JPS6220077Y2 - - Google Patents
Info
- Publication number
- JPS6220077Y2 JPS6220077Y2 JP7643579U JP7643579U JPS6220077Y2 JP S6220077 Y2 JPS6220077 Y2 JP S6220077Y2 JP 7643579 U JP7643579 U JP 7643579U JP 7643579 U JP7643579 U JP 7643579U JP S6220077 Y2 JPS6220077 Y2 JP S6220077Y2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- converter
- voltage
- resistor
- output
- 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
Links
- 230000001681 protective effect Effects 0.000 claims description 13
- 230000005540 biological transmission Effects 0.000 claims description 10
- 230000004888 barrier function Effects 0.000 claims description 5
- 231100001261 hazardous Toxicity 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000002360 explosive Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
Landscapes
- Arrangements For Transmission Of Measured Signals (AREA)
- Safety Devices In Control Systems (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Description
【考案の詳細な説明】
本考案は、温度、圧力、流量等のプロセス量を
変換器側で例えばDC4〜20mAの如き電流信号に
変換して受信側へ一対の伝送線で伝送す２線式の
信号変換装置に関する。[Detailed description of the invention] This invention is a two-wire system that converts process quantities such as temperature, pressure, and flow rate into current signals such as 4 to 20 mA DC on the converter side and transmits them to the receiving side via a pair of transmission lines. The present invention relates to a signal conversion device.
この種の２線式信号変換装置において、変換器
を爆発性ガス等の存在する危険場所に設置する場
合には防爆対策が必要となる。防爆対策として通
常は、本安用のバリヤを伝送線の途中に挿入し、
事故時に危険場所に放出されるパワーを安全限界
値以下に制限することが行われている。ところで
バリヤを用いて事故時の最大電圧、電流を例えば
30V，30mAに制限しても、事故時に変換器側で
消費されるパワーは900mWとかなり大きな値と
なる。この場合でも変換器側においては各電気部
品の温度が本安上許容される値を越えないように
しなければならない。このため変換器の各電気部
品にはパワー的に大きなものを用いなければなら
ず、部品の価格が高くなるとともに、変換器の回
路構成に制約を受ける欠点がある。 In this type of two-wire signal converter, explosion-proof measures are required when the converter is installed in a hazardous location where explosive gas or the like exists. As an explosion-proof measure, an intrinsically safe barrier is usually inserted in the middle of the transmission line.
In the event of an accident, the power released into a hazardous area is limited to below a safe limit value. By the way, using a barrier, the maximum voltage and current at the time of an accident can be calculated, for example.
Even if it is limited to 30V and 30mA, the power consumed by the converter in the event of an accident will be quite large at 900mW. Even in this case, it is necessary to ensure that the temperature of each electrical component on the converter side does not exceed an allowable value for intrinsic safety. For this reason, each electrical component of the converter must have a large power, which increases the cost of the components and has the disadvantage that the circuit configuration of the converter is restricted.
本考案では、変換器側で温度対策を必要とする
部分を集中化し、他の部分には一般回路を安全に
使用できるようにして、上述の如き欠点のない新
規な本質安全防爆回路の２線式信号変換装置を実
現したものである。 This invention centralizes the parts that require temperature measures on the converter side, and allows general circuits to be used safely in other parts, creating a new two-wire intrinsically safe explosion-proof circuit that does not have the drawbacks mentioned above. This realizes a signal conversion device based on the following equations.
第１図は本考案の一実施例に示す接続図であ
る。図において、１は危険場所に設置された変換
器、２は安全場所に設置された負荷、３は安全場
所に設置された直流電源で、負荷２と直列に接続
されている。４は変換器１と受信器側の負荷２お
よび電源３とを結ぶ一対の伝送線、５は伝送線の
途中に挿入された本安用のバリヤで、事故時に変
換器１側への電圧、電流を例えば最大30V，
30mAに制限するものである。 FIG. 1 is a connection diagram showing an embodiment of the present invention. In the figure, 1 is a converter installed in a hazardous area, 2 is a load installed in a safe area, and 3 is a DC power supply installed in a safe area, which is connected in series with the load 2. 4 is a pair of transmission lines connecting the converter 1 and the load 2 and power supply 3 on the receiver side; 5 is an intrinsically safe barrier inserted in the middle of the transmission line; For example, the current is up to 30V,
It is limited to 30mA.
