JP3517870B2 - Two-wire signal transmitter - Google Patents
Two-wire signal transmitterInfo
- Publication number
- JP3517870B2 JP3517870B2 JP28085798A JP28085798A JP3517870B2 JP 3517870 B2 JP3517870 B2 JP 3517870B2 JP 28085798 A JP28085798 A JP 28085798A JP 28085798 A JP28085798 A JP 28085798A JP 3517870 B2 JP3517870 B2 JP 3517870B2
- Authority
- JP
- Japan
- Prior art keywords
- converter
- side circuit
- signal
- transmission line
- wire
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Fee Related
Links
Landscapes
- Arrangements For Transmission Of Measured Signals (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、センサで測定した
物理量を電気信号に変換し、この電気信号を２本の伝送
線を介して負荷側に伝送する二線式信号伝送器に関する
ものである。更に詳しくは、伝送器の内部にある不揮発
性メモリにデータを書き込む際に消費電流を低減するた
めの工夫に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wire type signal transmitter for converting a physical quantity measured by a sensor into an electric signal and transmitting the electric signal to a load side through two transmission lines. . More specifically, the present invention relates to a device for reducing current consumption when writing data in a non-volatile memory inside a transmitter.
【０００２】[0002]
【従来の技術】図３は従来における二線式信号の構成例
を示した図である。図３で、二線式信号伝送器１０は、
２本の伝送線３１，３２を介して電気信号を負荷側に伝
送する。負荷側には、例えばディストリビュータ４０が
ある。ディストリビュータ４０は、送られてきた電気信
号を絶縁伝送する。絶縁伝送された信号は、例えばＡ／
Ｄ変換（アナログ／デジタル変換）してコンピュータ
（図示せず）に渡される。通信端末５０は伝送線に接続
されていて二線式信号伝送器１０と通信を行う。2. Description of the Related Art FIG. 3 is a diagram showing a configuration example of a conventional two-wire system signal. In FIG. 3, the two-wire signal transmitter 10 is
An electric signal is transmitted to the load side via the two transmission lines 31 and 32. On the load side, there is a distributor 40, for example. The distributor 40 insulatedly transmits the sent electric signal. The signal transmitted through insulation is, for example, A /
It is D-converted (analog / digital conversion) and passed to a computer (not shown). The communication terminal 50 is connected to the transmission line and communicates with the two-wire signal transmitter 10.
【０００３】二線式信号伝送器１０は、センサの測定入
力を取り込む入力側回路１１と、取り込んだ測定入力を
所定の形式の電気信号に変換して伝送線に送出する出力
側回路１２とからなる。入力側回路１１で、マルチプレ
クサ１１１はセンサの測定入力Ｓ１，Ｓ２，Ｓ３のいず
れかを選択する。Ａ／Ｄ変換器１１２はマルチプレクサ
１１１で選択した測定入力をデジタルデータに変換す
る。変換したデジタルデータをフォトカップラＰＣ１は
出力側回路１２に絶縁伝送する。ＤＣ／ＤＣ変換器ＣＯ
Ｎは、出力側回路１２にある電源の電力を入力側回路１
１に供給する。電源電圧はラインＬ１からとっている。The two-wire type signal transmitter 10 comprises an input side circuit 11 for taking in a measurement input of a sensor and an output side circuit 12 for converting the taken in measurement input into an electric signal of a predetermined format and sending it out to a transmission line. Become. In the input side circuit 11, the multiplexer 111 selects one of the sensor measurement inputs S1, S2 and S3. The A / D converter 112 converts the measurement input selected by the multiplexer 111 into digital data. The photocoupler PC1 insulatedly transmits the converted digital data to the output side circuit 12. DC / DC converter CO
N is the electric power of the power supply in the output side circuit 12
Supply to 1. The power supply voltage is taken from the line L1.
