes), the voltage adjustment unit 13 executes a supply voltage adjustment process for adjusting the supply voltage between the input / output device 30 and the two-wire converter 50 (step S105). By such a supply voltage adjustment process, both the input / output device 30 and the two-wire converter 50 can operate, and the supply voltage value that is the lower limit is searched for. Then, the setting unit 15 sets the current output and supply voltage corresponding to the above mode 3 (step S109).

[0075] Also, when the acquisition of the second current output range fails from either the input / output device 30 or the two-wire converter 50, and information on the minimum supply voltage value does not exist in the input / output device 30 (step S103 No and step S108 No), the setting unit 15 sets the current output and supply voltage corresponding to the above mode 4 (step S110).

[0076] On the other hand, when digital communication is not possible between the input / output device 30 and the two-wire converter 50, that is, in the manual mode (step S102 No), manual setting of any one of the above modes 5 to the above mode 8 is executed.

[0077] As shown in FIG. 10, when an operation input in which a second current output range exists in both the input / output device 30 and the two-wire converter 50, and an operation input in which information on the minimum supply voltage value exists in the input / output device 30 are received (step S111 is Yes and step S112 is Yes), the voltage adjustment unit 13 executes a supply voltage adjustment process for adjusting the supply voltage between the input / output device 30 and the two-wire converter 50 (step S105). By such a supply voltage adjustment process, both the input / output device 30 and the two-wire converter 50 can operate, and the supply voltage value that is the lower limit is searched for. Then, the setting unit 15 sets the current output and the supply voltage corresponding to the above-described mode 5 (step S113).

[0078] Also, when an operation input in which a second current output range exists in both the input / output device 30 and the two-wire converter 50, and an operation input in which information on the minimum supply voltage value does not exist in the input / output device 30 are received (step S111 is Yes and step S112 is No), the setting unit 15 sets the current output and the supply voltage corresponding to the above-described mode 6 (step S114).

[0079] Also, when an operation input in which a second current output range does not exist in one of the input / output device 30 and the two-wire converter 50, and an operation input in which information on the minimum supply voltage value exists in the input / output device 30 are received (step S111 is No and step S115 is Yes), the voltage adjustment unit 13 executes a supply voltage adjustment process for adjusting the supply voltage between the input / output device 30 and the two-wire converter 50 (step S105). By such a supply voltage adjustment process, both the input / output device 30 and the two-wire converter 50 can operate, and the supply voltage value that is the lower limit is searched for. Then, the setting unit 15 sets the current output and the supply voltage corresponding to the above-described mode 7 (step S116).

[0080] Also, when an operation input in which the second current output range does not exist in either the input / output device 30 or the two-wire converter 50, and an operation input in which information on the minimum supply voltage value does not exist in the input / output device 30 is received (No in step S111 and No in step S115), the setting unit 15 sets the current output and supply voltage corresponding to the above mode 8 (step S117).

[0081] <Summary of Embodiment 1> As described above, the setting device 10 according to the present embodiment sets the current output corresponding to either the standard mode or the low-current mode depending on whether the acquisition of the second current output range from the input / output device 30 and the two-wire converter 50 is successful. For this reason, when introducing the low-current mode, it is possible to operate both the input / output device 30 and the two-wire converter 50 normally, so the introduction of the low-current mode can be realized. Therefore, according to the setting device 10 according to the present embodiment, the low power consumption of the loop can be realized.

[0082] Furthermore, the setting device 10 according to the present embodiment executes an adjustment to lower the standard supply voltage value, that is, from 24V, between the input / output device 30 and the two-wire converter 50, and sets the adjusted supply voltage value as the supply voltage. For this reason, the introduction of the low-voltage mode can be realized. Therefore, according to the setting device 10 according to the present embodiment, the low power consumption of the loop can be realized.

[0083] <Embodiment 2> Next, a functional configuration example when the setting function described in the above Embodiment 1 is mounted on each of the input / output device 30 and the two-wire converter 50 will be described.

