JP3662755B2 - Sequence control device - Google Patents

Description

とすると、図３（ａ）に示した例では、

となる。
【００２８】
そして、このオフセットアドレスに対応するコイル出力データ（制御信号）をシーケンステーブル４２から求める。この本実施形態に係るシーケンステーブル４２には、前記オフセットアドレスの全てのパターンに対応したコイル出力データが記録されている。すなわち、図３（ｂ）に示すように、左欄にオフセットアドレスが記述され、これらの各オフセットアドレスに対応するコイル出力データが右欄に記述されている。上述した例では、オフセットアドレスは”１Ｂ”であるため、これに対応するコイル出力データは”３”である。
【００２９】
このコイル出力データは、本実施形態では、コイル出力がア、イの２つであることから、２ビットで表現される。具体的には、
コイル出力データ＝ア,イ
で表現される。ここで、

とすると、図３（ａ）に示した例では、

となる。すなわち、図３（ａ）で示した例では、コイル出力ア、イともにＯＮとなった状態となる。
【００３０】
さらに、このシーケンステーブルに関する他の例を説明する。図４は、他の例として２行２列接点−２出力のラダー回路１２０を示すものである。すなわち、同図に示すように、ラダー回路１２０は、接点（スイッチ）９Ａ〜９Ｄと、出力１１Ａ，１１Ｂと、分岐線１０ａ、１０ｂとから構成される。
【００３１】
同図において、接点９Ａ〜９Ｃは、対象機械８の検出部８１からの信号によってＯＮ及びＯＦＦが切り替わるものである。また、同図において、分岐線１０ａはＯＲ接続を形成しているため、接点９Ｃは、接点９Ａと９ｂにＯＲ接続によって接続されており、接点９Ｄは、常時ＯＮの状態にある開接点であるため、接点９Ｂと出力１１Ｂとは常に接続された状態にある。
【００３２】
また、分岐線１０ｂがＯＦＦとなっているため、出力１１Ａは、接点９ＣにＡＮＤ接続の状態となり、出力１１Ｂは、ＯＲ接続によって接点９Ａ及び９Ｂに接続されていることとなる。従って、出力１１Ａは、接点９Ａ又は９ＢのいずれかがＯＮの状態にあり且つ９ＣがＯＮの状態にあるときＯＮとなるが、出力１１Ｂは、接点９Ａ又は９ＢのいずれかがＯＮの状態にあればＯＮとなる。
【００３３】
いま、対象機械８からの出力によって接点９ＡはＯＦＦの状態にあり、接点９ＢはＯＮの状態にあり、接点９ＣはOFFの状態にある。従って、出力１１ＡはＯＦＦの状態となり、出力１１ＢはＯＮの状態となっている。
【００３４】
このような各接点・分岐情報はオフセットアドレス信号としてメモリ４に送出され、シーケンステーブル４２と参照される。図４に示した例では、

となる。
【００３５】
そして、このオフセットアドレスに対応するコイル出力データ（制御信号）をシーケンステーブル４２から求めると、オフセットアドレスは”１６”に対応するコイル出力データは”１”である。従って、図４に示した例では、

となる。すなわち、図４で示した例では、コイル出力アは、ＯＦＦの状態となり、コイル出力イは、ＯＮとなった状態となる。
（シーケンスプログラムの改変）
次に、メモリ４に記憶されているシーケンスプログラムを改変する際の手順について説明する。この改変は、例えば、対象機械８の動作条件が変更されたとき等に行われる。図５は、プログラマブルシーケンスコントローラ１００内に記録されたシーケンスプログラム４１を改変する手順についての説明図である。
【００３６】
同図に示すように、シーケンスプログラム４１の改変は例えばパーソナルコンピュータ等の外部コンピュータ１４を、プログラマブルシーケンスコントローラ１００に備えられているＩＦ７を介して接続する。
【００３７】
この外部コンピュータ１４には、シーケンスプログラム４１を改変するための専用ソフトウェアがインストールされている。この専用ソフトウェアは、メモリ４に記憶されたシーケンスプログラム４１が保持する分岐情報を、外部コンピュータ１４のディスプレイ１４ａにラダー回路図として表示する機能を有する。これにより、ユーザーは分岐情報をラダー回路図として視覚的に把握することができる。そして、この専用ソフトウェアでは、キーボード１４ｂやマウス１４ｃを操作して、ディスプレイ１４ａ上のラダー回路を変更することによって、メモリ４内のプログラム４１を変更することができる。
【００３８】
また、プログラマブルシーケンスコントローラ１００を稼働させた状態でこの専用プログラムを実行した場合には、ディスプレイ１４ａ上に接点のON／OFFをリアルタイムで表示することができ、対象機械８の動作状態をディスプレイ１４ａによって把握することができる。
［第２の実施形態］
（第２実施形態に係るプログラマブルシーケンスコントローラの構成）
次いで、本発明の第２実施形態について説明する。なお、この第２実施形態では、上述した第１実施形態で用いたプログラマブルシーケンスコントローラ１００のメモリ４内に格納されるシーケンスプログラム４１及びシーケンステーブル４２の内容を変更したうえで、第１実施形態で用いたプログラマブルシーケンスコントローラ１００をそのまま用いることができる。
【００３９】
本実施形態では、ラダー回路の規模が大きい場合に、ラダー回路を所定の単位ブロックに分割するとともに、この単位ブロックについてのオフセットアドレスと出力データをシーケンステーブル４２に格納しておき、各単位ブロックについてのラダー演算を順次行って対象機械８に対する制御信号を求めることを特徴とする。
【００４０】
図６は、上述したプログラマブルシーケンスコントローラ１００で対象機械８を制御する場合において、シーケンスラダー回路の最大要素数が多い場合の動作を示す説明図である。なお、同図（ａ）には、最大要素数が多いラダー回路図の一例として６行６列接点・６出力のラダー回路１３０が示されている。
【００４１】
同図（ａ）に示すように、ラダー回路の最大要素数が多い場合には、ラダー回路１３０を複数ブロックに分割し、各ブロック単位でシーケンス演算を行う。具体的には、列毎にブロック２０１〜２０６に分割する。同図（ｂ）は、これらブロックのうちブロック２０１のみを示すものである。
【００４２】
同図（ｂ）に示すように、ブロック２０１は、接点９Ａ〜９Ｆと分岐線１０ａ〜１０ｂと、当該ブロック２０１からの出力１５Ａ〜１５Ｆとから構成されている。詳しくは、ブロック２０１では、接点９Ａと出力１５Ａ、及び接点９Ｂと出力１５ＢはＡＮＤ接続となっている。また、接点９Ｃ及び９Ｄは、分岐線１０ｃがＯＮになっていることによって出力１５Ｃ及び１５Ｄに対してＯＲ接続となっている。さらに、接点９Ｅ及び９Ｆは、分岐線１０ｄがＯＮになっていることによって１５Ｅ及び１５Ｆに対してＯＲ接続となっている。いま、接点９Ａ，９Ｃ，９ＦがＯＮの状態となっており、接点９Ｂ，９Ｄ，９ＥがＯＦＦの状態となっている。
【００４３】
従って、ブロック２０１におけるオフセットアドレスデータは、