【０００４】出力回路１２で、演算制御部１２１は、フ
ォトカップラＰＣ１で伝送されたデジタルデータを読み
込んで必要な演算を行い、出力データとして出力電流制
御部１２２に送る。出力電流制御部１２２は、トランジ
スタＱ１を制御して出力データを所定の形式の電気信
号、例えば４〜２０ｍＡの電流信号に変換し、端子１２
３，１２４を介して伝送線３１，３２に送出する。In the output circuit 12, the arithmetic control unit 121 reads the digital data transmitted by the photocoupler PC1 and performs a necessary arithmetic operation, and sends it as output data to the output current control unit 122. The output current controller 122 controls the transistor Q1 to convert the output data into an electric signal of a predetermined format, for example, a current signal of 4 to 20 mA, and the terminal 12
It is sent to the transmission lines 31 and 32 via 3,124.
【０００５】演算制御部１２１は出力電流制御部１２２
に内蔵された通信インタフェイス回路（図示せず）によ
って出力（４〜２０ｍＡの電流信号）に通信データを重
畳して通信端末５０と通信を行う。演算制御部１２１と
出力電流制御部１２２は、例えばマイクロコンピュータ
で構成されている。不揮発性メモリ１２５には演算制御
部１２１が接続されていて、通信端末５０から動作モー
ドや補正係数などのデータを書き込むことができる。動
作モードとしては、例えば、熱電対、測温抵抗体等のセ
ンサの種類がある。補正係数としては、例えば、校正を
行うときに用いる係数がある。不揮発性メモリ１２５と
しては、例えばＥＥＰＲＯＭが用いられる。The arithmetic control unit 121 is an output current control unit 122.
A communication interface circuit (not shown) built in the device superimposes communication data on the output (current signal of 4 to 20 mA) to communicate with the communication terminal 50. The arithmetic control unit 121 and the output current control unit 122 are composed of, for example, a microcomputer. The arithmetic control unit 121 is connected to the non-volatile memory 125, and data such as an operation mode and a correction coefficient can be written from the communication terminal 50. The operation modes include, for example, types of sensors such as thermocouples and resistance temperature detectors. As the correction coefficient, for example, there is a coefficient used when performing calibration. An EEPROM, for example, is used as the non-volatile memory 125.
【０００６】図３の二線式信号伝送器で、例えば、温度
センサの測定温度０℃〜１００℃を伝送器の出力４〜２
０ｍＡに対応させるものとする。測定温度が０℃のとき
は、伝送器に許容される消費電流は最大４ｍＡで、余裕
を持たせるために３．２ｍＡ程度の電流で伝送器が動作
しなければならない。しかし、ＥＥＰＲＯＭ等の不揮発
性メモリは書込み時の消費電流が大きいため、書込み時
に伝送器の許容消費電流である４ｍＡを超えてしまうこ
とがあるという問題点があった。In the two-wire type signal transmitter of FIG. 3, for example, when the measured temperature of the temperature sensor is 0 ° C to 100 ° C, the output of the transmitter is 4 to 2
It shall correspond to 0 mA. When the measurement temperature is 0 ° C., the maximum current consumption allowed for the transmitter is 4 mA, and the transmitter must operate with a current of about 3.2 mA in order to have a margin. However, since a non-volatile memory such as an EEPROM consumes a large amount of current when writing, there is a problem that the allowable current consumption of the transmitter at the time of writing may exceed 4 mA.
【０００７】[0007]
【発明が解決しようとする課題】本発明は上述した問題
点を解決するためになされたものであり、不揮発性メモ
リの書込み時にだけＤＣ／ＤＣ変換器を停止することに
よって、伝送器の動作に余裕を持たせ、回路設計の自由
度を上げることができる二線式信号伝送器を実現するこ
とを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the operation of the transmitter is improved by stopping the DC / DC converter only when writing to the nonvolatile memory. It is an object of the present invention to realize a two-wire type signal transmitter that has a margin and can increase the degree of freedom in circuit design.
【０００８】[0008]
【課題を解決するための手段】本発明は次のとおりの構
成になった二線式信号伝送器である。The present invention is a two-wire signal transmitter having the following configuration.