[0084] <Configuration of Input / Output Device 30> FIG. 11 is a block diagram showing a functional configuration example of the input / output device 30 and the converter 50. In FIG. 11, the blocks related to the setting function of the input / output device 30 are schematized, and the blocks related to the setting function of the converter 50 are schematized. Note that the solid lines connecting the blocks in FIG. 11 merely exemplify the relationships such as the causal relationship and the input / output relationship between the functions, and do not necessarily mean the connections between the physical components.

[0085] As shown in FIG. 11, the input / output device 30 includes a communication unit 31, a storage unit 32, a voltage adjustment unit 33, a reception unit 34, an inquiry unit 35A, a setting unit 35, and an operation control unit 37.

[0086] The communication unit 31 corresponds to the communication unit 11 shown in FIG. 1 and performs digital communication with the two-wire converter 50. Such digital communication may be realized, for example, by a hybrid communication method in which a digital signal is superimposed on an analog signal transmitted via loop 3, such as HART.

[0087] The storage unit 32 is a functional unit that stores various kinds of information. By way of example only, the storage unit 32 may be realized by a register, a cache, or the like. The storage unit 32 is not limited to the memory inside such a processor, and may be realized by other storage devices such as a main memory, a non-volatile memory, or a storage.

[0088] The voltage adjustment unit 33 corresponds to the voltage adjustment unit 13 shown in FIG. 1 and executes adjustment of the supply voltage from the input / output device 30 to the two-wire converter 50. As an example only, the voltage adjustment unit 33 supplies a standard voltage value, for example, a DC voltage of 24V, to the two-wire converter 50 when the input / output device 30 is started up. And when the minimum supply voltage value 32A is stored in the storage unit 32, the voltage adjustment unit 33 starts supplying a DC voltage corresponding to the minimum supply voltage value 32A. Thereafter, the voltage adjustment unit 33 searches for a supply voltage value at which both the input / output device 30 and the two-wire converter 50 can operate and which is the lower limit. Such adjustment of the supply voltage value may be realized, as an example only, by the above-described linear search. For example, the voltage adjustment unit 33 adds a predetermined voltage value to the previous supply voltage value to update the supply voltage value until an OK flag indicating that the supply voltage is OK is responded from the two-wire converter 50, and repeatedly performs a process of transmitting a supply voltage confirmation signal for confirming whether the two-wire converter 50 can operate with the supply of a DC voltage corresponding to the updated supply voltage value. Note that when the minimum supply voltage value 32A is not stored in the storage unit 32, since it is determined that the input / output device 30 can operate only with the standard supply voltage value, the adjustment of the supply voltage is not executed.

[0089] The receiving unit 34 is a processing unit that receives an analog current signal via loop 3. The current value received in this way is output to the operation control unit 37.

[0090] The inquiry unit 35A is a processing unit that inquires the two-wire converter 50 about the second current output range. As an example only, the inquiry unit 35A starts processing when a DC voltage corresponding to the standard supply voltage value is supplied at startup, or after voltage adjustment by the voltage adjustment unit 13. That is, the inquiry unit 35A transmits a current value confirmation signal including a request to inquire about the second current output range 32B stored in the storage unit 32 and the second current output range 52B stored in the storage unit 52 of the two-wire converter 50 to the two-wire converter 50 via the communication unit 31.

[0091] The setting unit 35 corresponds to the setting unit 15 shown in FIG. 1 and executes various settings in the input / output device 30, such as settings for current output, supply voltage, transmission method, and the like. Here, the setting unit 35 acquires the second current output range 32B stored in the storage unit 32 as the second current output range of the input / output device 30. On the other hand, the setting unit 35 acquires, as the second current output range of the two-wire converter 50, the second current output range 52B or no information included in the current value confirmation signal received as a response to the current value confirmation signal transmitted by the inquiry unit 35A. In addition, the settings for current output, supply voltage, and transmission method corresponding to any one of modes 1 to 8 are implemented with the same logic as the setting unit 15 shown in FIG. 1. Thereby, current / voltage settings 32C such as current output, supply voltage, and transmission method are registered in the storage unit 32.

[0092] The operation control unit 37 is a functional unit that controls the operation of the entire input / output device 30. As an example only, the operation control unit 37 executes operations corresponding to the current output, supply voltage, and transmission of the input / output device 30 according to the current / voltage settings 32C registered by the setting unit 35, that is, the settings of any one of modes 1 to 8.

