JP3991542B2

JP3991542B2 - Programmable controller input / output unit

Info

Publication number: JP3991542B2
Application number: JP36570499A
Authority: JP
Inventors: 英毅野田
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd
Priority date: 1999-12-22
Filing date: 1999-12-22
Publication date: 2007-10-17
Anticipated expiration: 2019-12-22
Also published as: JP2001184108A

Description

【０００１】
【発明の属する技術分野】
本発明は、ＣＰＵユニットや電源ユニットで構成されるプログラマブルコントローラに用いられて外部機器との間で電気信号の入出力を行う入出力ユニットに関するものである。
【０００２】
【従来の技術】
図６は従来の入出力ユニットの一構成例を示しており、外部機器に接続されて電気信号を入力又は出力する入出力部（図示例では出力の構成のみを図示しているので、以下「出力部」という）７ａ〜７ｄと、入出力ユニットや電源ユニットともにマザーボードに装着されたＣＰＵユニット（図示せず）からの命令に応じて出力部７ａ〜７ｄを制御する制御部２と、マザーボードを介して電源ユニット（図示せず）からの電源供給を受けて制御部２の動作電源Ｖｃｃを作成する動作電源部３と、制御部２と出力部７ａ〜７ｄとの間を絶縁して両者の間で信号の授受を行う絶縁回路部（フォトカプラ）５とを備えている。出力部７ａ〜７ｄにおいては、フォトカプラ５のフォトトランジスタのコレクタが外部電源Ｖ１に接続され、フォトトランジスタのエミッタが出力用のトランジスタＴｒのベースに直接接続されるとともにバイアス抵抗を介してトランジスタＴｒのエミッタに接続されている。そして、各出力部７ａ〜７ｄの出力用トランジスタＴｒのエミッタ同士が共通接続され、この共通端子と各出力用トランジスタＴｒのコレクタに設けた出力端子６ａ〜６ｄが外部機器に接続される。
【０００３】
ここで、絶縁回路部５に用いるフォトカプラとしては、通常の数１０kHz程度の出力（又は入出力）の場合には特に電源を必要としない無電源型のフォトカプラが用いられるが、数１００kHz以上の高速な出力（又は入出力）には、いわゆる高速型フォトＩＣカプラが用いられる。この高速型フォトＩＣカプラには通常駆動電源（５Ｖ程度）が必要である。
【０００４】
図７は絶縁回路部８に上記高速型フォトＩＣカプラを用いた入出力ユニットの一構成例を示している。ここで、制御部２の動作電源Ｖｃｃを駆動電源として絶縁回路部８に供給すると制御部２側と出力部７ａ〜７ｄ側を絶縁回路部８で絶縁している意味がなくなってしまうので、出力部７ａ〜７ｄ側に別途駆動電源供給用の駆動電源部１９を設ける必要がある。この駆動電源部１９には、絶縁型のＤＣ／ＤＣコンバータを使って制御部２側から駆動電源を供給する方式と、非絶縁型のＤＣ／ＤＣコンバータを使って外部から駆動電源を供給する方式とが考えられる。前者の絶縁型のＤＣ／ＤＣコンバータを使う方式が理想的であるが、コストが高くつくこと、部品点数が多くなって入出力ユニットの小型化が困難になること等の問題があるので、後者の非絶縁型のＤＣ／ＤＣコンバータを使う方式が一般的である。
【０００５】
【発明が解決しようとする課題】
ところが、駆動電源部１９に上記非絶縁型のＤＣ／ＤＣコンバータを使うと、出力部７ａ〜７ｄ側に電源端子を設けて外部機器から電源を供給することになるため、外部機器の電源が入っている場合、プログラマブルコントローラの電源を落とした状態でも駆動電源部１９が動作してしまい、不要な電力が消費されてしまう。また、場合によっては出力部７ａ〜７ｄの構成上入出力ユニット自体が正常動作でない時（電源オフ時又は制御部２の暴走時）に出力部７ａ〜７ｄの出力がオンになっていることも考えられ、非制御状態で出力部７ａ〜７ｄの出力がオンしてしまうと外部機器の誤動作等の不具合が生じる虞がある。而して、このような状況は外部機器が指定されているもの（例えばモータドライバの駆動パルス出力ユニットなど）であればあまり問題にならないが、外部機器が限定されていない場合には無視することはできない。
【０００６】
本発明は上記事情に鑑みて為されたものであり、その目的とするところは、起動時等において外部機器に対して誤った信号が出力されることを防止したプログラマブルコントローラの入出力ユニットを提供することにある。
【０００７】
【課題を解決するための手段】
請求項１の発明は、上記目的を達成するために、ＣＰＵユニットや電源ユニットで構成されるプログラマブルコントローラに用いられて外部機器との間で電気信号の入出力を行う入出力ユニットであって、外部機器に接続されて電気信号を入力又は出力する入出力部と、ＣＰＵユニットからの命令に応じて入出力部を制御する制御部と、電源ユニットからの電源供給を受けて制御部の動作電源を作成する動作電源部と、制御部と入出力部との間を絶縁して両者の間で信号の授受を行う絶縁回路部と、外部からの電源供給を受けて絶縁回路部の出力部側の二次側駆動電源を作成する駆動電源部と、少なくとも動作電源部からの動作電源供給開始時に駆動電源部から絶縁回路部の出力部側への二次側駆動電源の供給を強制的に停止させる駆動電源停止手段とを備え、駆動電源停止手段は、少なくとも動作電源部からの動作電源供給開始時に制御部をリセットするためのリセット信号を出力するリセット回路部と、駆動電源部との間を絶縁してリセット回路部から出力されたリセット信号を駆動電源部に入力するリセット信号伝達部とを有し、リセット信号の入力中は駆動電源部の動作を停止させて成り、駆動電源部は外部から供給される入力電圧を所望の駆動電源電圧に変換する電圧変換回路を具備し、駆動電源停止手段はリセット信号によって電圧変換回路の動作を強制的に停止させて成り、電圧変換回路は、自己の出力電圧を検出するとともに検出電圧としきい値電圧とを比較して検出電圧がしきい値電圧に略一致するように出力電圧を制御する機能を有し、駆動電源停止手段は、リセット信号によって検出電圧を強制的にしきい値電圧よりも高くして成ることを特徴とし、動作電源部からの動作電源供給開始時に駆動電源停止手段によって絶縁回路部への駆動電源の供給を強制的に停止させるので、絶縁回路部は駆動電源が供給されないために動作せず、制御部の動作が不安定となる起動時等において外部機器に対して誤った信号が出力されることを防止することができる。
