WO2018179372A1 - アナログ入力ユニット及び基準電圧安定化回路 - Google Patents

アナログ入力ユニット及び基準電圧安定化回路 Download PDF

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Publication number
WO2018179372A1
WO2018179372A1 PCT/JP2017/013706 JP2017013706W WO2018179372A1 WO 2018179372 A1 WO2018179372 A1 WO 2018179372A1 JP 2017013706 W JP2017013706 W JP 2017013706W WO 2018179372 A1 WO2018179372 A1 WO 2018179372A1
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WO
WIPO (PCT)
Prior art keywords
resistor
analog
reference voltage
input unit
current
Prior art date
Application number
PCT/JP2017/013706
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English (en)
French (fr)
Japanese (ja)
Inventor
有記浩 奥田
健太 渡邉
圭治 二宮
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2018507042A priority Critical patent/JP6342100B1/ja
Priority to CN201780079904.XA priority patent/CN110114638B/zh
Priority to PCT/JP2017/013706 priority patent/WO2018179372A1/ja
Publication of WO2018179372A1 publication Critical patent/WO2018179372A1/ja

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements

Definitions

  • the present invention provides an analog input unit that can be connected to a resistance temperature detector, connected to a current output sensor, and connected to a voltage output sensor by a switch, and can be applied to the analog input unit.
  • the present invention relates to a reference voltage stabilization circuit.
  • the sensor connected to the input terminal of the analog input unit includes a resistance temperature detector that detects temperature, a current output sensor that detects physical quantities such as pressure and flow rate, or a voltage output sensor.
  • a resistance temperature detector that detects temperature
  • a current output sensor that detects physical quantities such as pressure and flow rate
  • a voltage output sensor Conventionally, there is an analog input unit that can connect these sensors and can selectively connect various sensors to input terminals by incorporating a circuit that executes input processing according to the sensor input specifications. (For example, the following patent document 1).
  • AD Analog-to-Digital
  • Patent Documents 1 and 2 when an input is selected by switching an internal switch according to a connected sensor, a leakage current is generated in a circuit not selected through the switch. It will flow. Due to this leakage current, there is a problem that a current necessary for a circuit that should flow originally is not supplied.
  • the reference voltage is generated by passing a current through the reference resistor.
  • the current that should originally flow is reduced by the leakage current.
  • the reference voltage varies.
  • the resolution and accuracy required for AD conversion are reduced. From the above viewpoint, when a sensor that needs to generate a reference voltage is connected to an analog input unit, a mechanism for keeping the reference voltage constant with high accuracy is required.
  • the present invention has been made in view of the above, and even when a sensor is connected to an analog input unit that needs to generate a reference voltage, a reference caused by a leak current that can occur when switching the sensor input
  • An object of the present invention is to provide a reference voltage stabilization circuit capable of reducing voltage fluctuation.
  • an analog input unit includes an input terminal that can input an analog value from an analog sensor, a switch that enables selection or non-selection of the analog sensor, and selection
  • An AD converter that converts an analog value from the analog sensor into a digital value, a reference resistor that generates a reference voltage that is referenced by the AD converter, and a reference voltage stabilization circuit that is connected in parallel to the reference resistor.
  • FIG. 1 The figure which shows the structure of the input process part in the analog input unit which concerns on embodiment
  • the figure which shows the state by which the three-wire type resistance thermometer was connected to the analog input unit shown in FIG. 1 is a circuit diagram showing the internal configuration of the reference voltage stabilization circuit shown in FIGS.
  • FIG. 1 is a diagram illustrating a configuration of an input processing unit in the analog input unit according to the embodiment.
  • an analog input unit 1 includes input terminals 2, 3, 4, and 5 used for at least one of a three-wire resistance thermometer, a voltage output sensor, and a current output sensor. More specifically, the input terminals 2 and 3 are voltage input terminals for a three-wire resistance thermometer.
  • the input terminal 4 is a current input terminal for the three-wire resistance thermometer, and is also used as a voltage input terminal for the voltage output sensor and a current input terminal for the current output sensor.
  • the input terminal 5 is a voltage input terminal of the voltage output sensor and a current input terminal of the current output sensor.
  • thermometer voltage output sensor
  • current output sensor current output sensor
  • input terminals 2, 3, 4, and 5 are examples, and any terminals may be used as long as at least one of the voltage value and the current value can be input.
  • the analog input unit 1 can select or deselect an AD converter 6 that converts an input analog value into a digital value, a reference resistor 7 that generates a reference voltage referenced by the AD converter 6, and an analog sensor.
  • the switches 8 and 9 are further provided. More specifically, the switch 8 selects an input of a current supplied from the three-wire temperature measuring resistor, an applied voltage from the voltage output sensor, or a supply current from the current output sensor.
  • the switch 9 selects an input of an applied voltage from the voltage output sensor or a supply current from the current output sensor.
  • the analog input unit 1 further includes a reference voltage stabilization circuit 10 that suppresses fluctuations in the reference voltage generated by the reference resistor 7 and a current-voltage conversion resistor 11.
  • a reference voltage stabilization circuit 10 that suppresses fluctuations in the reference voltage generated by the reference resistor 7 and a current-voltage conversion resistor 11.
  • the resistance value of the reference resistor 7 is R ref
  • the resistance value of the current-voltage conversion resistor 11 is R.
  • FIG. 2 is a diagram showing a state where the voltage output sensor 12 is connected to the analog input unit 1 shown in FIG. As shown in FIG. 2, the voltage output sensor 12 is connected between the input terminal 4 and the input terminal 5.
  • the switch 8 is controlled to be turned off by software inside the analog input unit 1.
  • the switch 9 is switched to a side where the voltage applied from the input terminal 4 can be directly input to the AD converter 6 by software inside the analog input unit 1.