[0093] As one aspect, when the current / voltage settings 32C are any one of modes 1 to 4, the operation control unit 37 receives the measured value of the physical quantity via digital communication by the communication unit 31.

[0094] As another aspect, when the current / voltage setting 32C is in any one of modes 5 to 8, the operation control unit 37 digitizes the current value received via the reception unit 34 based on the numerical range of the minimum current value and the maximum current value registered as the current / voltage setting 32C, and transmits it to the system 70. For example, when the low current mode is set, the operation control unit 37 performs scaling to assign the minimum current value of the current / voltage setting 32C to the minimum current value of the numerical range in the standard mode and assign the maximum current value of the current / voltage setting 32C to the maximum current value of the numerical range in the standard mode. For example, in the case of a 4-12 mA low current mode, when the operation control unit 37 receives a current value of 12 mA via the reception unit 34, it converts it to a current value of 20 mA and outputs the digital signal to the system 70.

[0095] By performing such scaling, on the system 70 side, the current value can be received on a 4-20 mA scale corresponding to the numerical range in the standard mode. Therefore, in the system 70, the current value received from the input / output device 30 can be converted into a process value of 0% to 100% without performing scaling between the low current mode and the standard mode. Accordingly, it is possible to eliminate the need for configuration changes on the hardware and software sides of the system 70.

[0096] <Configuration of the two-wire converter 50> As shown in FIG. 11, the two-wire converter 50 includes a communication unit 51, a storage unit 52, a voltage adjustment unit 53, a transmission unit 54, a response unit 55A, a setting unit 55, a measurement unit 56, and an operation control unit 57.

[0097] The communication unit 51 corresponds to the communication unit 11 shown in FIG. 1 and performs digital communication with the input / output device 30. Such digital communication may be realized, for example, by a hybrid communication method in which a digital signal is superimposed on an analog signal transmitted via the loop 3, such as HART.

[0098] The memory unit 52 is a functional unit that stores various types of information. As an example only, the memory unit 52 may be implemented by a register, a cache, or the like. The memory unit 52 is not limited to the internal memory of such a processor, and may be implemented by other storage devices such as a main memory, a non-volatile memory, or a storage.

[0099] The voltage adjustment unit 53 corresponds to the voltage adjustment unit 13 shown in FIG. 1 and executes adjustment of the supply voltage from the input / output device 30 to the two-wire converter 50. As an example only, the voltage adjustment unit 53 is activated when the supply of a standard voltage value, for example, a DC voltage of 24V, is started from the voltage adjustment unit 33 of the input / output device 30. At this time, the voltage adjustment unit 53 outputs a fixed maximum current value from the aspect of maximizing the voltage drop of the path. Thereafter, when supplying voltage from the input / output device 30 to the two-wire converter 50, the voltage adjustment unit 53 determines whether or not the voltage value of the arrival voltage reaching the two-wire converter 50 is equal to or greater than the minimum operating voltage 52A stored in the memory unit 52. At this time, if the voltage value of the arrival voltage to the two-wire converter 50 is equal to or greater than the minimum operating voltage 52A, it is determined that the two-wire converter 50 is operable. In this case, the voltage adjustment unit 53 responds to the input / output device 30 with an OK flag.

[0100] The transmission unit 54 is a processing unit that transmits an analog current signal via loop 3. As an example only, the transmission unit 54 generates a current value corresponding to the instruction at the timing corresponding to the instruction according to an instruction from the operation control unit 57.

[0101] The response unit 55A is a processing unit that responds to the input / output device 30 with the second current output range of the two-wire converter 50. As an example only, the response unit 55A starts processing when a DC voltage corresponding to the standard supply voltage value is supplied at startup, or after voltage adjustment by the voltage adjustment unit 13. That is, the response unit 55A receives a current value confirmation signal including a request to query the second current output range 32B of the input / output device 30 and the second current output range of the two-wire converter 50 via the communication unit 51. At this time, if the second current output range 52B is registered in the storage unit 52, the response unit 55A returns a current value response signal including the second current output range 52B. On the other hand, if there is no registration of the second current output range 52B in the storage unit 52, the response unit 55A returns a current value response signal indicating that there is no information on the second current output range 52B.