【００１１】
請求項２の発明は、請求項１の発明において、電圧変換回路の出力端間に電圧検出用の分圧抵抗を接続し、駆動電源停止手段は、駆動電源部における外部電圧の入力端子と電圧変換回路に検出電圧が入力される検出電圧入力端子との間に挿入されてリセット信号の入力時にオフされるとともにリセット信号の非入力時にオンされるスイッチング素子を具備したことを特徴とし、請求項１の発明と同様の作用を奏する。
【００１２】
請求項３の発明は、上記目的を達成するために、ＣＰＵユニットや電源ユニットで構成されるプログラマブルコントローラに用いられて外部機器との間で電気信号の入出力を行う入出力ユニットであって、外部機器に接続されて電気信号を入力又は出力する入出力部と、ＣＰＵユニットからの命令に応じて入出力部を制御する制御部と、電源ユニットからの電源供給を受けて制御部の動作電源を作成する動作電源部と、制御部と入出力部との間を絶縁して両者の間で信号の授受を行う絶縁回路部と、外部からの電源供給を受けて絶縁回路部の出力部側の二次側駆動電源を作成する駆動電源部と、少なくとも動作電源部からの動作電源供給開始時に駆動電源部から絶縁回路部の出力部側への二次側駆動電源の供給を強制的に停止させる駆動電源停止手段とを備え、駆動電源停止手段は、少なくとも動作電源部からの動作電源供給開始時に制御部をリセットするためのリセット信号を出力するリセット回路部と、駆動電源部との間を絶縁してリセット回路部から出力されたリセット信号を駆動電源部に入力するリセット信号伝達部とを有し、リセット信号の入力中は駆動電源部の動作を停止させて成り、駆動電源部は外部から供給される入力電圧を所望の駆動電源電圧に変換する電圧変換回路を具備し、駆動電源停止手段はリセット信号によって電圧変換回路の動作を強制的に停止させて成り、電圧変換回路は、出力電流を検出するとともに検出レベルが所定のしきい値レベルを超えると動作を停止する機能を有し、駆動電源停止手段は、リセット信号によって検出レベルを強制的にしきい値レベルよりも高くして成ることを特徴とし、動作電源部からの動作電源供給開始時に駆動電源停止手段によって絶縁回路部への駆動電源の供給を強制的に停止させるので、絶縁回路部は駆動電源が供給されないために動作せず、制御部の動作が不安定となる起動時等において外部機器に対して誤った信号が出力されることを防止することができる。
【００１３】
請求項４の発明は、請求項３の発明において、駆動電源停止手段は、駆動電源部における外部電圧の入力端子と電圧変換回路が有する出力電流検出用端子との間に挿入されてリセット信号の入力時にオフされるとともにリセット信号の非入力時にオンされるスイッチング素子を具備したことを特徴とし、請求項３の発明と同様の作用を奏する。
【００１５】
【発明の実施の形態】
（実施形態１）
図１に本発明の実施形態１の概略回路ブロック図を示す。基本的には図７に示した従来例と共通の構成を有しており、外部機器に接続されて電気信号を入力又は出力する入出力部（図示例では出力の構成のみを図示しているので、以下「出力部」という）７ａ〜７ｄと、マイコンを主構成要素とし、ＣＰＵユニットからの命令に応じて出力部７ａ〜７ｄを制御する制御部２と、マザーボードを介して電源ユニット（図示せず）からの電源供給を受けて制御部２の動作電源Ｖｃｃを作成する動作電源部３と、高速型フォトＩＣカプラから成り、制御部２と出力部７ａ〜７ｄとの間を絶縁して両者の間で信号の授受を行う絶縁回路部８と、外部からの電源供給を受けて絶縁回路部８の駆動電源を作成する駆動電源部９と、少なくとも動作電源部３からの動作電源供給開始時に制御部２をリセットするためのリセット信号を出力するリセット回路部１０と、駆動電源部９との間を絶縁してリセット回路部１０から出力されたリセット信号を駆動電源部９に入力するリセット信号伝達部５とを備えている。ここで、説明を簡単にするために制御部２、動作電源部３、リセット回路部１０、絶縁回路部８の入力側並びにリセット信号伝達部５の入力側を制御部ブロック１と呼び、出力部７ａ〜７ｄ、駆動電源部９、絶縁回路部８の出力側並びにリセット信号伝達部５の出力側を出力部ブロック４と呼ぶ。
【００１６】
図２に本実施形態における駆動電源部９の具体回路構成例を示し、図４にその基本回路構成を示す。まず、図４に基づいて駆動電源部９の基本構成を説明する。外部機器などから直流電圧Ｖｉｎ（例えば、２４Ｖ）が入力される入力端子４１に、整流用のダイオード４３と平滑用のコンデンサ４８及びコンデンサ４７の並列回路を介してＤＣ／ＤＣコンバータＩＣの電源電圧端子２６が接続されている。このＤＣ／ＤＣコンバータＩＣは例えばシャープ社製のＤＣ／ＤＣコンバータ（型番：ＩＲ３Ｍ０３Ａ）であって、図３に示すような内部回路構成を有している。フリップフロップ回路３６のセット端子Ｓにはアンドゲート３５の出力端が接続され、このアンドゲート３５の入力端にはコンパレータ３４の出力端及び発振器３２の出力端が接続される。また、発振器３２の出力端はフリップフロップ回路３６のリセット端子Ｒにも接続される。フリップフロップ回路３６の出力Ｑはトランジスタ３７のベースに接続され、トランジスタ３７のコレクタが端子２８となり、抵抗Ｒ３を介して入力端子４１に接続される。トランジスタ３７のエミッタはスイッチング用のトランジスタ３９のベースに接続されるとともにバイアス抵抗３８を介してトランジスタ３９のエミッタに接続される。そして、トランジスタ３９のコレクタ及びエミッタが端子２１，２２となり、端子２１に供給される入力電圧をトランジスタ３９でスイッチングして所望のレベルに変換した直流電圧が出力端子２２とグランド端子２４との間に出力される。
【００１７】
コンパレータ３４は、出力端子２２とグランド端子２４との間に挿入された分圧抵抗Ｒ１，Ｒ２で分圧された検出電圧Ｖｓを検出電圧入力端子２５から取り込み、基準電圧発生回路３３から出力されるしきい値電圧Ｖｒ１と比較している。すなわち、検出電圧Ｖｓがしきい値電圧Ｖｒ１よりも低い場合にはコンパレータ３４の出力がＨレベルとなり、アンドゲート３５の出力は発振器３２の出力に応じてＨ、Ｌが切り替わり、トランジスタ３９のスイッチング動作が行われる。それに対して検出電圧Ｖｓがしきい値電圧Ｖｒ１を超えるとコンパレータ３４の出力がＬレベルとなり、アンドゲート３５の出力は発振器３２の出力に関係なく常にＬとなるため、トランジスタ３９のスイッチング動作が停止する。すなわち、検出電圧がしきい値電圧Ｖｒ１よりも低いときにはトランジスタ３９のオンデューティ比を大きくし、高いときにはオンデューティ比を低くすることで出力電圧を調整するＰＷＭ制御が行われるのである。
