JP5125829B2 - Control device, production system, control method, and communication method - Google Patents

Description

The present invention relates to a production system including a plurality of FA devices and a PLC, a communication method in the production system, a control device in the production system, and a control method of the control device.

In a factory that produces many products, various Factory Automation devices (hereinafter referred to as FA devices) are used. In a normal case, some FA devices constitute a group of production systems controlled by a programmable logic controller (hereinafter referred to as PLC). Each main FA device is roughly composed of two parts, a control device and a controlled device.

Examples of the control device include a PLC, a motion controller (hereinafter referred to as MC), a numeric controller (hereinafter referred to as NC device), a robot controller (hereinafter referred to as RC), and the like. The PLC mainly controls these by communicating control signals with other control devices (MC, NC device, RC, etc.). Each of the other control devices communicates with the PLC to control the operation of each controlled device in cooperation with each other. These control devices are usually stored in a control panel in the factory.

On the other hand, the controlled device is controlled by the control devices (MC, NC device, RC, etc.) as described above to convey and process the workpiece, and further perform assembly, inspection, and the like. Examples of MC controlled devices include a belt conveyor that moves the workpiece while it is on the belt, or moves to a predetermined position after grabbing the workpiece and releases the grasped workpiece. Examples include a servo amplifier and a servo motor that drive a transfer robot. Examples of controlled devices of NC devices include servo amplifiers, servo motors, and spindles that drive Numeric Controller machine tools (hereinafter referred to as NC machine tools) that cut the workpiece by moving the cutter to a predetermined coordinate position. Examples include an amplifier and a spindle motor. Examples of RC controlled devices include industrial robots that transport, process, assemble, and inspect workpieces.

Each controlled device normally starts operating upon receiving a command from the control device. In addition, each controlled device does not immediately perform machining or conveyance after starting an operation in response to a command, but before that, the tool of the NC machine tool is moved to a predetermined coordinate position, etc. Requires preparatory action. Therefore, the waiting time until receiving this command as much as possible and the preparation time from the start of operation to the actual processing of the workpiece should be reduced, and the workpiece should always be processed and transported. Is ideal. Reducing such waiting time and preparation time leads to a reduction in tact time. The takt time is the time required to produce one unit of product. In a factory that produces a large number of products, shortening the takt time is an important issue from the viewpoint of improving productivity.

There are mainly two ways to achieve a reduction in tact time. The first means is to reduce the time required for processing performed by each control device itself or operation performed by each controlled device itself. As an example of the former, there is an NC device that eliminates time loss due to the reading time of the machining program block and shortens the tact time (see Patent Document 1). The second means is to shorten the time required to exchange control signals between the control devices.

The second means described above can eliminate the time loss of the entire production system controlled by the PLC, so that the productivity is higher than the first means for reducing the time loss related to each control device itself and each controlled device itself. It can be said that it is very effective from the viewpoint of improvement.

An example of a conventional production system will be described with reference to FIGS. FIG. 12 is a diagram illustrating a configuration example of a conventional production system. The PLC 101 controls the operation of the group of production systems 106 by communicating control signals with a plurality of control devices connected by the bus 111. On the other hand, each control device of the production system 106 connected to the PLC 101 communicates only with the PLC 101. The bus 111 may take any communication form such as wireless, and any device of the production system 106 connected to the PLC 101 may be used. In FIG. 12, for example, the NC device 102, MC 103, device 107, and network unit 108 are used. Cite.

The NC device 102 controls an NC machine tool 104 that processes a workpiece. The NC machine tool 104 is connected to the NC device 102 by wire or wirelessly, and receives a command signal from the NC device 102, a servo amplifier 112, a spindle amplifier 113, and servos driven by the servo amplifier 112 and the spindle amplifier 113, respectively. The motor 114 and the spindle motor 115 are configured. MC103 controls the conveying apparatus 105 which conveys a to-be-processed object. The transport device 105 is connected to the MC 103 by wire or wirelessly, and includes a servo amplifier 116 that receives a command signal from the MC 103 and a servo motor 117 that is driven by the servo amplifier. The device 107 is a plurality of devices controlled by the PLC 101, and is usually a control device such as an NC device or MC. The network unit 108 communicates with a host network including a server 109 and a personal computer (not shown) through the bus 112.

Reference numeral 110 denotes a production system similar to the production system 106, and these production systems are connected in parallel via a bus 112. As a result, the server 109 operates the production systems in cooperation with each other, and when an abnormality occurs in one production system or when a command is received from a personal computer (not shown), this is all or a specific production system. Can be notified. The PLC 101 can communicate with the server 109 and the like via the network unit 108 and controls the production system 106 based on commands received from the server 109 and information held by the server 109.

When the conventional production system 106 shown in FIG. 12 includes a plurality of NC machine tools such as the NC machine tool 104 and a plurality of transfer devices such as the transfer device 105, operations performed by these controlled devices. The flow of will be described. First, the conveying device 105 conveys the workpiece to a position where the NC machine tool 104 can perform machining (this is called loading). Next, the NC machine tool 104 starts processing the workpiece. When the NC machine tool 104 completes machining, the adjacent transfer device transfers this workpiece to the next NC machine tool (this is called unloading), and the transfer device 105 transfers the next workpiece to the NC machine tool. 104 is carried in for processing. By repeating this operation, each workpiece is processed one by one.

FIG. 13 (i) shows a flow of operations performed by the PLC 101, the NC device 102, and the MC 103 from the completion of the work-piece delivery to the start of machining in the conventional production system 106 shown in FIG. FIG. When the transfer device 105 completes the loading of the workpiece, the MC 103 outputs a loading completion signal to the PLC 101. Next, the PLC 101 analyzes the input carry-in completion signal. At this time, the PLC 101 determines whether the NC device 102 performs processing by making various determinations such as whether there is no abnormality in the control device, the controlled device, the bus 111, or the like constituting the production system 106, or whether there is a command from the server 109 Judge whether or not to start. When the NC device 102 determines that the machining can be started, this loading completion signal is output to the NC device 102. When confirming the input carry-in completion signal, the NC device 102 starts machining after performing an operation such as moving the blade of the NC machine tool to a predetermined coordinate position as a machining preparation.