となる。
【００４４】
このオフセットアドレスに対応するブロック出力は、図６（ｃ）に示すような、シーケンステーブル４２に格納されている。このシーケンステーブル４２によれば、オフセットアドレス”525”に対応する出力データは、”2F”となる。
【００４５】
これについて詳述すると、図６（ａ）に示すように、ブロック出力１５Ａ〜１５Ｆについては、１５ＢがＯＦＦの状態となっており、それ以外のブロック出力は全てＯＮとなっている。すなわち、

である。
【００４６】
このようにシーケンステーブル４２には、オフセットアドレスと次ブロックへの出力データとの全ての組み合わせが格納されており、このシーケンステーブル４２を参照することにより、演算を行うことなく各ブロックから次のブロックへの出力を求めることができる。
【００４７】
このようにして求められたブロック２０１からの出力結果を用いて、次ブロックであるブロック２０２の出力を求める。すなわち、ブロック２０１からの出力”2F”と接点情報とについてＡＮＤ演算を行う。このＡＮＤ演算によって得られた結果とブロック２０２についての分岐情報とからオフセットアドレスを求める。
【００４８】
ブロック２０１からの出力は、上述したように、”1,0,1,1,1,1（２進）”である。また、ブロック２０２において、接点９Ｇ及び９ＨはＯＦＦであり、接点９Ｃと９Ｅは、開接点となっており、それ以外は全て閉接点となっていることから、ブロック２０２における接点情報は、”0,0,1,0,1,0（２進）”である。従って、これらのＡＮＤ演算の結果は、”0,0,1,0,1,0”となる。また、ブロック２０２における分岐情報は、上４行が全てＯＲ接続となっている。よって、ブロック２０２におけるオフセットアドレスは、

となる。このオフセットアドレス”15E”に対応する次列への出力データは、シーケンステーブル４２より、”3E”となる。同様にして、ブロック２０３〜２０６についての出力を求めると、図５（ａ）に示したように、各ブロックの出力は、各々”20”、”3F”、”3E”、”1C”となる。これらのうち最後に求まるブロック２０６からの出力が、当該ラダー回路のコイル出力データとなる。この例では、ブロック２０６からの出力は”1C”であることから、