【０００９】（１）センサで測定した物理量を電気信号
に変換し、この電気信号を２本の伝送線を介して負荷側
に伝送する二線式信号伝送器において、伝送線上の電気
信号に重畳されたデータが書き込まれる不揮発性メモリ
と、センサの測定入力を取り込む入力側回路と、取り込
んだ測定入力を所定の形式の電気信号に変換して伝送線
に送出する出力側回路と、測定入力を入力側回路から出
力側回路へ絶縁伝送する絶縁伝送回路と、出力側回路に
ある電源の電力を入力側回路に供給するＤＣ／ＤＣ変換
器と、伝送線から送られてくる信号を監視し、伝送線か
ら送られてくる電気信号に通信データが重畳されている
ことを検出したときは、前記不揮発性メモリにデータの
書き込みを行い、前記不揮発性メモリにデータを書き込
むときは、前記ＤＣ／ＤＣ変換器の動作を停止するとと
もに、停止直前における伝送器の出力を保持する演算制
御部と、を具備したことを特徴とする二線式信号伝送
器。(1) In a two-wire signal transmitter that converts a physical quantity measured by a sensor into an electric signal and transmits the electric signal to the load side through two transmission lines, the electric signal is superimposed on the electric signal on the transmission line. The non-volatile memory in which the measured data is written, the input side circuit that captures the measurement input of the sensor, the output side circuit that converts the captured measurement input into an electric signal of a predetermined format and sends it out to the transmission line, and the measurement input An insulation transmission circuit that performs insulation transmission from the input side circuit to the output side circuit, a DC / DC converter that supplies the power of the power source in the output side circuit to the input side circuit, and monitors the signal sent from the transmission line, Transmission line
Communication data is superimposed on the electric signal sent from
When this is detected, the data in the non-volatile memory
When writing and writing data in the non-volatile memory, the operation control unit that stops the operation of the DC / DC converter and holds the output of the transmitter immediately before the stop is provided. Two-wire signal transmitter.
【００１０】（２）前記ＤＣ／ＤＣ変換器は自励式ＤＣ
／ＤＣ変換器であることを特徴とする（１）記載の二線
式信号伝送器。(2) The DC / DC converter is a self-excited DC
The two-wire signal transmitter according to (1), which is a / DC converter.
【００１１】（３）前記ＤＣ／ＤＣ変換器は他励式ＤＣ
／ＤＣ変換器であることを特徴とする（１）記載の二線
式信号伝送器。(3) The DC / DC converter is a separately excited DC
The two-wire signal transmitter according to (1), which is a / DC converter.
【００１２】[0012]
【発明の実施の形態】以下図面を用いて本発明を詳しく
説明する。図１は本発明の一実施例を示す構成図であ
る。図１で図３と同一のものは同一符号を付ける。この
実施例はＤＣ／ＤＣ変換器が自励式ＤＣ／ＤＣ変換器で
ある場合を示している。DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. 1 that are the same as those in FIG. 3 are given the same reference numerals. In this embodiment, the DC / DC converter is a self-excited DC / DC converter.
【００１３】演算制御部１３０の制御信号はダイオード
ＤＳＷを介してＤＣ／ＤＣ変換器ＣＯＮに与えられてい
る。The control signal of the arithmetic control unit 130 is given to the DC / DC converter CON through the diode DSW.
【００１４】演算制御部１３０は、伝送線から送られて
くる信号を監視し、伝送線から送られてくる電気信号
（実施例では４〜２０ｍＡの電流信号）に通信データが
重畳されていることを検出したときは、不揮発性メモリ
１２５にデータの書き込みを行う。不揮発性メモリ１２
５にデータを書き込むときは、演算制御部１３０からの
制御信号でダイオードＤＳＷをオンにし、トランジスタ
Ｑ３をオフにすることによってＤＣ／ＤＣ変換器ＣＯＮ
の動作を止める。The arithmetic control unit 130 monitors the signal sent from the transmission line, and the communication data is superimposed on the electric signal (current signal of 4 to 20 mA in the embodiment) sent from the transmission line. When is detected, the data is written in the nonvolatile memory 125. Non-volatile memory 12
When data is written in 5, the DC / DC converter CON is turned on by turning on the diode DSW and turning off the transistor Q3 by the control signal from the arithmetic control unit 130.