[0102] The setting unit 55 corresponds to the setting unit 15 shown in FIG. 1 and performs various settings in the two-wire converter 50, such as settings for current output, supply voltage, transmission method, etc. Here, the setting unit 55 acquires the second current output range 52B stored in the storage unit 52 as the second current output range of the two-wire converter 50. On the other hand, the setting unit 55 acquires the second current output range 32B or no information included in the current value confirmation signal received by the response unit 55A as the second current output range of the input / output device 30. In addition, the settings for current output, supply voltage, and transmission method corresponding to any of the modes 1 to 8 are implemented with the same logic as the setting unit 15 shown in FIG. 1. As a result, current / voltage settings 52C such as current output, supply voltage, and transmission method are registered in the storage unit 52.

[0103] The measurement unit 56 is a processing unit that measures physical quantities such as differential pressure, temperature, and flow rate. The measured values measured in this way are output to the operation control unit 57.

[0104] The operation control unit 57 is a functional unit that controls the operation of the two-wire converter 50 as a whole. As an example only, the operation control unit 57 executes operations corresponding to the current output, supply voltage, transmission, etc. of the two-wire converter 50 according to the current-voltage setting 52C registered by the setting unit 55, that is, the setting of any one of modes 1 to 8.

[0105] On one side, when the current-voltage setting 52C is any one of modes 1 to 4, the operation control unit 57 transmits the measurement value measured by the measurement unit 56 to the two-wire converter 50 via digital communication by the communication unit 51. On the other side, when the current-voltage setting 52C is any one of modes 5 to 8, the operation control unit 57 converts the measurement value measured by the measurement unit 56 into a current value based on the numerical range of the minimum current value and the maximum current value registered as the current-voltage setting 52C. The generation of the current value thus converted is instructed to the transmission unit 54.

[0106] <Sequence of operations> Next, the operations of the input / output device 30 and the two-wire converter 50 will be described. FIG. 12 is a sequence diagram showing the operations of the input / output device 30 and the two-wire converter 50. As shown in FIG. 12, the voltage adjustment unit 33 of the input / output device 30 supplies a standard voltage value, for example, a DC voltage of 24V, to the two-wire converter 50 at startup (step S301). The process of this step S301 corresponds to the process of step S101 shown in FIG. 9.

[0107] Subsequently, the inquiry unit 35A of the input / output device 30 transmits a current value confirmation signal including a request to inquire about the second current output range 32B stored in the storage unit 32 and the second current output range 52B stored in the storage unit 52 of the two-wire converter 50 to the two-wire converter 50 via the communication unit 31 (step S302).

[0108] When such a current value confirmation signal is received by the two-wire converter 50, the response unit 55A of the two-wire converter 50 returns a current value response signal including the second current output range 52B or no information of the second current output range 52B to the input / output device 30 (step S303).

[0109] The processes of steps S302 and S303 correspond to the process of step S104 shown in FIG. 9.

[0110] Then, the voltage adjustment unit 33 of the input / output device 30 executes the process of the following step S304. That is, in step S304, the voltage adjustment unit 33 of the input / output device 30 supplies a DC voltage corresponding to the minimum supply voltage value and starts transmitting a supply voltage confirmation signal for confirming whether the two-wire converter 50 is operable. Thereafter, the voltage adjustment unit 33 of the input / output device 30 searches for the supply voltage value at which both the input / output device 30 and the two-wire converter 50 are operable and which is the lower limit. Such adjustment of the supply voltage value may be realized by the above-mentioned linear search as an example. For example, until an OK flag is responded from the two-wire converter 50 in step S305, the voltage adjustment unit 33 adds a predetermined voltage value to the previous supply voltage value to update the supply voltage value, and repeatedly performs the process of transmitting a supply voltage confirmation signal for confirming whether the two-wire converter 50 is operable by supplying a DC voltage corresponding to the updated supply voltage value.

[0111] The processes of steps S304 and S305 correspond to the process of step S105 shown in FIG. 9.