【００１８】
また、発振器３２にはオペアンプ３１の出力端が接続されている。このオペアンプ３１は出力電流検出用端子２７から入力される検出電圧Ｖｘ（抵抗Ｒ３の両端電圧）と入力端子２６に入力される入力電圧Ｖｉｎとの差が所定のしきい値電圧３０を超えた場合に発振器３２の発振を停止させることで過電流保護機能を実現している。
【００１９】
ＤＣ／ＤＣコンバータＩＣの出力端子２２にはインダクタ４４を介して平滑コンデンサ４９が接続されており、ＤＣ／ＤＣコンバータＩＣのチョッパ動作によって平滑コンデンサ４９の両端に所望の駆動電圧（例えば直流５Ｖ）が得られる。
【００２０】
次に図２に戻って本実施形態の回路構成を説明する。抵抗Ｒ３とコンデンサ４７との接続点に抵抗Ｒ８を介してスイッチング素子５１のコレクタが接続されるとともに抵抗Ｒ９を介してスイッチング素子５１のベースが接続され、スイッチング素子５１のエミッタがＤＣ／ＤＣコンバータＩＣの検出電圧入力端子２５に接続される。また、スイッチング素子５１のベース−エミッタ間にはリセット信号伝達部５の出力側（フォトトランジスタ）が接続される。このリセット信号伝達部５の入力側（フォトダイオード）にはナンドゲート１１を介して制御部ブロック１からのリセット信号が入力される。なお、ナンドゲート１１の入力にはリセット信号とエラー信号（制御部２の暴走時に出力される信号）が入力されている。
【００２１】
次に本実施形態の動作を説明する。まず、プログラマブルコントローラの電源が落ちていて制御部ブロック１が動作していない状態では、リセット回路部１０からもリセット信号は出力されず、リセット信号伝達部５の出力もオフとなる。このとき、駆動電源部９に外部から電源が供給されていると、スイッチング素子５１には抵抗Ｒ５で制限されたベース電流が流れるためにオンとなり、ＤＣ／ＤＣコンバータＩＣの検出電圧入力端子２５には実際の検出電圧（抵抗Ｒ２の両端電圧）並びにしきい値電圧Ｖｒ１よりも十分に高い電圧が入力されるため、ＤＣ／ＤＣコンバータＩＣの出力電圧が低下して駆動電圧Ｖ１が所定レベル（５Ｖ）よりも十分に低くなる。その結果、絶縁回路部８が動作せず、出力部７ａ〜７ｄの出力がＬレベルに保持される。
【００２２】
一方、プログラマブルコントローラの電源が投入されてから制御部２の動作が安定するまではリセット回路部１０からリセット信号が出力されるが、リセット信号が出力されている間はリセット信号伝達部５の出力がオフとなってスイッチング素子５１がオンし、上述と同様に絶縁回路部８が動作せずに出力部７ａ〜７ｄの出力がＬレベルに保持される。そして、制御部２の動作が安定してリセット信号が出力されなくなれば、スイッチング素子５１がオフしてＤＣ／ＤＣコンバータＩＣの検出電圧入力端子２５に分圧抵抗Ｒ２の両端電圧（本来の検出電圧）Ｖｓのみが入力されるため、駆動電源部９から絶縁回路部８に所定の駆動電圧Ｖａが供給されて通常の動作が行われる。
【００２３】
（実施形態２）
図５に本発明の実施形態２における駆動電源部９の具体回路構成を示している。但し、基本的な構成は実施形態１と共通するので、共通する構成には同一の符号を付して説明を省略する。
【００２４】
本実施形態では、抵抗Ｒ３及びコンデンサ４７と並列に抵抗Ｒ４，Ｒ５及びスイッチング素子５２の直列回路６２を接続し、抵抗Ｒ４，Ｒ５の接続点をＤＣ／ＤＣコンバータＩＣの出力電流検出用端子２７に接続し、スイッチング素子５２のベースを抵抗Ｒ６を介してＤＣ／ＤＣコンバータＩＣの入力端子２６に接続するとともに抵抗Ｒ７を介してエミッタを接続し、さらにリセット信号伝達部５の出力側を介してスイッチング素子Ｒ７のベース−エミッタ間に接続してある。
【００２５】
次に本実施形態の動作を説明する。まず、プログラマブルコントローラの電源が落ちていて制御部ブロック１が動作していない状態では、リセット回路部１０からもリセット信号は出力されず、リセット信号伝達部５の出力もオフとなる。このとき、駆動電源部９に外部から電源が供給されていると、スイッチング素子５２には抵抗Ｒ６で制限されたベース電流が流れるためにオンとなり、入力電圧を抵抗Ｒ４，Ｒ５で分圧した電圧がＤＣ／ＤＣコンバータＩＣの出力電流検出用端子２７に入力される。ここで、抵抗Ｒ４での電圧降下がしきい値電圧３０以上となるように抵抗Ｒ４，Ｒ５の抵抗値が設定してあるので、ＤＣ／ＤＣコンバータＩＣの過電流保護機能によって発振器３２が停止し、ＤＣ／ＤＣコンバータＩＣも動作を停止する。その結果、絶縁回路部８が動作せず、出力部７ａ〜７ｄの出力がＬレベルに保持される。
【００２６】
一方、プログラマブルコントローラの電源が投入されてから制御部２の動作が安定するまではリセット回路部１０からリセット信号が出力されるが、リセット信号が出力されている間はリセット信号伝達部５の出力がオフとなってスイッチング素子５２がオンし、上述と同様に絶縁回路部８が動作せずに出力部７ａ〜７ｄの出力がＬレベルに保持される。そして、制御部２の動作が安定してリセット信号が出力されなくなれば、リセット信号伝達部５の出力がオンとなり、スイッチング素子５２のベース−エミッタ間電圧が低下してスイッチング素子５２がターンオフする。スイッチング素子５２がオフすると抵抗Ｒ４，Ｒ５による分圧が成立しなくなり（抵抗Ｒ５が見かけ上無限大となる）、しかも出力電流検出用端子２７にはほとんど電流が流れないために抵抗Ｒ４での電圧降下は無視できる。よって、出力電流検出用端子２７と入力端子２６との電位差は抵抗Ｒ３の電圧降下分のみと考えることができるので、ＤＣ／ＤＣコンバータＩＣが通常の動作を行い、駆動電源部９から絶縁回路部８に所定の駆動電圧Ｖａが供給されて通常の動作が行われる。
【００２７】
実施形態１ではＤＣ／ＤＣコンバータＩＣの検出電圧入力端子２５に接続する分圧抵抗の分圧比を切り換えているため、スイッチング素子５１がオフすると抵抗Ｒ５が検出電圧入力端子２５に接続されることになり、抵抗Ｒ１，Ｒ２，Ｒ５の抵抗値の設定が難しくなって出力電圧を精度良く制御することが困難になるので、本実施形態の方が望ましい。
【００２８】