  • the voltage applied from the input terminal 4 is input to the AD converter 6 via the switch 9, and the AD converter 6 measures the potential difference between the input terminal 4 and the input terminal 5.
  • FIG. 3 is a diagram showing a state where the current output sensor 13 is connected to the analog input unit 1 shown in FIG.
  • the current output sensor 13 is connected between the input terminal 4 and the input terminal 5.
  • the switch 8 is controlled to be turned off by software inside the analog input unit 1.
  • the switch 9 is switched to the side where the current supplied from the input terminal 4 flows to the current-voltage conversion resistor 11 by software inside the analog input unit 1.
  • the current is converted into a voltage by the current-voltage conversion resistor 11. That is, the current supplied from the input terminal 4 flows to the current-voltage conversion resistor 11 via the switch 9, and the current value is converted into a voltage value in the current-voltage conversion resistor 11.
  • the voltage generated at both ends of the current-voltage conversion resistor 11 is measured by the AD converter 6, and the current value of the current supplied from the input terminal 4 is calculated by the AD converter 6.
  • FIG. 4 is a diagram showing a state in which a three-wire resistance thermometer 14 is connected to the analog input unit 1 shown in FIG.
  • the three-wire resistance thermometer 14 is connected to the input terminals 2, 3, and 4.
  • the switch 8 is turned on by software inside the analog input unit 1.
  • the switch 9 is controlled to be turned off by software inside the analog input unit 1.
  • the input terminals 2 and 3 operate as voltage input terminals and current input terminals.
  • a constant current I is supplied from the AD converter 6 toward the three-wire temperature measuring resistor 14.
  • the current 2I directed from the input terminals 2 and 3 to the three-wire temperature measuring resistor 14 flows into the reference resistor 7 via the input terminal 4 and the switch 8, and generates the reference voltage R ref ⁇ 2I.
  • a part of the current 2I flows to the switch 9 as the leakage current I leak .
  • the current 2I flowing into the reference resistor 7 is reduced by the amount of the leakage current I leak .
  • the reference voltage decreases by R ref ⁇ I leak .
  • the reference voltage stabilization circuit 10 is connected to the reference resistor 7 in parallel. With this connection, the reference voltage stabilization circuit 10 can detect a decrease in the reference voltage.
  • the reference voltage stabilizing circuit 10 detects R ref ⁇ I leak that is a reduced voltage component from the voltage of the reference resistor 7, and generates a compensation current I comp that is the same as the leakage current I leak from the detected voltage. Returning the compensation current I comp to the reference resistor 7 cancels out the leakage current I leak which is a decrease of the current 2I.
  • FIG. 5 is a circuit diagram showing an internal configuration of the reference voltage stabilizing circuit 10 shown in FIGS.
  • a resistor 16 which is a first resistor, is connected between the output terminal of the operational amplifier 15 and a positive terminal (+ side) on the input side of the operational amplifier 15.
  • a resistor 17, which is a second resistor is connected between the negative terminal and the negative terminal ( ⁇ ) terminal of the reference voltage stabilizing circuit 10, and the output terminal of the operational amplifier 15 and the input side of the operational amplifier 15.
  • a resistor 18, which is a third resistor, is connected between the negative terminal ( ⁇ side) of the terminal.
  • the positive side (+ side) terminal of the reference voltage stabilizing circuit 10 is connected to the reference voltage input terminal 20 of the AD converter 6 to which the reference resistor 7 is connected as shown in FIG.
  • the voltage of the reference resistor 7 is V ref .
  • the resistance value R 2 of the resistor 17 and the resistance R 3 of the resistor 18 is set to the same value, the relational expression is obtained.
  • V ref ⁇ R 1 ⁇ I comp (1)
  • R 1 is the resistance value of the resistor 16
  • the reference voltage stabilizing circuit 10 is given a function of positive current feedback by the resistor and the operational amplifier. By providing the reference voltage stabilization circuit 10 having this function, the current flowing through the reference resistor 7 can be made constant, and the reference voltage V ref can be maintained with high accuracy.
  • the resistance value R 2 and the resistance value R 3 may be regarded as the same value.
  • the above equation (1) means that the error of the reference voltage V ref can be reduced by selecting the resistance value R 1 of the resistor 16. That is, if the method of the present embodiment is used, the error of the reference voltage V ref can be reduced regardless of the resistance value R ref of the reference resistor 7.
  • the reference voltage stabilization circuit 10 can be externally attached to an external terminal of the analog input unit 1. . According to this configuration, the reference voltage stabilization circuit 10 may be retrofitted when needed, and it is not necessary to incorporate the reference voltage stabilization circuit 10, thereby suppressing an increase in cost of the analog input unit 1. Is possible.
  • the reference voltage stabilizing circuit 10 is connected to the outside of the AD converter 6, but may be built in the AD converter 6.
  • the analog input unit 1 can be downsized by making an IC together with the AD converter 6.
  • thermometer a case where a three-wire resistance thermometer is used has been described as an example, but the present invention can also be applied to a two-wire resistance thermometer or a four-wire resistance thermometer.
  • 1 analog input unit 2, 3, 4, 5 input terminal, 6 AD converter, 7 reference resistor, 8, 9 switch, 10 reference voltage stabilization circuit, 11 current voltage conversion resistor, 12 voltage output sensor, 13 current output Sensor, 14 3-wire resistance thermometer, 15 operational amplifier, 16, 17, 18 resistance, 20 reference voltage input terminal.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Analogue/Digital Conversion (AREA)
  • Testing Or Calibration Of Command Recording Devices (AREA)
  • Measurement Of Current Or Voltage (AREA)
PCT/JP2017/013706 2017-03-31 2017-03-31 アナログ入力ユニット及び基準電圧安定化回路 WO2018179372A1 (ja)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2018507042A JP6342100B1 (ja) 2017-03-31 2017-03-31 アナログ入力ユニット及び基準電圧安定化回路
CN201780079904.XA CN110114638B (zh) 2017-03-31 2017-03-31 模拟输入单元以及基准电压稳定化电路
PCT/JP2017/013706 WO2018179372A1 (ja) 2017-03-31 2017-03-31 アナログ入力ユニット及び基準電圧安定化回路