となる。
【００４９】
この第２の実施形態に係るプログラマブルシーケンスコントローラによれば、ラダー回路の演算によって求めるべきコイル出力データをシーケンステーブルに予め格納しておくため、演算を要することなくコイル出力を求めることができる。
【００５０】
殊に、本実施形態では、最大要素数が多いラダー回路を複数のブロックに分割し、ブロック毎にブロック出力を求めるため、効率よくシーケンステーブルの参照処理を行うことができる。このとき、１つのシーケンステーブルを繰り返し用いることができるため、シーケンステーブルを格納するメモリ容量を減少することができる。
（第２実施形態に係るプログラマブルシーケンスコントローラの動作）
次いで本実施形態に係るプログラマブルシーケンスコントローラの動作について詳述する。図７は、本実施形態に係るプログラマブルシーケンスコントローラの動作を示すフロー図である。
【００５１】
対象機械８のシーケンス制御が開始されると（Ｓ６０１）、ＣＰＵ２は、検出部８１から入力回路１を介して接点情報を取得する（Ｓ６０２）。次いで、ＣＰＵ２は、第１列目のブロック２０１についてのラダー演算を行う。
【００５２】
先ず、ブロック２０１に対する入力値と接点情報とのＡＮＤ演算を行う（Ｓ６０３）。このとき、ブロック２０１は、第１列目なので、入力値は全てＯＮの値となる。その後、メモリ４内に格納されたシーケンスプログラム４１からブロック２０１における分岐情報を取得する（Ｓ６０４）。そして、ＣＰＵ２は、ＡＮＤ演算の結果と分岐情報とからオフセットアドレスを生成し、このオフセットアドレスについてシーケンステーブル４２を参照し（Ｓ６０５）、コイル出力データを取得する（Ｓ６０６）。
【００５３】
このようにして求められたブロック２０１の出力値は、次のブロック２０２の入力値となることから、ブロック出力値を次ブロックの入力値に代入して（Ｓ６０７）、次のブロック２０２のラダー演算を行う（Ｓ６０８）。
【００５４】
上記Ｓ６０３からＳ６０７のステップを繰り返すことによって、全てのブロック２０２〜２０６についてラダー演算処理を行う。そして、最後のブロック２０６からのコイル出力が対象機械８に対する制御信号となることから、このコイル出力データを制御信号として、出力回路３より対象機械８に対して出力し（Ｓ６０９）、制御を終了する（Ｓ６１０）。
（変更例）
なお、この第２実施形態では、ラダー回路を列毎に分割したが、本発明はこれに限定されるものではない。例えば、上段と下段とに分割して、各段毎に演算を行うようにすることもできる。
［シーケンスプログラムを記録したコンピュータ読み取り可能な記録媒体］
以上説明した第１，２の実施形態における対象機械８の制御は、所定のプログラム言語で表現されたソフトウェアとすることができる。なお、このソフトウェアとしては、例えば周知のＯＳ又は専用のＯＳに関連するものであっても、関連しないものでなくてもよい。ＯＳに関連するものでは、本発明のシーケンスプログラムの機能の一部をＯＳが負担するような場合であっても本発明に含まれる。
そして、このソフトウェアは、図８に示すような、フロッピーディスク等の磁気記録媒体８０１や、ＣＤ−Ｒ、ＣＤ−ＲＷ、ＤＶＤ等の光ディスク８０２、ＲＡＭカード８０３、カセットテープ８０４等のコンピュータ読み取り可能な記録媒体に記録することができる。なお、このコンピュータ読み取り可能な記録媒体としては、例えばＬＡＮで構築されたネットワークにおけるサーバーコンピュータのハードディスク等も含まれる。この場合には、サーバーコンピュータのハードディスク等に保存されたシーケンスプログラムを呼び出し、端末コンピュータで実行するような形態も、本発明の実施の形態に含まれる。
【００５５】
そして、このような記録媒体８０１〜８０４によれば、シーケンス制御プログラムの保存、運搬を容易に行うことができる。また、ＰＣ８０５に対象機械８を接続するとともに、この記録媒体を介してシーケンス制御プログラムをパーソナルコンピュータ（ＰＣ）８０５等で実行することによってＰＣ８０５を用いて対象機械８の制御を行うことができる。さらに、ＰＣ８０５上で本発明のシーケンス制御プログラムを実行し、本プログラムに仮想の検出情報を与えることによって、対象機械の動作をシミュレーションすることができる。
【００５６】
【発明の効果】
本発明に係るシーケンス制御装置によれば、プログラマブルシーケンスコントローラにおいて、対象機械からの入力があってから制御信号を出力するまでの応答時間を短縮し、制御処理をより迅速なものとするとともに、コストの低減及び装置の小形化を実現することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係るプログラマブルシーケンスコントローラの全体構成を示すブロック図である。
【図２】本発明の第１の実施形態に係るプログラマブルシーケンスコントローラの動作を示すフローチャート図である。
【図３】本発明の第１の実施形態に係るプログラマブルシーケンスコントローラの動作を示す説明図であり、（ａ）は本実施形態に係るラダー回路図であり、（ｂ）はシーケンステーブルの内容を示す図である。
【図４】本発明の第１の実施形態に係るプログラマブルシーケンスコントローラの他の動作を示す説明図である。
【図５】本発明の第１の実施形態に係るプログラマブルシーケンスコントローラにおいて、シーケンスプログラムを改変する際の構成を示すブロック図である。
【図６】本発明の第２の実施形態に係るプログラマブルシーケンスコントローラの動作を示す説明図であり、（ａ）は本実施形態に係るラダー回路図であり、（ｂ）は（ａ）中に示すブロック２０１のみを拡大して示した図であり、（ｃ）はシーケンステーブルの内容を示す図である。
【図７】本発明の第２の実施形態に係るプログラマブルシーケンスコントローラの動作を示すフローチャート図である。
【図８】本発明の第１，２の実施形態に係るプログラマブルシーケンスコントローラの動作をプログラム化したソフトウェアを記録したコンピュータ読み取り可能な記録媒体を示す説明図である。
【図９】従来プログラマブルシーケンスコントローラの説明図である。
【符号の説明】
１…入力回路、２…ＣＰＵ、３…出力回路、４…メモリ、５…表示部、６…操作部、７…インターフェース、８…対象機械、８１…検出部、８２…駆動部、１００…プログラマブルシーケンスコントローラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sequence control device that controls the operation of a target machine, and more particularly to a sequence control device that performs arithmetic processing as a program that expresses a relay ladder circuit using an algorithm.
[0002]
[Prior art]
Conventionally, as a sequence circuit that is a main part of a sequence control device, a relay ladder circuit configured by OR or AND connection of a relay contact (switch) and a drive coil with a wiring has been used.
[0003]
However, since this relay ladder circuit is a hardware circuit, when it is intended to modify a part of it, work such as rewiring the wiring connection is required, and the work is complicated and sequence control is required. There was a problem that it took a long time to change the specifications of the apparatus.
[0004]
On the other hand, in recent years, a programmable sequence controller has been developed that uses a program that represents the hardware relay ladder circuit instead of the hardware relay ladder circuit. According to this programmable sequence controller, it is possible to realize the work of reconnecting wiring, which has been conventionally performed, by simply rewriting the sequence program held in the sequence control device, and quickly change the specifications of the sequence control device. be able to. FIG. 9 is an explanatory diagram of the configuration and operation of a conventional programmable sequence controller 500.
[0005]
As shown in FIG. 2A, a conventional programmable sequence controller 500 includes a memory 501 in which a sequence program is stored, an input / output unit 502 that performs input / output with respect to a target machine, a CPU 503 that controls the entire system, And an arithmetic unit 504 that performs logical operation processing on the ladder circuit.
[0006]
In the programmable sequence controller 500 having such a configuration, the sequence ladder circuit is regarded as a switch matrix that expands in the row direction and the column direction, and the column information and the row information are sequentially transmitted from the left end side toward the right output unit. Calculate the output state in each row.
[0007]
More specifically, the ladder circuit shown in FIG. 9B is a grid in which switches (contact points) Cij that are turned ON / OFF based on signals from various sensors provided in the target machine are developed in n rows and m columns. In actuality, they are stored in the apparatus as a sequence program expressed by an algorithm. Wirings in the ladder circuit on this program are arranged in parallel in the row direction, and wirings adjacent in the column direction are connected to each other by branch lines Bij. Outputs OUT1 to OUTn for the drive unit of the target machine are arranged on the right end side of each row. In such a ladder circuit, all types of circuits can be expressed by switching ON / OFF of the contact and AND / OR of the branch line.
[0008]