変換器１において、１１はプロセス量を検出し
それに応じた信号電圧Ｅiを発生する検出器、１
２はツエナーダイオードで、FETからなる定電
流回路１３より一定電流Isが供給され、その両端
に安定化した電圧Ｅsを生ずるものである。１４
は高利得の差動増幅器で、その入力端子（＋）に
は電圧ＥSを抵抗R1，R2で分圧した電圧E1と信号
電圧Ｅiの和が抵抗R5を介して加えられるととも
に、帰還電圧Ｅfが抵抗R6を介して加えられ、他
方の入力端子（−）には一定電圧Ｅsを抵抗R3，
R4で分圧した電圧E2がさらに抵抗R7，R8で分圧
されて加えられている。なお抵抗R5，R8は信号
源抵抗に比して充分に大きく選ばれている。差動
増幅器１４の出力は抵抗R9を介して制御用トラ
ンジスタ１５のベースに加えられている。そして
検出器１１、ツエナーダイオード１２、定電流回
路１３、差動増幅器１４、制御用トランジスタ１
５および抵抗R1〜R10からなる回路Ａは、温度対
策を施さない一般回路がそのまま用いられてい
る。１６は出力トランジスタで、そのエミツタに
は伝送線４の一方がダイオードＤを介して接続さ
れ、コレクタは二重化されたツエナーダイオード
１７，１８と帰還抵抗Ｒfの直列回路を介して伝
送線４の他方に接続されている。またベースは安
全保持部品の保護抵抗R11を介して制御用トラン
ジスタ１５のコレクタに接続され、差動増幅器１
４の出力に応じた制御用トランジスタ１５のコレ
クタ電流が、出力トランジスタ１６のベース電流
となる。そして出力トランジスタ１６は、出力電
流Ioをツエナーダイオード１７，１８、帰還抵抗
Ｒfおよび伝送線４を介して負荷２に供給する。
出力電流Ioによつて帰還抵抗Ｒfの両端に生ずる
電圧降下が前記帰還電圧Ｅfとなる。したがつて
差動増幅器１４のゲインが充分に大きければ、そ
の入力端子（＋）と（−）にそれぞれ与えられる
電圧の差は実質的に零となり、出力電流Ioは信号
電圧Ｅiに正確に対応したものとなる。二重化さ
れたツエナーダイオード１７，１８の両端電圧が
安全保持部品の保護抵抗R12を介して検出器１１
および差動増幅器１４の電源端子に供給されると
ともに、安全保持部品の保護抵抗R13を介して定
電流回路１３とツエナーダイオード１２の直列回
路に供給されている。そして出力トランジスタ１
６およびツエナーダイオード１７，１８を含む回
路Ｂは、各部品にパワー的に大きなものを用い、
かつ出力トランジスタ１６およびツエナーダイオ
ード１７には放熱板（（図示せず）を取付る等の
処置を施し、事故時に温度が本安上許容される値
以上に上昇しないようにしてある。なお出力トラ
ンジスタ１６のエミツタ、コレクタ間に接続され
た抵抗R14は起動用である。 In the converter 1, a detector 11 detects a process amount and generates a signal voltage E i corresponding to the process amount.
2 is a Zener diode, to which a constant current Is is supplied from a constant current circuit 13 consisting of an FET, and a stabilized voltage Es is generated across the Zener diode. 14
is a high-gain differential amplifier, and the sum of the voltage E 1 obtained by dividing the voltage E S by resistors R 1 and R 2 and the signal voltage E i is applied to its input terminal (+) via the resistor R 5 . At the same time, a feedback voltage E f is applied via a resistor R 6 , and a constant voltage E s is applied to the other input terminal (-) through a resistor R 3 ,
The voltage E 2 divided by R 4 is further divided by resistors R 7 and R 8 and applied. Note that the resistors R 5 and R 8 are selected to be sufficiently large compared to the signal source resistance. The output of the differential amplifier 14 is applied to the base of the control transistor 15 via a resistor R9 . Detector 11, Zener diode 12, constant current circuit 13, differential amplifier 14, control transistor 1
5 and resistors R1 to R10 , a general circuit without any temperature measures is used as is. 16 is an output transistor, the emitter of which is connected to one side of the transmission line 4 via a diode D, and the collector connected to the other side of the transmission line 4 via a series circuit of dual Zener diodes 17 and 18 and a feedback resistor R f . It is connected to the. In addition, the base is connected to the collector of the control transistor 15 via the protective resistor R11 , which is a safety component, and the differential amplifier 1
The collector current of the control transistor 15 corresponding to the output of the transistor 4 becomes the base current of the output transistor 16. The output transistor 16 then supplies the output current Io to the load 2 via the Zener diodes 17 and 18, the feedback resistor Rf , and the transmission line 4.