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Application Number Priority Date Filing Date Title
PCT/JP2017/013706 WO2018179372A1 (ja) 2017-03-31 2017-03-31 アナログ入力ユニット及び基準電圧安定化回路

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Cited By (1)

* Cited by examiner, † Cited by third party
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KR102253854B1 (ko) * 2020-12-06 2021-05-20 주식회사 알에스팀 범용 IoT 안전관제 방법

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CN110554241B (zh) * 2019-10-08 2020-11-27 哈尔滨市科佳通用机电股份有限公司 机车信号接收线圈绝缘电阻在车测试方法及装置
CN113203502B (zh) * 2021-04-19 2024-05-31 杭州电子科技大学 一种适用于量产的高精度温度检测装置及其量产方法

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JPH085675A (ja) * 1994-06-16 1996-01-12 Sony Tektronix Corp 電圧電流測定器の入力回路
JPH11134588A (ja) * 1997-10-29 1999-05-21 Hitachi Ltd アナログ入力装置
JP2008304203A (ja) * 2007-06-05 2008-12-18 Omron Corp アナログ入力モジュールおよび機器

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JP2009217809A (ja) * 2008-02-12 2009-09-24 Seiko Epson Corp 基準電圧生成回路、集積回路装置および信号処理装置
CN201748983U (zh) * 2010-06-21 2011-02-16 江苏安科瑞电器制造有限公司 综合信号智能温度变送器
CN101872193B (zh) * 2010-06-23 2012-05-02 鞍山永恒自控仪表有限公司 基于现场总线的多功能测控模块
CN105547341B (zh) * 2014-10-31 2018-07-27 南京河海南自水电自动化有限公司 一种测量五线制差动电阻式传感器的装置和方法
CN205861232U (zh) * 2016-07-26 2017-01-04 高准有限公司 温度测量电路及变送器

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JPH085675A (ja) * 1994-06-16 1996-01-12 Sony Tektronix Corp 電圧電流測定器の入力回路
JPH11134588A (ja) * 1997-10-29 1999-05-21 Hitachi Ltd アナログ入力装置
JP2008304203A (ja) * 2007-06-05 2008-12-18 Omron Corp アナログ入力モジュールおよび機器

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102253854B1 (ko) * 2020-12-06 2021-05-20 주식회사 알에스팀 범용 IoT 안전관제 방법

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CN110114638B (zh) 2020-08-28
CN110114638A (zh) 2019-08-09
JP6342100B1 (ja) 2018-06-13
JPWO2018179372A1 (ja) 2019-04-11

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