FIG. 13 (ii) shows a flow of operations performed by the PLC 101, the NC device 102, and the MC 103 from the completion of the processing of the workpiece to the start of unloading in the conventional production system 106 shown in FIG. FIG. Similarly to FIG. 13 (i), when the NC machine tool 104 completes the machining of the workpiece, the NC device 102 outputs a machining completion signal to the PLC 101. Next, the PLC 101 analyzes the input processing completion signal, and outputs the processing completion signal to the MC 103 when the transfer device 105 determines that the unloading can be started. When confirming the input processing completion signal, the MC 103 starts the unloading of the workpiece after performing an operation such as moving the arm of the transfer device to a position where the workpiece is present as unloading preparation.

In this way, in the production system 106, in order for the NC machine tool 104 and the transfer device 105 to start operation, the PLC 101 inputs and analyzes each operation completion signal such as a carry-in completion signal and a machining completion signal, and the NC device 102 Therefore, it is necessary to wait until the operation completion signals are output to the MC 103.

Japanese Patent Laid-Open No. 4-367904 (page 3, FIG. 3)

In the conventional production system, in order for the controlled device to start the operation, the PLC inputs and analyzes the operation completion signal, and until the operation completion signal is output to the control device of the controlled device, I had to wait. There is a problem that the waiting time resulting from communication of control signals via the PLC causes an increase in tact time.

The present invention is intended to solve the above-described problems. In a production system supervised by a PLC, the operation completion signal is directly transferred between a plurality of control devices constituting the production system, thereby achieving a tact. The purpose is to shorten the time.

Further, according to the present invention, when one control apparatus receives an operation completion signal from another control apparatus and starts the operation of the controlled apparatus, when the PLC determines an abnormality, the operation of the controlled apparatus is immediately performed. By stopping, the purpose is to guarantee the same function as the conventional production system managed by PLC.

In order to achieve the above object, a control device according to the present invention is connected to a PLC, and controls an operation of the controlled device based on a signal from the PLC, and an external device connected to the PLC outputs wherein a first signal indicative of the operation completion of the external device, the signal receiving unit first of the PLC received a signal to receive a second signal to force out in response to the first signal And the controlled device starting unit that starts the operation of the controlled device based on the first signal received by the signal receiving unit, and the first signal and the second signal are verified and verified And a signal verification unit that continues or stops the operation of the controlled device based on the result.

In the control device according to the next invention, the second signal is the same as the first signal, and the signal collating unit is configured to turn on / off the first signal and turn on / off the second signal. It is characterized by collating the OFF state.

In the control device according to the next invention, the second signal is a command signal relating to the operation of the controlled device, and the signal collating unit determines the content of the command signal, and based on the determined result, the signal It is characterized by controlling the operation of the control device.

In the control device according to the next invention, in the case where the signal collating unit does not receive the other after a predetermined time has elapsed after receiving one of the first signal and the second signal, the controlled device It is characterized by stopping the operation.

The production system according to the present invention is a production system comprising a plurality of control devices and a PLC that communicates with each of the control devices, and the control device completes the operation of an external device output by the other control device. a first signal indicating a signal receiving portion to which the first of the PLC received a signal to receive a second signal to force out in response to the first signal, received by the signal receiving section The controlled device starting unit that starts the operation of the controlled device based on the first signal, the first signal and the second signal are collated, and the controlled device is based on the collation result And a signal verification unit that continues or stops the operation.

In the production system according to the next invention, the second signal is the same as the first signal, and the signal collating unit determines whether the first signal is ON / OFF and whether the second signal is ON / OFF. It is characterized by collating with the OFF state.

In the production system according to the next invention, the second signal is a command signal related to the operation of the controlled device, and the signal collating unit determines the content of the command signal, and based on the determined result, the signal It is characterized by controlling the operation of the control device.

In the production system according to the next invention, when the signal matching unit does not receive one of the first signal and the second signal even after a predetermined time has elapsed after receiving one of the first signal and the second signal, It is characterized by stopping the operation.

Further, the control method according to the present invention includes:
In a control method for controlling the operation of a controlled device based on a signal from a PLC,
A first signal receiving step for receiving a first signal indicating completion of operation of the external device output by the external device connected to the PLC ;
A second signal receiving step of the PLC which receives the first signal receives the second signal to force out in response to the first signal,
A controlled device starting step for starting the operation of the controlled device based on the first signal received in the signal receiving step ;
A signal verification step of verifying the first signal and the second signal;
A verification result processing step of continuing or stopping the operation of the controlled device based on the result of verification in the signal verification step;
It is characterized by having.

In the control method according to the next invention, the second signal is the same as the first signal, and the signal collating step includes the ON / OFF state of the first signal and the ON / OFF state of the second signal. It is characterized by collating with the OFF state.

In the control method according to the next invention, the second signal is a command signal related to the operation of the controlled device, the signal verification step determines the content of the command signal, and the verification result processing step includes The operation of the controlled device is controlled based on the result determined in the signal collating step.

In the control method according to the next invention, in the case where the signal collating step does not receive the other even if a predetermined time elapses after receiving one of the first signal and the second signal, the controlled device It is characterized by stopping the operation.

The communication method according to the present invention includes:
A first signal receiving step for receiving a first signal indicating completion of operation of the external device output by another control device;
A second signal receiving step of receiving a second signal PLC which receives the first signal is the power output in response to the first signal,
A controlled device starting step for starting the operation of the controlled device based on the first signal received in the first signal receiving step ;
A signal verification step of verifying the first signal and the second signal;
A verification result processing step of continuing or stopping the operation of the controlled device based on the result of verification in the signal verification step;
It is characterized by having.