Stop the operation of.
【００１５】ＤＣ／ＤＣ変換器ＣＯＮの動作が止まる
と、入力側回路１１に電力が供給されない。このため、
新たな測定入力が入力側回路１１から出力側回路１２へ
伝送されなくなる。演算制御部１３０はＤＣ／ＤＣ変換
器ＣＯＮの動作を止めたときは、ＤＣ／ＤＣ変換器を止
める直前の出力を自身のメモリに保持しておく。これに
よって、伝送器の出力はＤＣ／ＤＣ変換器を止める直前
の状態が保持される。When the operation of the DC / DC converter CON is stopped, electric power is not supplied to the input side circuit 11. For this reason,
No new measurement input is transmitted from the input side circuit 11 to the output side circuit 12. When the operation control unit 130 stops the operation of the DC / DC converter CON, it holds the output just before stopping the DC / DC converter in its own memory. As a result, the output of the transmitter is maintained in the state immediately before the DC / DC converter is stopped.
【００１６】不揮発性メモリ１２５（ＥＥＰＲＯＭ）へ
の書き込み頻度は低く、書き込みに要する時間もわずか
であるため、ＤＣ／ＤＣ変換器を止めても実用上の支障
はほとんどない。書き込みが終わったら、ＤＣ／ＤＣ変
換器の動作を再開し、入力側回路の電源電圧が安定する
のを待ってＡ／Ｄ変換を再開する。Since the frequency of writing to the non-volatile memory 125 (EEPROM) is low and the time required for writing is short, even if the DC / DC converter is stopped, there is almost no practical problem. When the writing is completed, the operation of the DC / DC converter is restarted, and the A / D conversion is restarted after the power supply voltage of the input side circuit is stabilized.
【００１７】図２は本発明の他の実施例を示す構成図で
ある。この実施例はＤＣ／ＤＣ変換器が他励式ＤＣ／Ｄ
Ｃ変換器である場合を示している。演算制御部１３０の
制御信号はＤＣ／ＤＣ変換器ＣＯＮに直接与えられてい
る。不揮発性メモリ１２５にデータを書き込むときは、
演算制御部１３０はＤＣ／ＤＣ変換器ＣＯＮに供給して
いたクロックを止め、トランジスタＱ３をオフにするこ
とによってＤＣ／ＤＣ変換器の動作を止める。FIG. 2 is a block diagram showing another embodiment of the present invention. In this embodiment, the DC / DC converter is a separately excited DC / D.
The case of a C converter is shown. The control signal of the arithmetic control unit 130 is directly given to the DC / DC converter CON. When writing data to the non-volatile memory 125,
The arithmetic control unit 130 stops the clock supplied to the DC / DC converter CON and turns off the transistor Q3 to stop the operation of the DC / DC converter.
【００１８】この場合も図１の実施例と同様に、伝送器
の出力はＤＣ／ＤＣ変換器を止める直前の状態を保持す
る。Also in this case, similarly to the embodiment of FIG. 1, the output of the transmitter maintains the state immediately before the DC / DC converter is stopped.
【００１９】[0019]
【発明の効果】本発明によれば次の効果が得られる。According to the present invention, the following effects can be obtained.
【００２０】請求項１乃至請求項３の発明によれば次の
効果が得られる。
出力が小さいときの伝送器の消費電流に余裕ができ、
回路設計の自由度が上がる。
不揮発性メモリに書き込み時の消費電流が大きいもの
を使用できるため、低コストのメモリを選べる。According to the inventions of claims 1 to 3, the following effects can be obtained. There is a margin in the current consumption of the transmitter when the output is small,
The degree of freedom in circuit design is increased. Since a non-volatile memory that consumes a large amount of current when writing can be used, a low-cost memory can be selected.