なお、本実施形態では制御部２にマイコンが使われている場合を例示したが、例えばマイコンの代わりにＳＲＡＭタイプのＦＰＧＡ（フィールド・プログラマブル・ゲート・アレイ）を使用した場合にてＦＰＧＡのデータコンフィグレーション中（ＦＰＧＡ）の回路データをＲＯＭからＦＰＧＡに転送する動作）の出力不安定状態の時にも出力部７ａ〜７ｄから誤った振動が出力されるようなことを防ぐことができる。また、実施形態１では出力部７ａ〜７ｄのみを例示したが入力部を備えた構成においても同様の効果を奏することができ、このような入力部の構成は従来周知の技術を用いて実現可能であるから図示並びに説明は省略する。
【００２９】
【発明の効果】
請求項１の発明は、ＣＰＵユニットや電源ユニットで構成されるプログラマブルコントローラに用いられて外部機器との間で電気信号の入出力を行う入出力ユニットであって、外部機器に接続されて電気信号を入力又は出力する入出力部と、ＣＰＵユニットからの命令に応じて入出力部を制御する制御部と、電源ユニットからの電源供給を受けて制御部の動作電源を作成する動作電源部と、制御部と入出力部との間を絶縁して両者の間で信号の授受を行う絶縁回路部と、外部からの電源供給を受けて絶縁回路部の出力部側の二次側駆動電源を作成する駆動電源部と、少なくとも動作電源部からの動作電源供給開始時に駆動電源部から絶縁回路部の出力部側への二次側駆動電源の供給を強制的に停止させる駆動電源停止手段とを備え、駆動電源停止手段は、少なくとも動作電源部からの動作電源供給開始時に制御部をリセットするためのリセット信号を出力するリセット回路部と、駆動電源部との間を絶縁してリセット回路部から出力されたリセット信号を駆動電源部に入力するリセット信号伝達部とを有し、リセット信号の入力中は駆動電源部の動作を停止させて成り、駆動電源部は外部から供給される入力電圧を所望の駆動電源電圧に変換する電圧変換回路を具備し、駆動電源停止手段はリセット信号によって電圧変換回路の動作を強制的に停止させて成り、電圧変換回路は、自己の出力電圧を検出するとともに検出電圧としきい値電圧とを比較して検出電圧がしきい値電圧に略一致するように出力電圧を制御する機能を有し、駆動電源停止手段は、リセット信号によって検出電圧を強制的にしきい値電圧よりも高くして成ることを特徴とし、動作電源部からの動作電源供給開始時に駆動電源停止手段によって絶縁回路部への駆動電源の供給を強制的に停止させるので、絶縁回路部は駆動電源が供給されないために動作せず、制御部の動作が不安定となる起動時等において外部機器に対して誤った信号が出力されることを防止することができるという効果がある。
【００３３】
請求項２の発明は、請求項１の発明において、電圧変換回路の出力端間に電圧検出用の分圧抵抗を接続し、駆動電源停止手段は、駆動電源部における外部電圧の入力端子と電圧変換回路に検出電圧が入力される検出電圧入力端子との間に挿入されてリセット信号の入力時にオフされるとともにリセット信号の非入力時にオンされるスイッチング素子を具備したことを特徴とし、請求項１の発明と同様の効果を奏する。
【００３４】
請求項３の発明は、ＣＰＵユニットや電源ユニットで構成されるプログラマブルコントローラに用いられて外部機器との間で電気信号の入出力を行う入出力ユニットであって、外部機器に接続されて電気信号を入力又は出力する入出力部と、ＣＰＵユニットからの命令に応じて入出力部を制御する制御部と、電源ユニットからの電源供給を受けて制御部の動作電源を作成する動作電源部と、制御部と入出力部との間を絶縁して両者の間で信号の授受を行う絶縁回路部と、外部からの電源供給を受けて絶縁回路部の出力部側の二次側駆動電源を作成する駆動電源部と、少なくとも動作電源部からの動作電源供給開始時に駆動電源部から絶縁回路部の出力部側への二次側駆動電源の供給を強制的に停止させる駆動電源停止手段とを備え、駆動電源停止手段は、少なくとも動作電源部からの動作電源供給開始時に制御部をリセットするためのリセット信号を出力するリセット回路部と、駆動電源部との間を絶縁してリセット回路部から出力されたリセット信号を駆動電源部に入力するリセット信号伝達部とを有し、リセット信号の入力中は駆動電源部の動作を停止させて成り、駆動電源部は外部から供給される入力電圧を所望の駆動電源電圧に変換する電圧変換回路を具備し、駆動電源停止手段はリセット信号によって電圧変換回路の動作を強制的に停止させて成り、電圧変換回路は、出力電流を検出するとともに検出レベルが所定のしきい値レベルを超えると動作を停止する機能を有し、駆動電源停止手段は、リセット信号によって検出レベルを強制的にしきい値レベルよりも高くして成ることを特徴とし、動作電源部からの動作電源供給開始時に駆動電源停止手段によって絶縁回路部への駆動電源の供給を強制的に停止させるので、絶縁回路部は駆動電源が供給されないために動作せず、制御部の動作が不安定となる起動時等において外部機器に対して誤った信号が出力されることを防止することができるという効果がある。
【００３５】
請求項４の発明は、請求項３の発明において、駆動電源停止手段は、駆動電源部における外部電圧の入力端子と電圧変換回路が有する出力電流検出用端子との間に挿入されてリセット信号の入力時にオフされるとともにリセット信号の非入力時にオンされるスイッチング素子を具備したことを特徴とし、請求項３の発明と同様の効果を奏する。
【図面の簡単な説明】
【図１】実施形態１の概略回路ブロック図である。
【図２】同上における駆動電源部の具体回路図である。
【図３】同上におけるＤＣ／ＤＣコンバータの概略回路図である。
【図４】同上における駆動電源部の基本的な具体回路図である。
【図５】実施形態２における駆動電源部の具体回路図である。
【図６】従来例の概略回路ブロック図である。
【図７】他の従来例の概略回路ブロック図である。
【符号の説明】
１制御部ブロック
２制御部
３動作電源部
４出力部ブロック
７ａ〜７ｄ出力部
８絶縁回路部
９駆動電源部
１０リセット回路部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to input and output units for inputting and outputting electrical signals to and from an external device used in a programmable controller consists of a CPU unit and the power supply unit.