And in the programmable sequence controller 500, according to the input information from the target machine by setting the normally open, closed contact and branch information of the contact from the operating conditions of the target machine, forming a sequence program and executing this Control the operation of the target machine.
[0009]
In addition, this sequence program is subjected to arithmetic processing for each column of the ladder circuit. Specifically, first, input information about Ci1 to Cn1 and Bi1 to Bn1 in the first column is acquired from the target machine via the input / output unit 502, and the CPU 503 reads a sequence program from the memory 501. The calculation unit 504 is caused to perform calculation for the first column. The calculation unit 504 passes the calculation result for the first column to the CPU 503. Next, the CPU 503 acquires the inputs for the second column Ci2 to Cn2 and Bi2 to Bn2 via the input / output unit 502, and sends them to the calculation unit 504 together with the calculation result of the first column. The calculation unit 504 transfers the calculation result for the second column to the CPU 503 based on the calculation result of the first column and the input information of the second column. By repeating such processing, the matrix moves from the left end side to the right end side of the matrix, and outputs OUT1 to n are obtained. The outputs OUT1 to OUTn are output to the drive unit of the target machine via the input / output unit 502.
[0010]
[Problems to be solved by the invention]
However, in the conventional programmable sequence controller, the calculation for the first column is performed and the calculation for the next second column is performed using the calculation result. Therefore, there is a problem that the response to the target machine is delayed.
[0011]
Further, in the conventional programmable sequence controller, the calculation unit 504 is required to obtain the outputs OUT1 to OUTn. Therefore, the cost required for the calculation unit 504 increases the cost of the entire apparatus and attaches the calculation unit 504. There is a problem that it is difficult to reduce the size of the apparatus due to the space required for the above.
[0012]
Therefore, the present invention has been made in view of the above circumstances, and its purpose is to reduce the response time from the input from the target machine to the output of the control signal in the programmable sequence controller, and control processing It is another object of the present invention to provide a sequence control apparatus that can realize a more rapid process, a reduction in cost, and a reduction in the size of the apparatus.
[0013]
In order to solve the above problems, the present invention provides a control signal for controlling the operation of the target machine based on a ladder circuit formed by ORing or ANDing a plurality of contacts that are turned ON / OFF by a detection signal input from the target machine. A sequence control device for outputting Ladder circuit The A sequence program expressed by an algorithm as a grid-like wiring developed in n rows and m columns A branch information storage unit that holds as branch information, a sequence table that stores all combinations of the detection signal and the branch information, and the control signals corresponding to the detection signal, and a detection input from the target machine Signal and branch information Memory And the control signal corresponding to the branch information is output to the target machine with reference to the branch information stored in the sequence table and the sequence table.
[0014]
Further, the present invention is a control method for a target machine that controls the operation of the target machine based on a ladder circuit formed by OR or ANDing a plurality of contacts that are turned ON / OFF by a detection signal output from the target machine. And said Ladder circuit The A sequence program expressed by an algorithm as a grid-like wiring developed in n rows and m columns The branching information is stored in the storage means, and all combinations of the detection signal and the branch information and the control signals corresponding thereto are stored in the storage means as a sequence table, and the detection signal is stored in the storage means. In addition to obtaining from the target machine, the control table is obtained by referring to the sequence table based on the obtained detection signal and the branch information, and is output to the target machine.
[0015]
Furthermore, the present invention provides a computer-readable recording of a sequence program for controlling the operation of the target machine based on a ladder circuit formed by OR or ANDing a plurality of contacts that are turned ON / OFF by a detection signal output from the target machine. A possible recording medium, Ladder circuit The A sequence program expressed by an algorithm as a grid-like wiring developed in n rows and m columns A step of storing in the storage means as branch information, a step of storing in the storage means as a sequence table all combinations of the detection signal and the branch information and the control signals corresponding thereto, and acquisition The sequence table is referred to based on the detected signal and the branch information, and the control signal is obtained, and the obtained control signal is output to the target machine.
[0016]
According to the present invention, since all combinations of the control output signals derived from the contact information and the branch information are obtained in advance and stored as a sequence table, when controlling the target machine By acquiring contact information and branch information and referring to these and the sequence table, a control output signal can be quickly obtained. Therefore, the time required for the arithmetic processing can be omitted, and quick sequence control can be realized. In addition, as a result of omitting the arithmetic processing, it is possible to eliminate the need for arithmetic processing means, thereby reducing the size of the apparatus.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