[0112] When the adjustment of the supply voltage is completed in this way, each of the setting unit 35 of the input / output device 30 and the setting unit 55 of the two-wire converter 50 sets the current output, supply voltage, and transmission method corresponding to any one of modes 1 to 8 (steps S306A and S306B).

[0113] The processes of step S306A and step S306B are the same as the processes from step S104 to step S117 shown in FIGS. 9 and 10, so the description thereof will be omitted.

[0114] Note that, in FIG. 12, an example in which the supply voltage adjustment process executed in step S304 is realized by linear search is shown as an example only, but the present invention is not limited thereto, and other search methods, such as binary search, may be used to realize it without hindrance.

[0115] <Summary of Embodiment 2> As described above, the input / output device 30 and the two-wire converter 50 according to the present embodiment can realize the introduction of the low current mode and the introduction of the low voltage mode, similar to the above-described Embodiment 1. Therefore, according to the input / output device 30 and the two-wire converter 50 according to the present embodiment, low power consumption of the loop can be realized.

[0116] <Other Embodiments> Now, although the embodiments of the present invention have been described so far, the present invention can be applied in various ways, and furthermore, it may be implemented in various different forms other than the above-described embodiments.

[0117] <Scope of Application> In the above-described Embodiment 1 and the above-described Embodiment 2, the two-wire converter 50 is illustrated. However, of course, the connection method of the converter may not be limited to the two-wire type, and may be a three-wire type or a four-wire type.

[0118] FIG. 13 is a diagram showing an example of the applicable range of the low current mode and the low voltage mode. As shown in FIG. 13, the three-wire connection is different only in that the GND line is connected to both the converter 50 and the input / output device 30 compared to the two-wire type, and the power consumption of the entire loop 3 is the same as that of the two-wire type. Therefore, since the low current mode and the low voltage mode can also be applied to the three-wire type, the same effect as that of the two-wire type (see FIG. 6) can be obtained with respect to the power reduction effect.

[0119] In the four-wire connection, the signal output line 3 for the current value is also shared between the input / output device 30 and the converter 50, just like in the two-wire connection. Therefore, the low-current mode can also be applied to the four-wire connection. On the other hand, in the four-wire connection, since the 24V power supply to the converter 50 is supplied from the external power supply 40, a power supply line 5 is formed between the external power supply 40 and the converter 50. At this time, if the voltage of the external power supply 40 can be adjusted for each converter 50 to which the external power supply 40 is connected, the low-voltage mode (mode 5 or mode 7) in the manual mode can be applied. Furthermore, the greater the range in which the voltage of the external power supply 40 can be adjusted, that is, the greater the range in which it can be lowered from 24V, the more the supply voltage value can be lowered in the low-voltage mode. Note that if digital communication is possible between the external power supply 40 and the converter 50, the low-voltage mode (mode 1 or mode 3) in the auto mode can also be applied.

[0120] <Numerical values, etc.> The matters described in the above embodiments, such as specific examples like the number of two-wire converters 50 and the types of physical quantities to be measured, are merely examples and can be changed. Also, the flowcharts described in the embodiments can have their processing order changed within a non-contradictory range.

[0121] <System> Regarding the processing procedures, control procedures, specific names, and information including various data and parameters shown in the above documents and drawings, they can be arbitrarily changed unless otherwise specified. For example, one or more of the functional units among the communication unit 11, voltage adjustment unit 13, setting unit 15, and operation control unit 17 may be configured by separate devices.

[0122] Also, each component of each device shown is a functional concept and does not necessarily have to be physically configured as shown in the figure. That is, the specific forms of dispersion and integration of each device are not limited to those shown. In other words, all or part of it can be functionally or physically dispersed and integrated in any unit according to various loads and usage situations, etc. Note that each configuration may be a physical configuration.

[0123] Furthermore, all or any part of each processing function performed by each device can be implemented by a CPU (Central Processing Unit) and a program analyzed and executed by the CPU, or can be implemented as hardware by wired logic.

[0124] <Hardware> Next, a hardware configuration example of the computer described in the embodiment will be described. FIG. 14 is a diagram showing a hardware configuration example. As shown in FIG. 14, the setting device 100 includes a communication device 100a, a storage device 100b, a memory 100c, and a processor 100d. Note that each part shown in FIG. 14 is mutually connected by a bus or the like.