[0002]
[Prior art]
FIG. 6 shows an example of the configuration of a conventional input / output unit. An input / output unit that is connected to an external device and inputs or outputs an electrical signal (in the illustrated example, only the output configuration is illustrated. 7a to 7d), a control unit 2 for controlling the output units 7a to 7d according to a command from a CPU unit (not shown) mounted on the motherboard together with the input / output unit and the power supply unit, and the motherboard. The operation power supply unit 3 that generates power supply Vcc of the control unit 2 by receiving power supply from a power supply unit (not shown) through the insulation between the control unit 2 and the output units 7a to 7d And an insulating circuit unit (photocoupler) 5 for transmitting and receiving signals between them. In the output units 7a to 7d, the collector of the phototransistor of the photocoupler 5 is connected to the external power source V1, the emitter of the phototransistor is directly connected to the base of the output transistor Tr, and the transistor Tr is connected via a bias resistor. Connected to the emitter. The emitters of the output transistors Tr of the output units 7a to 7d are connected in common, and the common terminals and output terminals 6a to 6d provided at the collectors of the output transistors Tr are connected to an external device.
[0003]
Here, as the photocoupler used for the insulating circuit unit 5, a non-power source type photocoupler that does not require a power supply is used in the case of a normal output (or input / output) of about several tens of kHz. A so-called high-speed photo IC coupler is used for high-speed output (or input / output). This high-speed photo IC coupler requires a normal drive power supply (about 5V).
[0004]
FIG. 7 shows a configuration example of an input / output unit using the high-speed photo IC coupler in the insulating circuit section 8. Here, if the operation power supply Vcc of the control unit 2 is supplied to the insulation circuit unit 8 as a drive power supply, the meaning that the control unit 2 side and the output units 7a to 7d are insulated by the insulation circuit unit 8 is lost. It is necessary to separately provide a drive power supply unit 19 for supplying drive power to the units 7a to 7d. The drive power supply unit 19 includes a method of supplying drive power from the control unit 2 side using an insulated DC / DC converter, and a method of supplying drive power from the outside using a non-insulated DC / DC converter. You could think so. The former method using an insulated DC / DC converter is ideal, but there are problems such as high cost and difficulty in downsizing the input / output unit due to the increased number of parts. A method using a non-insulated DC / DC converter is generally used.
[0005]
[Problems to be solved by the invention]
However, if the non-insulated DC / DC converter is used for the drive power supply unit 19, the power supply terminal is provided on the output units 7a to 7d side to supply power from the external device. In this case, the drive power supply unit 19 operates even when the power of the programmable controller is turned off, and unnecessary power is consumed. In some cases, the outputs of the output units 7a to 7d may be turned on when the input / output unit itself is not operating normally due to the configuration of the output units 7a to 7d (when the power is off or the control unit 2 is out of control). If the output of the output units 7a to 7d is turned on in a non-controlled state, there is a possibility that a malfunction such as a malfunction of an external device may occur. Thus, this situation is not a problem if an external device is specified (for example, a drive pulse output unit of a motor driver), but should be ignored if the external device is not limited. I can't.
[0006]
The present invention has been made in view of the above circumstances, it is an object of the programmable controller output unit of which prevents an erroneous signal to an external device is output at the start-up or the like It is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is an input / output unit that is used in a programmable controller including a CPU unit and a power supply unit to input / output an electric signal to / from an external device, An input / output unit connected to an external device for inputting or outputting an electrical signal, a control unit for controlling the input / output unit in response to a command from the CPU unit, and an operation power supply for the control unit upon receiving power supply from the power supply unit Operation power supply unit, insulation circuit unit that insulates between control unit and input / output unit and exchanges signals between them, and output side of insulation circuit unit that receives external power supply forcibly stopping the driving power source unit to create a secondary drive power, the supply of secondary driving power from the operating power supply at the start drive power of at least from the operation power supply unit to the output side of the isolation circuit of Drive power And a stop means, the drive power source stop means includes a reset circuit for outputting a reset signal to reset the control unit to the operating power supply at the start at least from the operating power supply unit, and insulating the drive power supply unit A reset signal transmission unit that inputs the reset signal output from the reset circuit unit to the drive power supply unit, and is configured to stop the operation of the drive power supply unit while the reset signal is input, and the drive power supply unit is supplied from the outside A voltage conversion circuit for converting the input voltage to a desired drive power supply voltage, and the drive power supply stop means forcibly stops the operation of the voltage conversion circuit by a reset signal, and the voltage conversion circuit has its own output voltage. And the output voltage is controlled so that the detected voltage substantially matches the threshold voltage by comparing the detected voltage with the threshold voltage. Characterized by comprising higher than forcing the threshold voltage of the detected voltage by the set signal, forcing a supply of driving power to the insulating circuit portion by the drive power source stop means at the start operation power supply from the operating power supply unit Therefore, the isolation circuit unit does not operate because the drive power is not supplied, and the controller does not operate properly, preventing the wrong signal from being output to the external device during startup. Can do.
[0011]
According to a second aspect of the present invention, in the first aspect of the present invention, a voltage detection voltage dividing resistor is connected between the output terminals of the voltage conversion circuit, and the drive power supply stop means is connected to the external voltage input terminal and the voltage in the drive power supply section. A switching element that is inserted between a detection voltage input terminal to which a detection voltage is input to the conversion circuit and is turned off when a reset signal is input and is turned on when no reset signal is input. The same effect as that of the first invention is achieved.
[0012]
The invention of claim 3 is an input / output unit that is used in a programmable controller including a CPU unit and a power supply unit to input / output an electric signal to / from an external device in order to achieve the above object. An input / output unit connected to an external device for inputting or outputting an electrical signal, a control unit for controlling the input / output unit in response to a command from the CPU unit, and an operation power supply for the control unit upon receiving power supply from the power supply unit The operation power supply unit that creates power, the insulation circuit unit that insulates between the control unit and the input / output unit and exchanges signals between them, and the output unit side of the insulation circuit unit that receives external power supply Drive power supply section that creates the secondary drive power supply of the power supply and forcibly stops the supply of secondary drive power from the drive power supply section to the output section side of the insulation circuit section at least when the operation power supply starts from the operation power supply section Drive power The drive power supply stop means insulates between the drive power supply section and a reset circuit section that outputs a reset signal for resetting the control section at least when the operation power supply starts from the operation power supply section. A reset signal transmission unit that inputs the reset signal output from the reset circuit unit to the drive power supply unit, and is configured to stop the operation of the drive power supply unit while the reset signal is input, and the drive power supply unit is supplied from the outside A voltage conversion circuit that converts the input voltage to a desired drive power supply voltage, and the drive power supply stop means forcibly stops the operation of the voltage conversion circuit by a reset signal, and the voltage conversion circuit detects the output current. And a function to stop the operation when the detection level exceeds a predetermined threshold level, and the drive power supply stop means forcibly sets the detection level by a reset signal. Characterized by comprising higher than have value level, the forcibly stopping the supply of the drive power to the insulating circuit portion by the drive power source stop means at the start operation power supply from the operating power supply unit, the insulating circuit portion It is possible to prevent an erroneous signal from being output to an external device at the time of startup or the like that does not operate because the drive power is not supplied and the operation of the control unit becomes unstable .