(Configuration of programmable sequence controller 100)
The first embodiment of the present invention will be described below. FIG. 1 is a block diagram showing a schematic configuration of a programmable sequence controller 100 according to the present embodiment.
[0018]
In the figure, a programmable sequence controller 100 includes an input circuit 1 that acquires contact information from the target machine 8, a CPU 2 that controls the entire programmable sequence controller 100, and an output circuit 3 that outputs a control signal for the target machine 8. A memory 4 for storing the sequence program 41 and the sequence table 42, a display unit 5 and an operation unit 6 for operating the programmable sequence controller 100, and an interface (IF) 7 for connecting to an external device. It is roughly composed of
[0019]
The target machine 8 includes a detection unit 81 and a drive unit 82. The detection unit 81 sends the operation state of the target machine 8 as contact information to the programmable sequence controller 100 using a contact sensor, a non-contact sensor, and various sensors such as current, voltage, and temperature. The contact information output from the detector 81 is sent to the input circuit 1 of the programmable sequence controller 100. The drive unit 82 is a drive unit such as each unit drive motor of the target machine 8, and these are controlled by a control signal output from the output circuit 3.
[0020]
The CPU 2 drives the operation unit 6 according to an operation by the user, and displays the operation state of each unit to the user via the display unit 5. Here, as the operation unit 6, various means for inputting a command to the CPU 2, such as a push button switch or an operation switch, can be employed. Moreover, as the display part 5, there exists what displays by a lamp | ramp, LED, CRT etc., for example, The operation state of each part is displayed by this display part 5. FIG. The display unit 5 can also display the operation state of the target machine 8 by displaying an input signal to the input circuit 1.
[0021]
In particular, the CPU 2 outputs the control signal of the target machine 8 with reference to the sequence table 42 for the contact information transferred from the input circuit 1 and the branch information acquired from the program 41 stored in the memory 4. To do.
(Operation of Programmable Sequence Controller 100)
The operation of the programmable sequence controller 100 configured as described above will be described. FIG. 2 is a flowchart showing the operation of the programmable sequence controller 100 according to the present embodiment.
[0022]
When the sequence control of the target machine 8 is started (S201), the CPU 2 acquires contact information from the detection unit 81 via the input circuit 1 (S202). Next, the CPU 2 acquires branch information from the sequence program 41 stored in the memory 4 (S203). Then, the CPU 2 generates an offset address from the contact information and branch information acquired in this way, refers to the sequence table 42 for the offset address (S204), and acquires coil output data. The coil output data is output from the output circuit 3 to the target machine 8 as a control signal for the target machine 8 (S205).
(Configuration of sequence table 42)
In this embodiment, the sequence table 42 is a data table in which all combinations of ON and OFF of the contact information and the output OUT for the branch information OR and AND are expressed in hexadecimal. FIG. 3 is an explanatory diagram of the sequence table 42.
[0023]
FIG. 2A shows a ladder circuit 110 having 2 rows and 2 columns of contacts and 2 outputs as an example of a ladder circuit in order to explain the sequence table 42. That is, as shown in FIG. 5A, the ladder circuit 110 is composed of contacts (switches) 9A to 9D, outputs 11A and 11B, and branch lines 10a and 10b.
[0024]
In FIG. 2A, the contacts 9A to 9C are switched ON and OFF by a signal from the detection unit 81 of the target machine 8. Further, in FIG. 6A, branch lines 10a and 10b are switched between OR connection and AND connection by turning them ON or OFF. That is, an OR connection is formed in the ON state, and an AND connection is formed in the OFF state. ON / OFF of this branch line is acquired from the sequence program 41 stored in the memory 4. In the example shown in the figure, the branch lines 10a and 10b are both in the ON state and form an OR connection.
[0025]
Contact 9C is connected to contacts 9A and 9b by OR connection, while outputs 11A and 11B are connected to contact 9C by OR connection. In FIG. 9A, the contact 9D is a closed contact that is normally OFF, and therefore there is no wiring (dotted line in the figure) that directly connects the contact 9B and the output 11B.
[0026]
Accordingly, when either the contact 9A or 9B is in the ON state and the contact 9C is in the ON state, both the outputs 11A and 11B are turned on. Further, when either the contact 9A or 9B is OFF, or when either the contact 9A or 9B is ON and the contact 9C is OFF, the outputs 11A and 11B are both OFF. In FIG. 9A, the contact 9A is in an OFF state, the contact 9B is in an ON state, and the contact 9C is in an ON state by an output from the target machine 8. Therefore, both outputs 11A and 11B are in an ON state.
[0027]
Such contact / branch information is sent to the memory 4 as an offset address signal and referred to as a sequence table 42. In this embodiment, the offset address signal has contact information (9A to 9D) described in the upper 4 bits and branch information (10a, 10b) described in the lower 2 bits. In particular,
Offset address = A, B, C, D, a, b
It is expressed by here,