【図１】本発明の一実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
【図２】本発明の他の実施例を示す構成図である。FIG. 2 is a configuration diagram showing another embodiment of the present invention.
【図３】従来における二線式信号の構成例を示した図で
ある。FIG. 3 is a diagram showing a configuration example of a conventional two-wire signal.
１０ 二線式信号伝送器 １１ 入力側回路 １２ 出力側回路 ３１，３２ 伝送線 １２５ 不揮発性メモリ １３０ 演算制御部 ＰＣ１ フォトカップラ ＣＯＭ ＤＣ／ＤＣ変換器 10 Two-wire signal transmitter 11 Input side circuit 12 Output side circuit 31,32 Transmission line 125 non-volatile memory 130 Operation control unit PC1 photo coupler COM DC / DC converter
Claims (3)
し、この電気信号を２本の伝送線を介して負荷側に伝送
する二線式信号伝送器において、 伝送線上の電気信号に重畳されたデータが書き込まれる
不揮発性メモリと、 センサの測定入力を取り込む入力側回路と、 取り込んだ測定入力を所定の形式の電気信号に変換して
伝送線に送出する出力側回路と、 測定入力を入力側回路から出力側回路へ絶縁伝送する絶
縁伝送回路と、 出力側回路にある電源の電力を入力側回路に供給するＤ
Ｃ／ＤＣ変換器と、伝送線から送られてくる信号を監視し、伝送線から送ら
れてくる電気信号に通信データが重畳されていることを
検出したときは、前記不揮発性メモリにデータの書き込
みを行い、 前記不揮発性メモリにデータを書き込むとき
は、前記ＤＣ／ＤＣ変換器の動作を停止するとともに、
停止直前における伝送器の出力を保持する演算制御部
と、 を具備したことを特徴とする二線式信号伝送器。1. A two-wire type signal transmitter for converting a physical quantity measured by a sensor into an electric signal and transmitting the electric signal to a load side through two transmission lines, which is superposed on the electric signal on the transmission line. The non-volatile memory in which the measured data is written, the input side circuit that captures the measurement input of the sensor, the output side circuit that converts the captured measurement input into an electrical signal of a predetermined format and sends it out to the transmission line, and the measurement input Insulation transmission circuit that performs insulation transmission from the side circuit to the output side circuit, and D that supplies the power of the power supply in the output side circuit to the input side circuit
The signal sent from the C / DC converter and the transmission line is monitored and sent from the transmission line.
Check that the communication data is superimposed on the incoming electrical signal.
If detected, write data to the nonvolatile memory
And write data to the non-volatile memory, the operation of the DC / DC converter is stopped and
A two-wire signal transmitter, comprising: an arithmetic control unit that holds the output of the transmitter immediately before the stop.
Ｃ変換器であることを特徴とする請求項１記載の二線式
信号伝送器。2. The DC / DC converter is a self-excited DC / D converter.
The two-wire signal transmitter according to claim 1, which is a C converter.
Ｃ変換器であることを特徴とする請求項１記載の二線式
信号伝送器。3. The DC / DC converter is a separately excited DC / D.
The two-wire signal transmitter according to claim 1, which is a C converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28085798A JP3517870B2 (en) | 1998-10-02 | 1998-10-02 | Two-wire signal transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28085798A JP3517870B2 (en) | 1998-10-02 | 1998-10-02 | Two-wire signal transmitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000113361A JP2000113361A (en) | 2000-04-21 |
| JP3517870B2 true JP3517870B2 (en) | 2004-04-12 |
Family
ID=17630952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28085798A Expired - Fee Related JP3517870B2 (en) | 1998-10-02 | 1998-10-02 | Two-wire signal transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3517870B2 (en) |
-
1998
- 1998-10-02 JP JP28085798A patent/JP3517870B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000113361A (en) | 2000-04-21 |
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