The voltage drop produced across the feedback resistor R f by the output current Io becomes the feedback voltage E f . Therefore, if the gain of the differential amplifier 14 is sufficiently large, the difference between the voltages applied to its input terminals (+) and (-) will be substantially zero, and the output current Io will be exactly equal to the signal voltage Ei . It will be compatible. The voltage across the dual Zener diodes 17 and 18 is applied to the detector 11 via the protective resistor R12, which is a safety component.
It is supplied to the power supply terminal of the differential amplifier 14, and is also supplied to the series circuit of the constant current circuit 13 and the Zener diode 12 via the protective resistor R13 , which is a safety component. and output transistor 1
Circuit B including 6 and Zener diodes 17 and 18 uses each component with large power,
In addition, measures such as attaching a heat sink (not shown) to the output transistor 16 and the Zener diode 17 are taken to prevent the temperature from rising above a value allowed for intrinsic safety in the event of an accident. The resistor R14 connected between the emitter and collector of 16 is for starting.
このような構成の本考案においては、検出器１
１や差動増幅器１４を含む回路Ａ側と、出力トラ
ンジスタ１６を含む回路Ｂ側とは安全保持部品か
らなる保護抵抗R11，R12，R13を介して接続さ
れ、かつ回路Ａ側には二重化されたツエナーダイ
オード１７，１８により制限された電圧が供給さ
れているので、事故時に回路Ａ側で消費されるパ
ワーＰは、保護抵抗の値をＲ、ツエナーダイオー
ド１７，１８のツエナー電圧をVzとすれば、Ｐ
Vz2／4Rで与えられる。したがつて、保護抵抗
R11，R12，R13の値を例えばそれぞれ500Ωに選
び、ツエナー電圧Vzを9Vに選ぶと、事故時に回
路Ａ側で消費されるパワーの最大値は45mWとな
り大幅に軽減できる。なお保護抵抗R11，R12，
R13を挿入しない場合の最大消費パワーは270mW
である。このように事故時に回路Ａ側で消費され
るパワーを制限できるので、事故時の温度対策は
回路Ｂ側のみ集中的に施せばよく、回路Ａ側には
温度対策は不要となり、一般回路をそのまま安全
に使用できる。 In the present invention having such a configuration, the detector 1
The circuit A side including 1 and the differential amplifier 14 and the circuit B side including the output transistor 16 are connected via protective resistors R 11 , R 12 , R 13 which are safety maintaining components, and the circuit A side includes the Since a limited voltage is supplied by the dual Zener diodes 17 and 18, the power P consumed on the circuit A side in the event of an accident is determined by the value of the protective resistor being R, and the Zener voltage of the Zener diodes 17 and 18 being Vz. Then, P
It is given by Vz 2 /4R. Therefore, the protective resistance
If the values of R 11 , R 12 , and R 13 are selected to be, for example, 500Ω each, and the Zener voltage Vz is selected to be 9V, the maximum power consumed on the circuit A side in the event of an accident will be 45 mW, which can be significantly reduced. Note that the protective resistances R 11 , R 12 ,
Maximum power consumption without R 13 inserted is 270mW
It is. In this way, the power consumed on the circuit A side in the event of an accident can be limited, so temperature countermeasures in the event of an accident only need to be concentrated on the circuit B side, and there is no need for temperature countermeasures on the circuit A side, allowing the general circuit to be used as is. Safe to use.
なお、第２図に示すようにツエナーダイオード
１７，１８の両端電圧を保護抵抗R12を介して定
電流回路１３側および増幅器１４側に与えるよう
にすれば、保護抵抗R13を省略できる。また抵抗
R9を保護抵抗とすれば、保護抵抗R11の値を小さ
くできる。さらに出力トランジスタ１６は第３図
に示すように伝送線４の負側に接続しても同様に
できる。 Note that, as shown in FIG. 2, if the voltage across the Zener diodes 17 and 18 is applied to the constant current circuit 13 side and the amplifier 14 side via the protective resistor R12 , the protective resistor R13 can be omitted. Also resistance
If R 9 is used as a protection resistor, the value of the protection resistor R 11 can be reduced. Furthermore, the output transistor 16 may be connected to the negative side of the transmission line 4 as shown in FIG.