Then, in the example shown in FIG.

It becomes.
[0028]
Then, coil output data (control signal) corresponding to this offset address is obtained from the sequence table 42. In the sequence table 42 according to this embodiment, coil output data corresponding to all patterns of the offset address is recorded. That is, as shown in FIG. 3B, offset addresses are described in the left column, and coil output data corresponding to these offset addresses are described in the right column. In the above example, since the offset address is “1B”, the corresponding coil output data is “3”.
[0029]
In this embodiment, the coil output data is represented by 2 bits because the coil outputs are two, i. In particular,
Coil output data = A, A
It is expressed by here,

Then, in the example shown in FIG.

It becomes. That is, in the example shown in FIG. 3A, both the coil outputs A and B are turned on.
[0030]
Furthermore, another example regarding this sequence table will be described. FIG. 4 shows a ladder circuit 120 with 2 rows and 2 columns of contacts-2 output as another example. That is, as shown in the figure, the ladder circuit 120 includes contacts (switches) 9A to 9D, outputs 11A and 11B, and branch lines 10a and 10b.
[0031]
In the figure, the contacts 9 </ b> A to 9 </ b> C are switched ON and OFF by a signal from the detection unit 81 of the target machine 8. In the same figure, since the branch line 10a forms an OR connection, the contact 9C is connected to the contacts 9A and 9b by an OR connection, and the contact 9D is an open contact that is always in an ON state. Therefore, the contact 9B and the output 11B are always connected.
[0032]
Since the branch line 10b is OFF, the output 11A is in an AND connection state with the contact 9C, and the output 11B is connected to the contacts 9A and 9B by OR connection. Therefore, the output 11A is ON when either the contact 9A or 9B is ON and 9C is ON, but the output 11B is either the contact 9A or 9B is ON. If it is ON.
[0033]
Now, the contact 9A is in the OFF state, the contact 9B is in the ON state, and the contact 9C is in the OFF state by the output from the target machine 8. Therefore, the output 11A is in an OFF state and the output 11B is in an ON state.
[0034]
Such contact / branch information is sent to the memory 4 as an offset address signal and referred to as a sequence table 42. In the example shown in FIG.

It becomes.
[0035]
When the coil output data (control signal) corresponding to the offset address is obtained from the sequence table 42, the coil output data corresponding to the offset address “16” is “1”. Therefore, in the example shown in FIG.

It becomes. That is, in the example shown in FIG. 4, the coil output A is in the OFF state, and the coil output A is in the ON state.
(Sequence program modification)
Next, a procedure for modifying the sequence program stored in the memory 4 will be described. This modification is performed, for example, when the operating condition of the target machine 8 is changed. FIG. 5 is an explanatory diagram of a procedure for modifying the sequence program 41 recorded in the programmable sequence controller 100.
[0036]
As shown in the figure, the sequence program 41 is modified by connecting an external computer 14 such as a personal computer via the IF 7 provided in the programmable sequence controller 100.
[0037]
Dedicated software for modifying the sequence program 41 is installed in the external computer 14. This dedicated software has a function of displaying branch information held by the sequence program 41 stored in the memory 4 on the display 14a of the external computer 14 as a ladder circuit diagram. Thereby, the user can visually grasp the branch information as a ladder circuit diagram. With this dedicated software, the program 41 in the memory 4 can be changed by operating the keyboard 14b and the mouse 14c to change the ladder circuit on the display 14a.
[0038]
In addition, when this dedicated program is executed while the programmable sequence controller 100 is in operation, ON / OFF of the contacts can be displayed on the display 14a in real time, and the operation state of the target machine 8 can be displayed by the display 14a. I can grasp it.
[Second Embodiment]
(Configuration of Programmable Sequence Controller according to Second Embodiment)
Next, a second embodiment of the present invention will be described. In the second embodiment, the contents of the sequence program 41 and the sequence table 42 stored in the memory 4 of the programmable sequence controller 100 used in the first embodiment described above are changed, and then the first embodiment. The used programmable sequence controller 100 can be used as it is.
[0039]
In this embodiment, when the scale of the ladder circuit is large, the ladder circuit is divided into predetermined unit blocks, and offset addresses and output data for the unit blocks are stored in the sequence table 42, and each unit block is stored. The control signal for the target machine 8 is obtained by sequentially performing the following ladder calculation.
[0040]
FIG. 6 is an explanatory diagram showing an operation when the maximum number of elements of the sequence ladder circuit is large when the target machine 8 is controlled by the programmable sequence controller 100 described above. FIG. 6A shows a ladder circuit 130 with 6 rows and 6 columns contacts and 6 outputs as an example of a ladder circuit diagram having a large maximum number of elements.
[0041]
As shown in FIG. 6A, when the maximum number of elements of the ladder circuit is large, the ladder circuit 130 is divided into a plurality of blocks, and a sequence operation is performed for each block. Specifically, it is divided into blocks 201 to 206 for each column. FIG. 2B shows only the block 201 among these blocks.
[0042]
As shown in FIG. 2B, the block 201 is composed of contacts 9A to 9F, branch lines 10a to 10b, and outputs 15A to 15F from the block 201. Specifically, in the block 201, the contact 9A and the output 15A and the contact 9B and the output 15B are AND-connected. Further, the contacts 9C and 9D are OR-connected to the outputs 15C and 15D when the branch line 10c is ON. Further, the contacts 9E and 9F are OR-connected to 15E and 15F when the branch line 10d is ON. Now, the contacts 9A, 9C, 9F are in an ON state, and the contacts 9B, 9D, 9E are in an OFF state.
[0043]
Therefore, the offset address data in the block 201 is