In the communication method according to the next invention, the second signal is the same as the first signal, and the signal collating step includes the ON / OFF state of the first signal and the ON / OFF state of the second signal. It is characterized by collating with the OFF state.

In the communication method according to the next invention, the second signal is a command signal related to the operation of the controlled device, the signal verification step determines the content of the command signal, and the verification result processing step includes The operation of the controlled device is controlled based on the result determined in the signal collating step.

In the communication method according to the next invention, in the case where the signal collating step does not receive the other even if a predetermined time elapses after receiving one of the first signal and the second signal, the controlled device It is characterized by stopping the operation.

By effectively utilizing the waiting time until the control device receives a signal from the PLC, it is possible to reduce time loss due to the fact that the controlled device cannot operate. Thereby, the tact time in the entire production system can be shortened. In addition, it is possible to guarantee a function for controlling a PLC production system equivalent to or higher than that of the conventional one.

Embodiment 1.
Embodiment 1 according to the present invention will be described with reference to FIGS. Here, the same or equivalent parts as those in the configuration example of the conventional production system shown in FIG. FIG. 1 is a diagram illustrating a configuration of a production system according to the first embodiment.

The PLC 101 supervises the operation of the group of production systems 300. Reference numeral 301 denotes an NC apparatus that controls the NC machine tool 104. The MC 302 is an MC and controls the transport device 105. The control device 303 is a plurality of devices such as an NC device and an MC that are controlled by the PLC 101. Network unit 304 communicates with server 109 via bus 112. The NC device 301, MC 302, device 303, and network unit 304 can communicate with each other as well as the PLC 101 via the bus 111. Hereinafter, in order to simplify the description, communication of control signals among the PLC 101, the NC device 301, and the MC 302 will be described.

FIG. 2 (i) shows operations performed by the PLC 101, the NC device 301, and the MC 302 in the production system 300 according to the present embodiment shown in FIG. It is a figure which shows the flow of. When the transfer device 105 completes the workpiece loading, the MC 302 outputs a loading completion signal to the PLC 101 and the NC device 301. Next, the NC device 301 instructs the NC machine tool 104 to prepare for machining based on the input carry-in completion signal. For example, if the NC machine tool performs turning, the turning tool is used. Move to a predetermined position to start machining. That is, the NC machine tool 104 does not start the machining operation when the machining preparation is completed, and the NC device 301 waits for the carry-in completion signal from the PLC 101 to be input. On the other hand, the PLC 101 analyzes the input carry-in completion signal, and outputs the carry-in completion signal to the NC device 301 when the NC device 301 determines that the machining operation of the NC machine tool 104 can be started.

The NC device 301 confirms the loading completion signal when the loading completion signal is input from the PLC 101 within a predetermined time, which will be described later, after the loading completion signal from the MC 302 is input. To start. On the other hand, although not shown in the figure, the NC machine does not start the machining operation and does not start the machining operation when the carry-in completion signal from the PLC 101 is not inputted within a predetermined time after the carry-in completion signal from the MC 302 is inputted. The operation of 104 is stopped.

FIG. 2 (ii) shows an operation performed by the PLC 101, the NC device 301, and the MC 302 in the production system 300 according to the present embodiment shown in FIG. It is a figure which shows the flow of. When the NC machine tool 104 completes the machining of the workpiece, the NC device 301 outputs a machining completion signal to the PLC 101 and the MC 302. Next, the MC 302 commands a preparatory operation for unloading the workpiece based on the input processing completion signal, and when the preparatory operation is completed, the MC 302 completes the processing from the PLC 101 without starting the unloading operation. Wait for the signal to be input. On the other hand, the PLC 101 analyzes the input machining completion signal, and outputs the machining completion signal to the MC 302 when the conveying device 105 determines that the workpiece can be unloaded.

When the machining completion signal is input from the PLC 101 within a predetermined time after the machining completion signal is input from the NC device 301, the MC 302 confirms the machining completion signal and then starts to unload the workpiece. On the other hand, although not shown, when the machining completion signal is not input by the PLC 101 within a predetermined time after the machining completion signal is input from the NC device 301, the operation of the transfer device 105 is stopped without starting the carry-out. To do.

FIG. 3 is a diagram illustrating an internal configuration of the NC device 301 according to the first embodiment. The NC device 301 includes an I / F unit (interface unit) 212 that communicates control signals with the PLCs 101 and MC 302, and a signal processing unit that processes an operation completion signal received from the PLCs 101 and MC 302 via the I / F unit 212. 213, an analysis unit 214 that analyzes a machining program based on a notification received from the signal processing unit 213, and a storage unit 215 that stores data such as the machining program. A person using the NC device 301 can operate the NC device 301 using the display device 209. The NC device 301 controls the NC machine tool 104.

The I / F unit 212 includes a PLC I / F unit 201 and an MC I / F unit 202 corresponding to the PLC 101 and the MC 302, respectively. MC 302 outputs a loading completion signal to MC I / F unit 202 and PLC 101 when conveying device 105 completes loading of the workpiece. Then, the PLC 101 analyzes the carry-in completion signal input from the MC 302 and outputs it to the PLC I / F unit 201.

The signal processing unit 213 includes a signal reception unit 203, a controlled device activation unit 204, and a signal verification unit 205. Hereinafter, as shown in FIG. 2 (i), operations performed by the signal receiving unit 203, the controlled device starting unit 204, and the signal collating unit 205 from the completion of loading of the workpiece to the start of machining will be described. To do.

The signal receiving unit 203 receives a carry-in completion signal that the PLC 101 or the MC 302 outputs to the PLC I / F unit 201 and the MC I / F unit 202, respectively. The controlled device activation unit 204 generates a signal for starting the operation of the NC machine tool 104 based on each carry-in completion signal received by the signal receiving unit 203.