[0013]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the drive power supply stop means is inserted between the input terminal of the external voltage in the drive power supply section and the output current detection terminal of the voltage conversion circuit, so that the reset signal A switching element that is turned off at the time of input and turned on at the time of non-input of the reset signal is provided, and has the same effect as that of the invention of claim 3 .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 shows a schematic circuit block diagram of Embodiment 1 of the present invention. Basically, it has the same configuration as that of the conventional example shown in FIG. 7, and is connected to an external device to input or output an electrical signal (in the example shown, only the output configuration is shown). Therefore, hereinafter referred to as “output unit”) 7a to 7d, a microcomputer as a main component, a control unit 2 for controlling the output units 7a to 7d in accordance with a command from the CPU unit, and a power supply unit (see FIG. (Not shown) comprising an operation power supply unit 3 for generating an operation power supply Vcc for the control unit 2 by receiving power supply from the control unit 2 and a high-speed photo IC coupler, and insulating between the control unit 2 and the output units 7a to 7d. Insulating circuit unit 8 for transmitting and receiving signals between them, a driving power source unit 9 for generating a driving power source for the insulating circuit unit 8 by receiving external power supply, and starting operation power supply from at least the operating power source unit 3 Sometimes to reset the control unit 2 A reset circuit unit 10 that outputs a reset signal and a reset signal transmission unit 5 that insulates the drive power supply unit 9 and inputs the reset signal output from the reset circuit unit 10 to the drive power supply unit 9 are provided. . Here, in order to simplify the description, the input side of the control unit 2, the operation power supply unit 3, the reset circuit unit 10, the insulating circuit unit 8 and the input side of the reset signal transmission unit 5 are referred to as the control unit block 1, and the output unit 7a to 7d, the drive power supply unit 9, the output side of the insulating circuit unit 8, and the output side of the reset signal transmission unit 5 are referred to as an output unit block 4.
[0016]
FIG. 2 shows a specific circuit configuration example of the drive power supply unit 9 in the present embodiment, and FIG. 4 shows a basic circuit configuration thereof. First, the basic configuration of the drive power supply unit 9 will be described with reference to FIG. A power supply voltage terminal of the DC / DC converter IC is connected to an input terminal 41 to which a DC voltage Vin (for example, 24 V) is input from an external device or the like through a parallel circuit of a rectifying diode 43, a smoothing capacitor 48, and a capacitor 47. 26 is connected. This DC / DC converter IC is, for example, a DC / DC converter (model number: IR3M03A) manufactured by Sharp Corporation, and has an internal circuit configuration as shown in FIG. The output terminal of the AND gate 35 is connected to the set terminal S of the flip-flop circuit 36, and the output terminal of the comparator 34 and the output terminal of the oscillator 32 are connected to the input terminal of the AND gate 35. The output terminal of the oscillator 32 is also connected to the reset terminal R of the flip-flop circuit 36. The output Q of the flip-flop circuit 36 is connected to the base of the transistor 37, the collector of the transistor 37 becomes the terminal 28, and is connected to the input terminal 41 via the resistor R3. The emitter of the transistor 37 is connected to the base of the switching transistor 39 and is connected to the emitter of the transistor 39 via the bias resistor 38. The collector and emitter of the transistor 39 become terminals 21 and 22, and the DC voltage obtained by switching the input voltage supplied to the terminal 21 to the desired level by switching with the transistor 39 is between the output terminal 22 and the ground terminal 24. Is output.
[0017]
The comparator 34 takes in the detection voltage Vs divided by the voltage dividing resistors R 1 and R 2 inserted between the output terminal 22 and the ground terminal 24 from the detection voltage input terminal 25 and outputs it from the reference voltage generation circuit 33. This is compared with the threshold voltage Vr1. That is, when the detection voltage Vs is lower than the threshold voltage Vr1, the output of the comparator 34 becomes H level, the output of the AND gate 35 is switched between H and L according to the output of the oscillator 32, and the switching operation of the transistor 39 is performed. Is done. On the other hand, when the detection voltage Vs exceeds the threshold voltage Vr1, the output of the comparator 34 becomes L level, and the output of the AND gate 35 is always L regardless of the output of the oscillator 32. Therefore, the switching operation of the transistor 39 is stopped. To do. That is, PWM control for adjusting the output voltage by increasing the on-duty ratio of the transistor 39 when the detection voltage is lower than the threshold voltage Vr1 and decreasing the on-duty ratio when the detection voltage is high is performed.
[0018]
Further, the output terminal of the operational amplifier 31 is connected to the oscillator 32. The operational amplifier 31 has a case where the difference between the detection voltage Vx (the voltage across the resistor R3) input from the output current detection terminal 27 and the input voltage Vin input to the input terminal 26 exceeds a predetermined threshold voltage 30. The overcurrent protection function is realized by stopping the oscillation of the oscillator 32.
[0019]
A smoothing capacitor 49 is connected to the output terminal 22 of the DC / DC converter IC via an inductor 44, and a desired drive voltage (for example, DC 5V) is applied to both ends of the smoothing capacitor 49 by the chopper operation of the DC / DC converter IC. can get.
[0020]
Next, returning to FIG. 2, the circuit configuration of the present embodiment will be described. The collector of the switching element 51 is connected to the connection point between the resistor R3 and the capacitor 47 via the resistor R8, and the base of the switching element 51 is connected via the resistor R9. The emitter of the switching element 51 is the DC / DC converter IC. The detection voltage input terminal 25 is connected to the first detection voltage input terminal 25. The output side (phototransistor) of the reset signal transmission unit 5 is connected between the base and emitter of the switching element 51. A reset signal from the control unit block 1 is input to the input side (photodiode) of the reset signal transmission unit 5 via the NAND gate 11. Note that a reset signal and an error signal (a signal output when the control unit 2 runs away) are input to the NAND gate 11.
[0021]
Next, the operation of this embodiment will be described. First, in a state where the power of the programmable controller is turned off and the control unit block 1 is not operating, the reset signal is not output from the reset circuit unit 10 and the output of the reset signal transmission unit 5 is also turned off. At this time, if power is supplied to the driving power supply unit 9 from the outside, the switching element 51 is turned on because the base current limited by the resistor R5 flows, and the switching power supply unit 9 is turned on, and is supplied to the detection voltage input terminal 25 of the DC / DC converter IC. Since a voltage sufficiently higher than the actual detection voltage (the voltage across the resistor R2) and the threshold voltage Vr1 is input, the output voltage of the DC / DC converter IC decreases and the drive voltage V1 becomes a predetermined level (5V). ). As a result, the insulating circuit unit 8 does not operate, and the outputs of the output units 7a to 7d are held at the L level.