It becomes.
[0044]
The block output corresponding to this offset address is stored in a sequence table 42 as shown in FIG. According to the sequence table 42, the output data corresponding to the offset address “525” is “2F”.
[0045]
More specifically, as shown in FIG. 6A, for the block outputs 15A to 15F, 15B is in an OFF state, and all other block outputs are ON. That is,

It is.
[0046]
As described above, the sequence table 42 stores all combinations of the offset address and the output data to the next block. By referring to the sequence table 42, the next block can be processed from each block without performing an operation. Output can be obtained.
[0047]
Using the output result from the block 201 thus obtained, the output of the block 202, which is the next block, is obtained. That is, an AND operation is performed on the output “2F” from the block 201 and the contact information. An offset address is obtained from the result obtained by the AND operation and the branch information for the block 202.
[0048]
As described above, the output from the block 201 is “1,0,1,1,1,1 (binary)”. Further, in the block 202, the contacts 9G and 9H are OFF, the contacts 9C and 9E are open contacts, and all other contacts are closed contacts. Therefore, the contact information in the block 202 is “0”. , 0,1,0,1,0 (binary) ". Therefore, the result of these AND operations is “0,0,1,0,1,0”. Further, the branch information in the block 202 is OR-connected in the upper four rows. Therefore, the offset address in block 202 is

It becomes. The output data to the next column corresponding to the offset address “15E” is “3E” from the sequence table 42. Similarly, when the outputs of the blocks 203 to 206 are obtained, the outputs of the respective blocks are “20”, “3F”, “3E”, and “1C” as shown in FIG. . Of these, the output from the block 206 obtained last is coil output data of the ladder circuit. In this example, the output from block 206 is “1C”.

It becomes.
[0049]
According to the programmable sequence controller according to the second embodiment, since the coil output data to be obtained by the calculation of the ladder circuit is stored in advance in the sequence table, the coil output can be obtained without requiring the calculation.
[0050]
In particular, in the present embodiment, the ladder circuit having the largest number of elements is divided into a plurality of blocks, and the block output is obtained for each block. Therefore, the sequence table can be referred to efficiently. At this time, since one sequence table can be used repeatedly, the memory capacity for storing the sequence table can be reduced.
(Operation of the programmable sequence controller according to the second embodiment)
Next, the operation of the programmable sequence controller according to the present embodiment will be described in detail. FIG. 7 is a flowchart showing the operation of the programmable sequence controller according to the present embodiment.
[0051]
When the sequence control of the target machine 8 is started (S601), the CPU 2 acquires contact information from the detection unit 81 via the input circuit 1 (S602). Next, the CPU 2 performs a ladder calculation for the block 201 in the first column.
[0052]
First, an AND operation is performed on the input value for the block 201 and the contact information (S603). At this time, since the block 201 is in the first column, all input values are ON values. Thereafter, branch information in the block 201 is acquired from the sequence program 41 stored in the memory 4 (S604). Then, the CPU 2 generates an offset address from the result of the AND operation and the branch information, refers to the sequence table 42 for this offset address (S605), and acquires coil output data (S606).
[0053]
Since the output value of the block 201 thus obtained becomes the input value of the next block 202, the block output value is substituted into the input value of the next block (S607), and the ladder calculation of the next block 202 is performed. (S608).
[0054]
By repeating the steps from S603 to S607, ladder calculation processing is performed for all the blocks 202 to 206. Since the coil output from the last block 206 becomes a control signal for the target machine 8, this coil output data is output as a control signal from the output circuit 3 to the target machine 8 (S609), and the control is terminated. (S610).
(Example of change)
In the second embodiment, the ladder circuit is divided for each column, but the present invention is not limited to this. For example, it can be divided into an upper stage and a lower stage, and the calculation can be performed for each stage.
[Computer-readable recording medium recording a sequence program]
The control of the target machine 8 in the first and second embodiments described above can be software expressed in a predetermined program language. The software may be related to, for example, a well-known OS or a dedicated OS, or may not be related. Regarding the OS, even if the OS bears a part of the functions of the sequence program of the present invention, it is included in the present invention.
The software is readable by a computer such as a magnetic recording medium 801 such as a floppy disk, an optical disk 802 such as a CD-R, CD-RW, or DVD, a RAM card 803, a cassette tape 804, etc. as shown in FIG. It can be recorded on a recording medium. The computer-readable recording medium includes, for example, a hard disk of a server computer in a network constructed by a LAN. In this case, an embodiment in which a sequence program stored in a hard disk or the like of a server computer is called and executed by a terminal computer is also included in the embodiment of the present invention.
[0055]
According to such recording media 801 to 804, the sequence control program can be easily stored and transported. In addition, the target machine 8 can be controlled using the PC 805 by connecting the target machine 8 to the PC 805 and executing a sequence control program on the personal computer (PC) 805 or the like via this recording medium. Further, the operation of the target machine can be simulated by executing the sequence control program of the present invention on the PC 805 and giving virtual detection information to the program.
[0056]
【The invention's effect】
According to the sequence control device of the present invention, in the programmable sequence controller, the response time from the input from the target machine to the output of the control signal is shortened, the control processing is made faster, and the cost is reduced. Reduction and downsizing of the apparatus can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a programmable sequence controller according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the programmable sequence controller according to the first embodiment of the present invention.
FIG. 3 is an explanatory diagram showing an operation of the programmable sequence controller according to the first embodiment of the present invention, (a) is a ladder circuit diagram according to the present embodiment, and (b) shows the contents of the sequence table. FIG.
FIG. 4 is an explanatory diagram showing another operation of the programmable sequence controller according to the first embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration when modifying a sequence program in the programmable sequence controller according to the first embodiment of the present invention.
FIG. 6 is an explanatory diagram showing an operation of a programmable sequence controller according to a second embodiment of the present invention, (a) is a ladder circuit diagram according to the present embodiment, and (b) is a diagram in (a). It is the figure which expanded and showed only the block 201 to show, (c) is a figure which shows the content of the sequence table.
FIG. 7 is a flowchart showing the operation of the programmable sequence controller according to the second embodiment of the present invention.
FIG. 8 is an explanatory diagram showing a computer-readable recording medium recording software in which the operation of the programmable sequence controller according to the first and second embodiments of the present invention is programmed.
FIG. 9 is an explanatory diagram of a conventional programmable sequence controller.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Input circuit, 2 ... CPU, 3 ... Output circuit, 4 ... Memory, 5 ... Display part, 6 ... Operation part, 7 ... Interface, 8 ... Target machine, 81 ... Detection part, 82 ... Drive part, 100 ... Programmable Sequence controller