FIG. 4 is a flowchart illustrating a procedure of processes performed by the signal reception unit 203 and the controlled device activation unit 204. First, the signal receiving unit 203 confirms whether or not a carry-in completion signal from the MC 302 is input, that is, whether or not a carry-in completion signal corresponding to the MC 302 is ON or OFF (S301). If it is OFF, the process proceeds to S302. If it is ON, the process proceeds to S303. The signal receiving unit 203 can hold the state of each carry-in completion signal (ON or OFF). In (S302), the signal receiving unit 203 confirms the state of the carry-in completion signal corresponding to the PLC 101. If it is OFF, the process is terminated. If it is ON, the process proceeds to S303.

In (S303), if the controlled device activation unit 204 can confirm that the carry-in completion signal corresponding to the MC 302 or the PLC 101 is ON, the PLC 101 via the PLC I / F unit 201 and the MC I / F unit 202. Then, a program execution notification signal is output (turned ON) to the MC 302, and the process proceeds to S304. This program execution notification signal notifies the PLC 101 and MC 302 whether the machining program is being executed (ON) or stopped (OFF). Each control device can appropriately execute necessary processing based on the turned-on program execution notification signal. Note that S303 is optional, and if omitted, the process proceeds directly to S304.

In (S304), the controlled device activation unit 204 notifies the machining program analysis unit 206 of the analysis unit 214 that the carry-in completion signal corresponding to the MC 302 or the PLC 101 has been turned ON. This notification may be performed by a program execution notification signal that is turned on to the PLC 101 and the MC 302. Then, based on this notification, the machining program analysis processing unit 206 selects a machining program to be executed next by the NC machine tool 104, and acquires the selected machining program from the machining program storage unit 207 of the storage unit 215. The controlled device activation unit 204 instructs the execution of the program acquired by the machining program analysis unit 206 and ends the process.

When the execution of the program is started, the NC machine tool 104 starts machining preparation according to this program. When the process proceeds from S301 to S303, if the loading completion signal corresponding to the PLC 101 is OFF at the time when the machining preparation is completed, the process waits until it is turned ON.

Usually, the carry-in completion signal corresponding to the MC 302 is turned ON before the carry-in completion signal corresponding to the PLC 101. This is because the MC 302 can turn on the carry-in completion signal immediately after the carry-in is completed, but the PLC 101 needs time to analyze the carry-in completion signal before turning on the carry-in completion signal. However, in rare cases, when any abnormality occurs in the MC 302 itself or the bus 111 between the MC 302 and the NC 301, the loading completion signal of the PLC 101 may be turned ON before the loading completion signal of the MC 302. The signal receiving unit 203 and the controlled device activation unit 204 always repeat S301 to S304.

The signal collating unit 205 collates the respective carry-in completion signals corresponding to the PLC 101 and the MC 302, and continues / stops the execution of the machining program started by the signal receiving unit 203 based on the collation result.

FIG. 5 is a flowchart showing a procedure of processing performed by the signal matching unit 205. First, the signal verification unit 205 confirms the state (ON or OFF) of the carry-in completion signal corresponding to the MC 302 (S401). If it is ON, the process proceeds to S402. At this time, the NC machine tool 104 has started preparation for processing through S304. If it is OFF, the process proceeds to S409. Here, when the signal receiving unit 203 holds the states of the respective carry-in completion signals corresponding to the MC 302 and the PLC 101, the signal matching unit 205 can confirm the state of each carry-in completion signal from the signal receiving unit 203. it can. Alternatively, similar to the signal receiving unit 203, these carry-in completion signals may be directly received via the PLC I / F unit 201 and the MC I / F unit 202.

In (S402), the time measuring device 210 provided in the signal verification unit 205 is activated, and the process proceeds to S403. This time measuring device 210 measures the time from the time of activation. In (S403), the collation allowable time parameter is read from the parameter storage unit 208 classified in the storage unit 215, and the process proceeds to S404. The collation allowable time parameter is set in advance by the user of the NC device 301 using the display device 209.

In (S404), the time value measured by the time measuring device 210 is compared with the time value represented by the time parameter read from the parameter storage unit 208. When the time value measured by the time measuring device 210 is equal to or less than the time value represented by the collation allowable time parameter, the process proceeds to S405. When the time value measured by the time measuring device 210 is larger than the time value represented by the collation allowable time parameter, the process proceeds to S407.

Here, when any abnormality occurs in the production system 300, or when any command is given from the server 109, the PLC 101 does not cause the NC machine tool 104 to execute the next machining program. The completion signal is not notified to the NC device 301. By taking this into consideration, the time when the user of the NC device 301 can wait until the NC machine tool 104 is notified of the carry-in completion signal from the PLC 101 without starting the machining is set as a verification allowable time parameter. It is desirable to set.

In (S405), the state of the carry-in completion signal corresponding to the PLC 101 is confirmed. If it is ON, the process proceeds to S406. If it is OFF, the process returns to S404. In (S406), execution of the machining program is continued and the process is terminated. As a result, the NC machine tool 104 starts machining after completing the machining preparation when the machining preparation is not completed, and immediately starts machining when waiting for the completion of the machining preparation. Here, the case where the machine is on standby after the preparation for machining is completed means that the process proceeds from S301 to S303 in FIG. 4 and the loading completion signal corresponding to the PLC 101 is OFF when the machining preparation is completed through S304. It is.

In (S407), since the carry-in completion signal corresponding to the PLC 101 remains OFF even after a predetermined time set as the verification allowable time parameter has elapsed after the carry-in completion signal corresponding to the MC 302 is turned on, the machining program Is stopped, and the process proceeds to S408. As a result, the NC machine tool 104 stops without starting machining. In (S408), the program execution notification signal turned on by the signal receiving unit 203 is turned off, and the process ends. As a result, the PLC 101 and the MC 302 are notified that the execution of the machining program is being stopped.

In (S409), the state (ON or OFF) of the carry-in completion signal corresponding to the PLC 101 is confirmed. If it is ON, the process proceeds to S406. At this time, the NC machine tool 104 has started preparation for processing through S304. If it is OFF, the loading completion signal corresponding to the MC 302 and the PLC 101 is OFF, so the processing is terminated. Here, if it is ON in S409, instead of proceeding to S406, the program execution may be stopped when the carry-in completion signal corresponding to the MC 302 does not turn on after a predetermined time, as in S402 to S408. Good. The signal matching unit 205 always repeats S401 to S409.