[0022]
On the other hand, a reset signal is output from the reset circuit unit 10 until the operation of the control unit 2 is stabilized after the programmable controller is turned on, but the output of the reset signal transmission unit 5 is output while the reset signal is output. Is turned off and the switching element 51 is turned on, and the output of the output units 7a to 7d is held at the L level without the insulation circuit unit 8 operating as described above. When the operation of the control unit 2 is stabilized and the reset signal is not output, the switching element 51 is turned off and the voltage across the voltage dividing resistor R2 (the original detection voltage) is applied to the detection voltage input terminal 25 of the DC / DC converter IC. ) Since only Vs is input, a predetermined drive voltage Va is supplied from the drive power supply unit 9 to the insulating circuit unit 8 to perform a normal operation.
[0023]
(Embodiment 2)
FIG. 5 shows a specific circuit configuration of the drive power supply unit 9 according to the second embodiment of the present invention. However, since the basic configuration is the same as that of the first embodiment, the same configuration is denoted by the same reference numeral and description thereof is omitted.
[0024]
In the present embodiment, a series circuit 62 of resistors R4, R5 and a switching element 52 is connected in parallel with the resistor R3 and the capacitor 47, and the connection point of the resistors R4, R5 is connected to the output current detection terminal 27 of the DC / DC converter IC. The base of the switching element 52 is connected to the input terminal 26 of the DC / DC converter IC via the resistor R6, the emitter is connected via the resistor R7, and switching is performed via the output side of the reset signal transmission unit 5. It is connected between the base and emitter of the element R7.
[0025]
Next, the operation of this embodiment will be described. First, in a state where the power of the programmable controller is turned off and the control unit block 1 is not operating, the reset signal is not output from the reset circuit unit 10 and the output of the reset signal transmission unit 5 is also turned off. At this time, if power is supplied to the drive power supply unit 9 from the outside, the switching element 52 is turned on because the base current limited by the resistor R6 flows, and the input voltage is divided by the resistors R4 and R5. Is input to the output current detection terminal 27 of the DC / DC converter IC. Here, since the resistance values of the resistors R4 and R5 are set so that the voltage drop at the resistor R4 is equal to or higher than the threshold voltage 30, the oscillator 32 is stopped by the overcurrent protection function of the DC / DC converter IC. The DC / DC converter IC also stops operating. As a result, the insulating circuit unit 8 does not operate, and the outputs of the output units 7a to 7d are held at the L level.
[0026]
On the other hand, a reset signal is output from the reset circuit unit 10 until the operation of the control unit 2 is stabilized after the programmable controller is turned on, but the output of the reset signal transmission unit 5 is output while the reset signal is output. Is turned off, the switching element 52 is turned on, and the output of the output units 7a to 7d is held at the L level without the insulation circuit unit 8 operating similarly to the above. When the operation of the control unit 2 is stabilized and the reset signal is not output, the output of the reset signal transmission unit 5 is turned on, the base-emitter voltage of the switching element 52 is lowered, and the switching element 52 is turned off. When the switching element 52 is turned off, voltage division by the resistors R4 and R5 is not established (the resistor R5 appears to be infinite), and the current at the output current detection terminal 27 hardly flows. The descent is negligible. Therefore, since the potential difference between the output current detection terminal 27 and the input terminal 26 can be considered only as the voltage drop of the resistor R3, the DC / DC converter IC performs a normal operation, and the drive power supply unit 9 and the insulation circuit unit. 8 is supplied with a predetermined drive voltage Va to perform a normal operation.
[0027]
In the first embodiment, since the voltage dividing ratio of the voltage dividing resistor connected to the detection voltage input terminal 25 of the DC / DC converter IC is switched, the resistor R5 is connected to the detection voltage input terminal 25 when the switching element 51 is turned off. Therefore, it is difficult to set the resistance values of the resistors R1, R2, and R5, and it becomes difficult to control the output voltage with high accuracy.
[0028]
In the present embodiment, the case where a microcomputer is used for the control unit 2 is illustrated. However, for example, when an SRAM type FPGA (Field Programmable Gate Array) is used instead of the microcomputer, the FPGA data configuration is used. It is possible to prevent an erroneous vibration from being output from the output units 7a to 7d even in an output unstable state during operation (operation of transferring circuit data from FPGA to FPGA). Further, although only the output units 7a to 7d are illustrated in the first embodiment, the same effect can be achieved even in the configuration including the input unit, and such a configuration of the input unit can be realized using a conventionally known technique. Therefore, illustration and description are omitted.
[0029]
【The invention's effect】
The invention according to claim 1 is an input / output unit that is used in a programmable controller including a CPU unit and a power supply unit and inputs / outputs an electrical signal to / from an external device. An input / output unit for inputting or outputting, a control unit for controlling the input / output unit according to a command from the CPU unit, an operation power supply unit for generating an operation power supply for the control unit upon receiving power supply from the power supply unit, Insulation between the control unit and the input / output unit and the transmission and reception of signals between them, and the secondary drive power supply on the output side of the insulation circuit unit is created by receiving external power supply And a drive power supply stop means for forcibly stopping the supply of the secondary drive power from the drive power supply section to the output section side of the insulating circuit section at the start of supply of the operation power supply from at least the operation power supply section. Drive power The stopping means is at least a reset circuit unit that outputs a reset signal for resetting the control unit at the start of supply of operating power from the operating power unit and a reset circuit unit that is output from the reset circuit unit while insulating the drive power unit. A reset signal transmission unit that inputs a signal to the drive power supply unit, and stops the operation of the drive power supply unit while the reset signal is being input. The drive power supply unit supplies the input voltage supplied from the outside to a desired drive power supply. A voltage conversion circuit for converting the voltage into voltage is provided, and the drive power supply stop means forcibly stops the operation of the voltage conversion circuit by a reset signal, and the voltage conversion circuit detects its own output voltage and sets it as a detection voltage. The output voltage is controlled so that the detected voltage substantially matches the threshold voltage by comparing with the value voltage. Forcibly characterized by comprising higher than the threshold voltage, since the forcibly stopping the supply of the drive power to the insulating circuit portion by the drive power source stop means at the start operation power supply from the operating power supply unit, The insulation circuit unit does not operate because the drive power is not supplied, and an effect that an erroneous signal can be prevented from being output to an external device at the time of start-up where the operation of the control unit becomes unstable is obtained. is there.
[0033]
According to a second aspect of the present invention, in the first aspect of the present invention, a voltage detection voltage dividing resistor is connected between the output terminals of the voltage conversion circuit, and the drive power supply stop means is connected to the external voltage input terminal and the voltage in the drive power supply section. A switching element that is inserted between a detection voltage input terminal to which a detection voltage is input to the conversion circuit and is turned off when a reset signal is input and is turned on when no reset signal is input. The same effect as that of the first invention can be obtained.