[0125] The communication device 100a is a HART modem or the like that superimposes a digital signal on an analog signal transmitted and received via Loop 3. The storage device 100b is a ROM, an HDD, or the like, and stores a program for operating the functions shown in FIG. 1 and data referred to by the program.

[0126] The processor 100d reads out a program for executing the same processing as the processing unit shown in FIG. 1 from the storage device 100b or the like and expands it in the memory 100c, thereby operating a process for executing the functions described in FIGS. 9 to 10 and the like. For example, this process executes the same functions as the processing unit included in the setting device 10 shown in FIG. 1. Specifically, the processor 100d reads out a program having the same functions as the communication unit 11, the voltage adjustment unit 13, the setting unit 15, the operation control unit 17, and the like from the storage device 100b or the like. Then, the processor 100d executes a process for executing the same processing as the communication unit 11, the voltage adjustment unit 13, the setting unit 15, the operation control unit 17, and the like.

[0127] In this way, the setting device 100 operates as a setting device that executes the setting method by reading and executing a program. Further, the setting device 100 can also realize the same functions as those of the above-described embodiments by reading the program from the recording medium by the medium reading device and executing the read program. Note that the program in other embodiments is not limited to being executed by the setting device 100. For example, the present invention can be similarly applied when another computer or server executes the program, or when these cooperate to execute the program.

[0128] The above program can be distributed via a network such as the Internet. Further, the above program can be recorded on an arbitrary recording medium and executed by being read from the recording medium by a computer. For example, the recording medium can be realized by a hard disk, a flexible disk (FD), a CD-ROM, an MO (Magneto-Optical disk), a DVD (Digital Versatile Disc), or the like.

[0129] <Others> Some examples of combinations of the disclosed technical features are described below.

[0130] (1) A current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, the communication unit executing communication to obtain a second current output range in which the minimum current value or the maximum current value is smaller than that of a first current output range, a setting unit that sets a current output corresponding to either the first current output range or the second current output range based on whether the acquisition of the second current output range is successful; A setting device characterized by comprising:

[0131] (2) When the acquisition of the second current output range is successful, the setting unit sets, as the current output of the transmission signal, the larger one of the two minimum current values, namely, the minimum current value of the second current output range acquired from the input / output device and the minimum current value of the second current output range acquired from the converter. The setting device according to (1) is characterized in that.

[0132] (3) When the acquisition of the second current output range fails, the setting unit sets, as the current output of the transmission signal, the minimum current value of the first current output range. The setting device according to (1) or (2) is characterized in that.

[0133] (4) When the communication fails and the acquisition of the second current output range fails, the setting unit accepts an operation input for a common range in which the two second current output ranges, namely, the second current output range defined in the input / output device and the second current output range defined in the converter, overlap with each other, and sets, as the current output of the transmission signal, the common range for which the operation input has been accepted. The setting device according to any one of (1) to (3) is characterized in that.

[0134] (5) The setting device according to (4) further includes a conversion unit that converts the current value of the transmission signal into a process value based on the minimum current value and the maximum current value of the second current output range set by the setting unit.

[0135] (6) The setting device further includes a voltage adjustment unit that executes an adjustment to lower the supply voltage supplied from the input / output device to the converter via the loop to a value equal to or lower than a standard supply voltage value and to a lower limit value at which the input / output device and the converter can operate. The setting unit sets, as the supply voltage, the lower limit value of the supply voltage adjusted by the voltage adjustment unit. The setting device according to any one of (1) to (5) is characterized in that.

[0136] (7) The voltage adjustment unit searches for the lower limit value at which the input / output device and the converter can operate by linear search or binary search. The setting device according to (6) is characterized in that.

[0137] (8) The setting device according to any one of (1) to (7), wherein the first current output range is 4 - 20 mA.

[0138] (9) The setting device according to any one of (1) to (8), wherein the communication is HART (Highway Addressable Remote Transducer).