以上説明したように本考案においては、出力ト
ランジスタに直列に接続されたツエナーダイオー
ドを二重化し、その両端電圧を保護抵抗を介して
検出器や増幅器を含む回路に供給するとともに、
出力トランジスタのベースに保護抵抗を介してコ
レクタが接続されている制御用トランジスタを増
幅器出力で駆動するようにして、事故時に大きな
パワーを消費する部分を集中化し、他の部分には
一般回路を安全に使用できるので、変換器の回路
構成に対する制約を大幅に緩和できる本質安全防
爆回路の２線式信号変換装置が得られる。 As explained above, in the present invention, the Zener diode connected in series with the output transistor is duplicated, and the voltage across it is supplied to the circuit including the detector and the amplifier via the protective resistor.
The control transistor, whose collector is connected to the base of the output transistor via a protective resistor, is driven by the amplifier output, centralizing the part that consumes a large amount of power in the event of an accident, and safely leaving the general circuit in other parts. Therefore, it is possible to obtain a two-wire signal converter with an intrinsically safe explosion-proof circuit that can significantly alleviate restrictions on the circuit configuration of the converter.
第１図は本考案の一実施例を示す接続図、第２
図および第３図は本考案の他の実施例を示す接続
図である。
１……変換器、２……負荷、３……直流電源、
４……伝送線、５……本安用のバリヤ、１１……
検出器、１４……増幅器、１５……制御用トラン
ジスタ、１６……出力トランジスタ、１７，１８
……ツエナーダイオード、R10，R11，R12……保
護抵抗。
Fig. 1 is a connection diagram showing one embodiment of the present invention;
3 and 3 are connection diagrams showing other embodiments of the present invention. 1...Converter, 2...Load, 3...DC power supply,
4...Transmission line, 5...Intrinsically safe barrier, 11...
Detector, 14...Amplifier, 15...Control transistor, 16...Output transistor, 17, 18
... Zener diode, R 10 , R 11 , R 12 ... Protection resistor.
Claims (1)
置された受信器側とを結ぶ一対の伝送線の途中に
本安用のバリヤを挿入して本質安全防爆回路を形
成する２線式の信号変換装置において、出力トラ
ンジスタに直列に接続されるツエナーダイオード
を二重化し、この二重化されたツエナーダイオー
ドの両端電圧を保護抵抗を介して検出器および増
幅器を含む回路に供給するとともに、出力トラン
ジスタのベースに保護抵抗を介してコレクタが接
続されている制御用トランジスタを前記増幅器の
出力で駆動するようにしたことを特徴とする２線
式信号変換装置。 A two-wire signal that forms an intrinsically safe explosion-proof circuit by inserting an intrinsically safe barrier in the middle of a pair of transmission lines that connect the converter installed in a hazardous area and the receiver installed in a safe area. In the converter, the Zener diode connected in series with the output transistor is duplicated, and the voltage across the duplicated Zener diode is supplied via a protective resistor to a circuit including a detector and an amplifier, and is also applied to the base of the output transistor. A two-wire signal conversion device, characterized in that a control transistor whose collector is connected via a protective resistor is driven by the output of the amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7643579U JPS6220077Y2 (en) | 1979-06-04 | 1979-06-04 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7643579U JPS6220077Y2 (en) | 1979-06-04 | 1979-06-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55178798U JPS55178798U (en) | 1980-12-22 |
| JPS6220077Y2 true JPS6220077Y2 (en) | 1987-05-22 |
Family
ID=29309938
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7643579U Expired JPS6220077Y2 (en) | 1979-06-04 | 1979-06-04 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6220077Y2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003005319A1 (en) * | 2001-07-04 | 2003-01-16 | Yamatake Corporation | Intrinsically safe explosion-proof sensor circuit |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200905431A (en) * | 2007-06-04 | 2009-02-01 | Idec Corp | Control device |
| EP3048504B1 (en) * | 2015-01-26 | 2019-06-19 | ams AG | Shunt driver circuit and method for providing an output signal |
-
1979
- 1979-06-04 JP JP7643579U patent/JPS6220077Y2/ja not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003005319A1 (en) * | 2001-07-04 | 2003-01-16 | Yamatake Corporation | Intrinsically safe explosion-proof sensor circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55178798U (en) | 1980-12-22 |
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