[0034]
The invention according to claim 3 is an input / output unit that is used in a programmable controller including a CPU unit and a power supply unit and inputs / outputs an electric signal to / from an external device, and is connected to the external device to be an electric signal An input / output unit for inputting or outputting, a control unit for controlling the input / output unit according to a command from the CPU unit, an operation power supply unit for generating an operation power supply for the control unit upon receiving power supply from the power supply unit, Insulation between the control unit and the input / output unit and the transmission and reception of signals between them, and the secondary drive power supply on the output side of the insulation circuit unit is created by receiving external power supply And a drive power supply stop means for forcibly stopping the supply of the secondary drive power from the drive power supply section to the output section side of the insulating circuit section at the start of supply of the operation power supply from at least the operation power supply section. Drive power The stop means is at least a reset circuit unit that outputs a reset signal for resetting the control unit at the start of supply of operating power from the operating power unit, and a reset that is output from the reset circuit unit by insulating the drive power unit. A reset signal transmission unit that inputs a signal to the drive power supply unit, and stops the operation of the drive power supply unit while the reset signal is being input. The drive power supply unit supplies the input voltage supplied from the outside to a desired drive power supply. A voltage conversion circuit for converting the voltage into voltage is provided, and the drive power supply stopping means forcibly stops the operation of the voltage conversion circuit by a reset signal. The voltage conversion circuit detects the output current and detects a predetermined level. It has a function to stop the operation when the threshold level is exceeded, and the drive power supply stop means forcibly sets the detection level higher than the threshold level by the reset signal. Characterized by Rukoto so forcibly stop the supply of the drive power to the insulating circuit portion by the drive power source stop means at the start operation power supply from the operating power supply unit, the insulating circuit portion operates to drive power is not supplied Thus, there is an effect that it is possible to prevent an erroneous signal from being output to the external device at the time of start-up when the operation of the control unit becomes unstable .
[0035]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the drive power supply stop means is inserted between the input terminal of the external voltage in the drive power supply section and the output current detection terminal of the voltage conversion circuit, so that the reset signal A switching element that is turned off at the time of input and turned on at the time of non-input of a reset signal is provided, and an effect similar to that of the invention of claim 3 is achieved.
[Brief description of the drawings]
FIG. 1 is a schematic circuit block diagram of a first embodiment.
FIG. 2 is a specific circuit diagram of the drive power supply unit of the above.
FIG. 3 is a schematic circuit diagram of the DC / DC converter in the same as above.
FIG. 4 is a basic specific circuit diagram of the drive power supply unit of the above.
FIG. 5 is a specific circuit diagram of a drive power supply unit according to the second embodiment.
FIG. 6 is a schematic circuit block diagram of a conventional example.
FIG. 7 is a schematic circuit block diagram of another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control part block 2 Control part 3 Operation | movement power supply part 4 Output part block 7a-7d Output part 8 Insulation circuit part 9 Drive power supply part 10 Reset circuit part

Claims

An input / output unit that is used in a programmable controller composed of a CPU unit and a power supply unit and inputs / outputs electrical signals to / from an external device, and is connected to the external device to input / output electrical signals. A control unit that controls the input / output unit according to a command from the CPU unit, an operation power supply unit that generates power for the control unit upon receiving power supply from the power supply unit, a control unit, and an input / output unit An insulating circuit part that insulates between them and transmits and receives signals between them, a drive power supply part that receives a power supply from the outside and creates a secondary drive power source on the output part side of the insulating circuit part, and at least Drive power supply stop means for forcibly stopping the supply of the secondary side drive power from the drive power supply section to the output section side of the insulating circuit section at the start of operation power supply from the operation power supply section, Less The reset circuit unit that outputs a reset signal for resetting the control unit at the start of operation power supply from the operation power supply unit and the drive power supply unit is insulated from the drive circuit and the reset signal output from the reset circuit unit is used as the drive power source. A reset signal transmission unit that inputs to the unit, and stops the operation of the drive power supply unit during the input of the reset signal, and the drive power supply unit converts the input voltage supplied from the outside into a desired drive power supply voltage A voltage conversion circuit is provided, and the drive power supply stopping means forcibly stops the operation of the voltage conversion circuit by a reset signal. The voltage conversion circuit detects its own output voltage and outputs a detection voltage and a threshold voltage. In comparison, the output voltage is controlled so that the detected voltage substantially matches the threshold voltage, and the drive power supply stopping means forcibly thresholds the detected voltage with a reset signal. Programmable controller input and output unit, characterized by comprising higher than the voltage.

A voltage dividing resistor for voltage detection is connected between the output terminals of the voltage conversion circuit, and the drive power supply stopping means includes an input terminal for an external voltage in the drive power supply unit and a detection voltage input terminal for inputting the detection voltage to the voltage conversion circuit. 2. The input / output unit of a programmable controller according to claim 1 , further comprising a switching element that is inserted between the switching elements and is turned off when a reset signal is inputted and turned on when no reset signal is inputted .

An input / output unit that is used in a programmable controller composed of a CPU unit and a power supply unit and inputs / outputs electrical signals to / from an external device, and is connected to the external device to input / output electrical signals. A control unit that controls the input / output unit according to a command from the CPU unit, an operation power supply unit that generates power for the control unit upon receiving power supply from the power supply unit, a control unit, and an input / output unit An insulating circuit part that insulates between them and transmits and receives signals between them, a drive power supply part that receives a power supply from the outside and creates a secondary drive power source on the output part side of the insulating circuit part, and at least Drive power supply stop means for forcibly stopping the supply of the secondary side drive power from the drive power supply section to the output section side of the insulating circuit section at the start of operation power supply from the operation power supply section, Less The reset circuit unit that outputs a reset signal for resetting the control unit at the start of operation power supply from the operation power supply unit and the drive power supply unit is insulated from the drive circuit and the reset signal output from the reset circuit unit is used as the drive power source. A reset signal transmission unit that inputs to the unit, and stops the operation of the drive power supply unit during the input of the reset signal, and the drive power supply unit converts the input voltage supplied from the outside into a desired drive power supply voltage A voltage conversion circuit is provided, and the drive power supply stop means forcibly stops the operation of the voltage conversion circuit by a reset signal. The voltage conversion circuit detects the output current and the detection level reaches a predetermined threshold level. exceeds a has the function of stopping the operation, the drive power supply stopping means, to characterized in that formed by higher than forcibly threshold level detection level by the reset signal Programmer Lama Bull controller of the input and output unit.

The drive power supply stop means is inserted between the external voltage input terminal of the drive power supply section and the output current detection terminal of the voltage conversion circuit, and is turned off when the reset signal is input and turned on when the reset signal is not input. 4. The input / output unit of the programmable controller according to claim 3 , further comprising a switching element .