In the above, as shown in FIG. 2 (i), the operation performed by the NC apparatus 301 from the completion of loading of the workpiece to the start of machining has been described. On the other hand, as shown in FIG. 2 (ii), the MC 302 has the same internal configuration as that of the NC device 301 and performs the same operation until the unloading is started after the processing of the workpiece is completed. The operation completion signal at this time is a machining completion signal.

Further, in the present embodiment, a method has been described in which the MC 302 and the NC device 301 start the operations of the NC machine tool 104 and the transfer device 105, respectively, based on operation completion signals that are directly exchanged without passing through the PLC 101. However, the same method can also be applied between two or more control devices communicating with the PLC 101 or between a control device controlled by the PLC 101 and another device.

In this embodiment, each control device operates based on the ON / OFF state of the operation completion signal. However, the operation completion signal is not limited to the ON / OFF state, and various signal forms may be applied. Can do.

According to the control device and the control method according to the present embodiment, since one control device directly receives the operation completion signal from the other control device, the PLC of this one control device has completed this operation. While the signal is being analyzed, a preparatory operation for operating the controlled device can be initiated. In this way, it is possible to effectively use the waiting time until the operation completion signal is received from the PLC, and to reduce time loss due to the fact that the controlled device cannot operate. Thereby, for example, when the PLC analyzes the operation completion signal and refers to the information from the server, the effect of reducing the time loss is increased. If this preparatory operation is completed before receiving the operation completion signal from the PLC, the operation waits until the operation completion signal is received from the PLC, and the operation completion signal is not received from the PLC even after a predetermined time has elapsed. Can stop the operation of the controlled device. Therefore, it is possible to guarantee a function for controlling a PLC production system equivalent to the conventional one.

According to the production system and the communication method according to the present embodiment, since one control device directly receives an operation completion signal from the other control device, the PLC of this one control device has completed this operation. While the signal is being analyzed, a preparatory operation for operating the controlled device can be initiated. In this way, the waiting time until the control device receives the operation completion signal from the PLC is effectively utilized, and the time loss due to the fact that the controlled device cannot operate is reduced, thereby reducing the tact time in the entire production system. be able to. Thereby, for example, when the PLC analyzes the operation completion signal and refers to the information from the server, the effect of reducing the time loss is increased. If this preparatory operation is completed before receiving the operation completion signal from the PLC, the operation waits until the operation completion signal is received from the PLC, and the operation completion signal is not received from the PLC even after a predetermined time has elapsed. Can stop the operation of the controlled device. Therefore, it is possible to guarantee a function for controlling a PLC production system equivalent to the conventional one.

Embodiment 2.
A second embodiment according to the present invention will be described with reference to FIGS. Here, parts that are the same as or equivalent to the configuration of the production system shown in FIGS. FIG. 6 is a diagram illustrating a configuration of a production system according to the second embodiment.

The PLC 800 controls a group of production systems 804. The PLC 101 in the first embodiment outputs the same operation completion signal when receiving the operation completion signal, but the PLC 800 in the present embodiment analyzes the operation completion signal when receiving the operation completion signal. The command signal is output based on the above. Reference numeral 801 denotes an NC device that controls the NC machine tool 104. MC 802 is an MC and controls the transport device 105. The NC device 801, MC 802, device 303, and network unit 304 can communicate with each other not only with the PLC 800 via the bus 111. Hereinafter, in order to simplify the description, communication of control signals among the PLC 800, the NC device 801, and the MC 802 will be described.

FIG. 7 (i) shows an operation performed by the PLC 800, the NC device 801, and the MC 802 in the production system 804 according to the present embodiment shown in FIG. It is a figure which shows the flow of. When the transfer device 105 completes the workpiece loading, the MC 802 outputs a loading completion signal to the PLC 800 and the NC device 801. Next, the NC device 801 starts machining preparation based on the input carry-in completion signal, and waits until a command signal is input from the PLC 800 when the preparation is completed. On the other hand, the PLC 800 analyzes the input carry-in completion signal and, when the NC machine tool 104 determines that the machining can be started, outputs a command signal for starting the machining to the NC device 801.

After confirming the machining start command signal input by the PLC 800, the NC device 801 causes the NC machine tool 104 to start machining. However, although not shown, if the NC machine tool 104 determines that machining should not be started as a result of analyzing the carry-in completion signal inputted by the PLC 800, it is for stopping the operation of the NC machine tool 104. A command signal is output to the NC device 801. After confirming the operation stop command signal input by the PLC 800, the NC device 801 stops the NC machine tool 104 without causing the NC machine tool 104 to start machining.

FIG. 7 (ii) shows an operation performed by the PLC 800, the NC device 801, and the MC 802 in the production system 804 according to the present embodiment shown in FIG. 6 from the completion of the processing of the workpiece to the start of unloading. It is a figure which shows the flow of. When the NC machine tool 104 completes the machining of the workpiece, the NC device 801 outputs a machining completion signal to the PLC 800 and the MC 802. Next, the MC 802 starts unloading preparation based on the input processing completion signal, and waits until a command signal is input by the PLC 800 after completing the preparation. On the other hand, the PLC 800 analyzes the input processing completion signal and outputs a signal for starting the unloading to the MC 802 if the transfer device 105 determines that the unloading may be started.

MC 802 confirms the carry-out start command signal input by PLC 800 and then causes carry device 105 to start carry-out. However, although not shown in the figure, if the processing completion signal inputted by the PLC 800 is analyzed, if it is determined that the transport device 105 should not start unloading, a command signal for stopping the operation of the transport device 105 Is output to the MC 802. After confirming the operation stop command signal input by the PLC 800, the MC 802 stops the transport device 105 without causing the transport device 105 to start unloading.