Claims (7)

A sequence control device that outputs a control signal for controlling the operation of the target machine based on a ladder circuit formed by OR or ANDing a plurality of contacts that are turned ON / OFF by a detection signal input from the target machine,
A branch information storage unit that holds, as branch information, a sequence program in which the ladder circuit is expressed by an algorithm as a grid-like wiring developed in n rows and m columns ;
A sequence table storing all combinations of the detection signal and the branch information and the control signals corresponding to the detection signal and the branch information;
The detection signal input from the target machine, the branch information stored in the branch information storage unit and the sequence table are referred to, and the control signal corresponding to the detection signal and the branch information is output to the target machine. A sequence control device. In the sequence control device according to claim 1,
Dividing the ladder circuit into predetermined unit blocks;
The sequence table stores all combinations of the detection signal and the branch information input to each unit block, and the output from the block corresponding to these,
By referring to the sequence table, the output of a certain unit block is obtained, the output of the next unit block is obtained from this output, the output for all unit blocks is obtained by repeating this, and the output from the last unit block is obtained. Is output to the target machine as the control signal. A sequence control device according to claim 1 or 2,
A sequence control apparatus comprising: an operation unit for changing branch information stored in the branch information storage unit according to an operating condition of the target machine. A control method of a target machine for controlling the operation of the target machine based on a ladder circuit formed by OR or ANDing a plurality of contacts that are turned ON / OFF by a detection signal output from the target machine,
A sequence program expressing the ladder circuit by an algorithm as a grid-like wiring developed in n rows and m columns is stored in a storage means as branch information, and the detection signal and the branch information and the corresponding to the detection signal and the branch information are stored. All combinations with control signals are stored in the storage means as a sequence table,
The detection signal is acquired from the target machine, the control table is obtained by referring to the sequence table based on the acquired detection signal and the branch information, and the control signal is output to the target machine. Control method of the target machine. In the control method of the target machine according to claim 4,
Dividing the ladder circuit into predetermined unit blocks;
The sequence table stores all combinations of the detection signal and the branch information input to each unit block, and the output from the block corresponding to these,
By referring to the sequence table, the output of a certain unit block is obtained, the output of the next unit block is obtained from this output, the output for all unit blocks is obtained by repeating this, and the output from the last unit block is obtained. Is output to the target machine as the control signal. A computer-readable recording medium on which a sequence program for controlling the operation of the target machine is recorded based on a ladder circuit in which a plurality of contacts that are turned ON / OFF by a detection signal output from the target machine are connected by OR or AND. And
Storing a sequence program representing the ladder circuit in an algorithm as a grid-like wiring developed in n rows and m columns in a storage means as branch information;
Storing all combinations of the detection signal and the branch information and the control signals corresponding to them in the storage means as a sequence table;
Referring to the sequence table based on the acquired detection signal and the branch information, and obtaining the control signal;
And a step of outputting the obtained control signal to the target machine. A computer-readable recording medium on which a sequence program is recorded. In a computer-readable recording medium in which the sequence program according to claim 6 is recorded,
The sequence table has a data structure storing all combinations of the detection signal and the branch information input to a predetermined unit block obtained by dividing the ladder circuit, and the output from the block corresponding thereto. None,
The sequence program obtains an output for a certain unit block by referring to the sequence table;
Obtaining the output of the next unit block from the output of this unit block,
A computer-readable recording medium on which a sequence program is recorded, characterized in that outputs for all unit blocks are obtained by repeating these steps.

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