[0139] (10) A current output range of a transmission signal through a loop formed between a transducer that converts a physical quantity into a current value and an input / output device that outputs the current value input from the transducer to a system, and performs communication to obtain a second current output range in which the minimum current value or the maximum current value is smaller than that of the first current output range, Based on whether the acquisition of the second current output range is successful, set a current output corresponding to either the first current output range or the second current output range, A setting method characterized in that a processor executes the process.

[0140] (11) A current output range of a transmission signal through a loop formed between a transducer that converts a physical quantity into a current value and an input / output device that outputs the current value input from the transducer to a system, and performs communication to obtain a second current output range in which the minimum current value or the maximum current value is smaller than that of the first current output range, Based on whether the acquisition of the second current output range is successful, set a current output corresponding to either the first current output range or the second current output range, A setting program characterized by causing a processor to execute the process.

Explanation of Signs

[0141] 10 Setting device 11 Communication unit 13 Voltage adjustment unit 15 Setting unit 17 Operation control unit 30 Input / output device 31 Communication unit 32 Memory unit 32A Minimum supply voltage value 32B Second current output range 32C Current-voltage setting 33 Voltage adjustment unit 34 Receiver 35A Inquiry unit 35 Setting unit 37 Operation control unit 50 Two-wire converter 51 Communication unit 52 Memory unit 52A Minimum operating voltage 52B Second current output range 52C Current-voltage setting 53 Voltage adjustment unit 54 Transmission unit 55A Response unit 55 Setting unit 56 Measurement unit 57 Operation control unit 70 System

Claims

1. A current output range of a transmission signal via a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, the communication unit executes communication to obtain a second current output range in which the minimum current value or the maximum current value is smaller than that of a first current output range, a setting unit that sets a current output corresponding to either the first current output range or the second current output range based on whether the acquisition of the second current output range is successful; A setting device, characterized by comprising the above.

2. The setting unit, when the acquisition of the second current output range is successful, sets, as the current output of the transmission signal, the larger of the two minimum current values, namely, the minimum current value of the second current output range acquired from the input / output device and the minimum current value of the second current output range acquired from the converter. The setting device according to claim 1, characterized by the above.

3. The setting unit, when the acquisition of the second current output range fails, sets the minimum current value of the first current output range as the current output of the transmission signal. The setting device according to claim 1, characterized by the above.

4. The setting unit, when the communication fails and the acquisition of the second current output range fails, accepts an operation input for a common range in which two second current output ranges, namely, the second current output range defined in the input / output device and the second current output range defined in the converter, overlap with each other, and sets the common range that has accepted the operation input as the current output of the transmission signal. The setting device according to claim 1, characterized by the above.

5. The setting device according to claim 4, further comprising a conversion unit that converts the current value of the transmission signal into a process value based on the minimum current value and the maximum current value of the second current output range set by the setting unit.

6. further comprising a voltage adjustment unit that executes an adjustment to lower the supply voltage supplied from the input / output device to the converter via the loop to a value equal to or lower than a standard supply voltage value and to a lower limit value at which the input / output device and the converter can operate, The setting unit sets the lower limit value of the supply voltage adjusted by the voltage adjustment unit as the supply voltage. The setting device according to claim 1, characterized by the above.

7. The setting device according to claim 6, wherein the voltage adjustment unit searches for a lower limit value at which the input / output device and the converter can operate by linear search or binary search.

8. The setting device according to claim 1, wherein the first current output range is 4 - 20 mA.

9. The setting device according to claim 1, wherein the communication is HART (Highway Addressable Remote Transducer).

10. A current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, the method comprising: performing communication to obtain a second current output range in which a minimum current value or a maximum current value is smaller than that of a first current output range; setting a current output corresponding to either the first current output range or the second current output range based on whether the acquisition of the second current output range is successful; A setting method, wherein a processor executes the process.

11. A current output range of a transmission signal through a loop formed between a converter that converts a physical quantity into a current value and an input / output device that outputs the current value input from the converter to a system, the method comprising: performing communication to obtain a second current output range in which a minimum current value or a maximum current value is smaller than that of a first current output range; setting a current output corresponding to either the first current output range or the second current output range based on whether the acquisition of the second current output range is successful; A setting program, wherein the processor is caused to execute the process.

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