FIG. 8 is a diagram illustrating an internal configuration of the NC apparatus 801 according to the second embodiment. The signal processing unit 1003 processes an operation completion signal received from the PLC 800 and MC 802 via the I / F unit 212. The signal processing unit 1003 includes a signal receiving unit 1000, a controlled device starting unit 1001, and a signal matching unit 1002. Hereinafter, as shown in FIG. 7 (i), operations performed by the signal receiving unit 1000, the controlled device starting unit 1001, and the signal matching unit 1002 from the completion of loading of the workpiece to the start of machining will be described. To do.

The signal receiving unit 1000 receives a carry-in completion signal output from the MC 802 to the MC I / F unit 202 and a command signal output from the PLC 800 to the PLC I / F unit 201. The controlled device activation unit 1001 starts the operation of the NC machine tool 104 based on the carry-in completion signal received by the signal receiving unit 1000.

FIG. 9 is a flowchart illustrating a procedure of processes performed by the signal receiving unit 1000 and the controlled device activation unit 1001. First, the signal receiving unit 1000 confirms whether a loading completion signal is input by the MC 802, that is, whether a loading completion signal corresponding to the MC 802 is ON or OFF (S801). If it is OFF, the process is terminated. If it is ON, the process proceeds to S802.

In (S802), the controlled device activation unit 1001 outputs (turns on) a program execution notification signal to the PLC 800 and MC 802 via the PLC I / F unit 201 and the MC I / F unit 202, and the process proceeds to S803. move on. This program execution notification signal notifies the PLC 800 and MC 802 whether the machining program is being executed (ON) or stopped (OFF). Each control device can appropriately execute necessary processing based on the turned-on program execution notification signal. Note that this step S802 is optional, and if omitted, the process proceeds directly to step S803.

In (S803), the controlled device activation unit 1001 notifies the machining program analysis unit 206 that the carry-in completion signal corresponding to the MC 802 has been turned ON. This notification may be performed by a program execution notification signal that is turned on to the PLC 800 and the MC 802. Then, based on this notification, the machining program analysis processing unit 206 selects a machining program to be executed next by the NC machine tool 104, and acquires the selected machining program from the machining program storage unit 207. The controlled device activation unit 1001 starts executing the program acquired by the machining program analysis unit 206 and ends the process. When the execution of the program is started, the NC machine tool 104 starts machining preparation according to this program. When the preparation for machining is completed, it waits until a command signal is input by the PLC 800.

Here, the carry-in completion signal corresponding to MC 802 is normally turned on before the command signal input by PLC 800. This is because the MC 802 can turn on the carry-in completion signal immediately after the carry-in is completed, but the PLC 800 takes time to analyze the carry-in completion signal before turning on the command signal. On the other hand, when a command signal is input by the PLC 800 before the carry-in completion signal corresponding to the MC 802 is turned ON, the signal verification unit 1002 described later with reference to FIG. You may control NC machine tool 104 according to this command signal, without waiting for it to turn on.

The signal receiving unit 1000 can hold the state of the carry-in completion signal corresponding to the MC 802, and can also hold the state of the command signal of the PLC 800 by confirming whether the PLC 800 has turned on the command signal. The signal receiving unit 1000 and the controlled device activation unit 1001 always repeat S801 to S803.

When the PLC 800 outputs a command signal, the signal verification unit 1002 controls the NC machine tool 104 according to the command signal.

FIG. 10 is a flowchart showing a procedure of processing performed by the signal matching unit 1002. First, the signal verification unit 1002 confirms the state of the carry-in completion signal corresponding to the MC 802 (S901). If it is ON, the process proceeds to S902. At this time, the NC machine tool 104 has started machining preparation through S803. If it is OFF, the process is terminated. Here, when the signal receiving unit 1000 holds the state of the carry-in completion signal corresponding to the MC 802 and also confirms whether the PLC 800 has turned on the command signal, the command signal of the PLC 800 is also held. The unit 1002 can confirm the state of the carry-in completion signal and the command signal from the signal receiving unit 1000. Alternatively, similarly to the signal receiving unit 1000, the carry-in completion signal and the command signal may be directly received via the PLC I / F unit 201 and the MC I / F unit 202.

In (S902), the state of the command signal of PLC 800 is confirmed. If it is ON, the process proceeds to S903. If it is OFF, the process is terminated. At this time, the PLC 800 command signal can include information indicating that it corresponds to the carry-in completion signal corresponding to the MC 802. In this case, the signal verification unit 1002 can determine whether or not the command signal of the PLC 800 corresponds to a carry-in completion signal corresponding to the MC 802 by comparing them.

In (S903), it is confirmed whether the command signal of the PLC 800 is a “command for continuing program execution” or a “command for stopping program execution”. If it is a “command to continue program execution”, the process proceeds to S904. If it is “command to stop program execution”, the process proceeds to S905.

In (S904), execution of the machining program is continued and the process is terminated. As a result, the NC machine tool 104 starts machining after completing the machining preparation when the machining preparation is not completed, and immediately starts machining when waiting for the completion of the machining preparation. In (S905), the execution of the machining program is stopped, and the process proceeds to S906. As a result, the NC machine tool 104 stops without starting machining. In (S906), the program execution notification signal turned on by the signal receiving unit 1000 is turned off, and the process ends. As a result, the PLC 800 or MC 802 is notified that the execution of the machining program is being stopped. The signal matching unit 1002 always repeats S901 to S906.

The flow in FIG. 10 is based on the premise that the loading completion signal of MC 802 is turned on before the command signal of PLC 800. However, in rare cases, if any abnormality occurs in the MC 802 itself or the bus 111 between the MC 802 and the NC 801, the command signal of the PLC 800 may be turned on before the carry-in completion signal of the MC 802. In consideration of this, the flow of FIG. 10 shows that when the command completion signal of the PLC 800 is turned on before the carry-in completion signal of the MC 802, the command of the PLC 800 is not waited until the carry-in completion signal of the MC 802 is turned on. The flow may be such that the NC machine tool 104 is controlled according to the signal.

In the above description, as shown in FIG. 7 (i), the operation performed by the NC apparatus 801 from the completion of the workpiece loading to the start of machining has been described. On the other hand, as shown in FIG. 7 (ii), the MC 802 has the same internal configuration as the NC device 801 and performs the same operation from the completion of the processing of the workpiece to the start of unloading. The operation completion signal at this time is a machining completion signal.

Further, in the present embodiment, a method has been described in which the MC 802 and the NC device 801 start the operations of the NC machine tool 104 and the transfer device 105, respectively, based on operation completion signals that are directly exchanged without passing through the PLC 800. However, a similar method can be applied between any two or more devices controlled by PLC 800.

Further, the command signal of the PLC 800 is not limited to the program execution continuation / stop signal, and any command signal is possible, and the control device that has received the command signal can control the controlled device according to each command signal.

According to the control device and the control method according to the present embodiment, since one control device directly receives the operation completion signal from the other control device, the PLC of this one control device has completed this operation. While the signal is being analyzed, a preparatory operation for operating the controlled device can be initiated. In this way, it is possible to effectively utilize the waiting time until the command signal is received from the PLC, and to reduce time loss due to the fact that the controlled device cannot operate. Thereby, for example, when the PLC analyzes the operation completion signal and refers to the information from the server, the effect of reducing the time loss is increased. Further, even if this preparatory operation is completed, it waits until a command signal is received from the PLC, and when a command signal is received from the PLC, the operation of the controlled device can be continued / stopped according to the command signal. Since the PLC according to the present embodiment outputs not only the operation of the controlled device but also a command signal such as a stop, the PLC can be immediately executed without waiting for a signal from the PLC for a predetermined time as in the first embodiment. In addition, the operation of the controlled device can be stopped. Therefore, it is possible to guarantee a function for controlling a PLC production system equivalent to or higher than that of the conventional one.

According to the production system and the communication method according to the present embodiment, since one control device directly receives an operation completion signal from the other control device, the PLC of this one control device has completed this operation. While the signal is being analyzed, a preparatory operation for operating the controlled device can be initiated. In this way, the waiting time until the control device receives the command signal from the PLC is effectively used, and the time loss due to the fact that the controlled device cannot operate is reduced, thereby reducing the tact time in the entire production system. Can do. Thereby, for example, when the PLC analyzes the operation completion signal and refers to the information from the server, the effect of reducing the time loss is increased. Further, even if this preparatory operation is completed, it waits until a command signal is received from the PLC, and when a command signal is received from the PLC, the operation of the controlled device can be continued / stopped according to the command signal. Since the PLC according to the present embodiment outputs not only the operation of the controlled device but also a command signal such as a stop, the PLC can be immediately executed without waiting for a signal from the PLC for a predetermined time as in the first embodiment. In addition, the operation of the controlled device can be stopped. Therefore, it is possible to guarantee a function for controlling a PLC production system equivalent to or higher than that of the conventional one.

In addition, as a development example of the present embodiment, an example in which the present embodiment is combined with the first embodiment will be described with reference to FIG. The signal matching unit 1002 described with reference to FIG. 10 has to wait until the command completion signal from the PLC 800 is turned on after the carry-in completion signal from the MC 802 is turned on. If this waiting time is too long, the tact time may become long. In order to solve this problem, it is advisable to set an upper limit of this waiting time as in the first embodiment.

FIG. 11 is a flowchart showing a procedure of processing performed by the signal matching unit 1002 according to the development example of the second embodiment. First, the signal verification unit 1002 confirms the state of the carry-in completion signal corresponding to the MC 802 (S1001). If it is ON, the process proceeds to S1002. If it is OFF, the process is terminated. Here, when the signal receiving unit 1000 holds the state of the carry-in completion signal corresponding to the MC 802 and also confirms whether the PLC 800 has turned on the command signal, the command signal of the PLC 800 is also held. The unit 1002 can confirm the state of the carry-in completion signal and the command signal from the signal receiving unit 1000. Alternatively, similarly to the signal receiving unit 1000, the carry-in completion signal and the command signal may be directly received via the PLC I / F unit 201 and the MC I / F unit 202.

In (S1002), next, the time measuring unit 210 provided in the signal verification unit 1002 is activated, and the process proceeds to S1003. This time measuring device 210 measures the time from the time of activation. In (S1003), the collation allowable time parameter is read from the parameter storage unit 208, and the process proceeds to S1004. The collation allowable time parameter is set in advance by the user of the NC device 801 using the display device 209.

In (S1004), the time value measured by the time measuring device 210 is compared with the time value represented by the time parameter read from the parameter storage unit 208. When the time value measured by the time measuring device 210 is equal to or less than the time value represented by the collation allowable time parameter, the process proceeds to S1005. When the time value measured by the time measuring device 210 is larger than the time value represented by the collation allowable time parameter, the process proceeds to S1008.

In (S1005), the state of the command signal of PLC 800 is confirmed. If it is ON, the process proceeds to S1006. If it is OFF, the process returns to S1004. At this time, the PLC 800 command signal can include information indicating that it corresponds to the carry-in completion signal corresponding to the MC 802. In this case, the signal verification unit 1002 can determine whether or not the command signal of the PLC 800 corresponds to a carry-in completion signal corresponding to the MC 802 by comparing them.

In (S1006), it is confirmed whether the command signal of PLC 800 is a “command for continuing program execution” or a “command for stopping program execution”. If it is “an instruction to continue program execution”, the process proceeds to S1007. If it is a “command to stop program execution”, the process proceeds to S1008.

In (S1007), execution of the machining program is continued and the process is terminated. As a result, the NC machine tool 104 starts machining after the machining preparation is completed when the machining preparation is not completed, and starts machining immediately when waiting for the completion of the machining preparation. In (S1008), execution of the machining program is stopped, and the process proceeds to S1009. As a result, the NC machine tool 104 stops without starting machining. In (S1009), the program execution notification signal turned on by the signal receiving unit 1000 is turned off, and the process ends. As a result, the PLC 800 or MC 802 is notified that the execution of the machining program is being stopped. The signal matching unit 1002 always repeats S1001 to 1009.

Further, the command signal of the PLC 800 is not limited to the program execution continuation / stop signal, and any command signal is possible, and the control device that has received the command signal can control the controlled device according to each command signal.

1 is a diagram illustrating a configuration of a production system according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating an operation flow of the production system according to the first embodiment. It is a figure which shows the internal structure of NC apparatus in Embodiment 1. FIG. 3 is a flowchart illustrating a procedure of processes performed by a signal reception unit and a controlled device activation unit in the first embodiment. 3 is a flowchart illustrating a procedure of processing performed by a signal matching unit according to Embodiment 1. It is a figure which shows the structure of the production system which concerns on Embodiment 2. FIG. FIG. 10 is a diagram showing an operation flow of the production system according to the second embodiment. It is a figure which shows the internal structure of NC apparatus in Embodiment 2. FIG. 10 is a flowchart illustrating a procedure of processes performed by the signal reception unit and the controlled device activation unit according to the second embodiment. 10 is a flowchart illustrating a procedure of processing performed by a signal matching unit according to Embodiment 2. 10 is a flowchart illustrating a procedure of processing performed by a signal matching unit according to a development example of the second embodiment. It is a figure which shows the structural example of the conventional production system. It is a figure which shows the example of the flow of operation | movement of the conventional production system.

Explanation of symbols

101, 800 PLC
102, 301, 801 NC device 103, 302, 802 MC
104 NC machine tool 105 Conveying device 106, 110, 300 Production system 107, 303 Device 108, 304 Network unit 109 Server 111 Bus 112, 116 Servo amplifier 113 Main shaft amplifier 114, 117 Servo motor 115 Main shaft motor 201 PLC I / F section 202 MC I / F unit 203, 1000 Signal receiving unit 204, 1001 Controlled device activation unit 205, 1002 Signal verification unit 206 Processing program analysis unit 207 Processing program storage unit 208 Parameter storage unit 209 Display device 210 Time measuring device 212 I / F unit 213, 1003 Signal processing unit 214 Analysis unit 215 Storage unit

Claims (16)

In the control device connected to the PLC and controlling the operation of the controlled device based on the signal from the PLC,
Second to force out in response to the first signal and the first signal is the PLC receiving the first signal indicative of the operation completion of said external apparatus the external device connected to the PLC outputs a signal receiving unit for receiving the signals and, the,
A controlled device starting unit for starting the operation of the controlled device based on the first signal received by the signal receiving unit ;
A signal collating unit that collates the first signal and the second signal, and continues or stops the operation of the controlled device based on the collation result;
A control device comprising: The second signal is identical to the first signal;
The control device according to claim 1, wherein the signal collating unit collates an ON / OFF state of the first signal with an ON / OFF state of the second signal. The second signal is a command signal related to the operation of the controlled device,
3. The control device according to claim 1, wherein the signal collating unit discriminates the content of the command signal and controls the operation of the controlled device based on the discriminated result. The signal collating unit stops the operation of the controlled device when it does not receive one of the first signal and the second signal even after a predetermined time has elapsed after receiving one of the first signal and the second signal. The control device according to claim 1. A plurality of control devices;
A PLC communicating with each of the control devices;
In a production system consisting of
The controller is
A first signal indicating an operation completion of the external apparatus other of said control device outputs, and a second signal said first of said PLC received a signal to force out in response to the first signal A signal receiving unit for receiving;
A controlled device starting unit for starting the operation of the controlled device based on the first signal received by the signal receiving unit ;
A signal collating unit that collates the first signal and the second signal, and continues or stops the operation of the controlled device based on the collation result;
A production system characterized by comprising: The second signal is identical to the first signal;
The production system according to claim 5, wherein the signal collating unit collates an ON / OFF state of the first signal with an ON / OFF state of the second signal. The second signal is a command signal related to the operation of the controlled device,
The production system according to claim 5 or 6, wherein the signal verification unit determines the content of the command signal and controls the operation of the controlled device based on the determined result. The signal collating unit stops the operation of the controlled device when it does not receive one of the first signal and the second signal even after a predetermined time has elapsed after receiving one of the first signal and the second signal. The production system according to any one of claims 5 to 7. In a control method for controlling the operation of a controlled device based on a signal from a PLC,
A first signal receiving step for receiving a first signal indicating completion of operation of the external device output by the external device connected to the PLC ;
A second signal receiving step of the PLC which receives the first signal receives the second signal to force out in response to the first signal,
A controlled device starting step for starting the operation of the controlled device based on the first signal received in the signal receiving step ;
A signal verification step of verifying the first signal and the second signal;
A verification result processing step of continuing or stopping the operation of the controlled device based on the result of verification in the signal verification step;
A control method characterized by comprising: The second signal is identical to the first signal;
The control method according to claim 9, wherein the signal collating step collates an ON / OFF state of the first signal with an ON / OFF state of the second signal. The second signal is a command signal related to the operation of the controlled device,
The signal verification step determines the content of the command signal,
The control method according to claim 9 or 10, wherein the collation result processing step controls the operation of the controlled device based on a result determined in the signal collation step. The signal collating step stops the operation of the controlled device when a predetermined time has elapsed after receiving one of the first signal and the second signal, and the other is not received. The control method according to any one of claims 9 to 11. A first signal receiving step for receiving a first signal indicating completion of operation of the external device output by another control device;
A second signal receiving step of receiving a second signal PLC which receives the first signal is the power output in response to the first signal,
A controlled device starting step for starting the operation of the controlled device based on the first signal received in the first signal receiving step ;
A signal verification step of verifying the first signal and the second signal;
A verification result processing step of continuing or stopping the operation of the controlled device based on the result of verification in the signal verification step;
A communication method between a plurality of control devices communicating with the PLC. The second signal is identical to the first signal;
The communication method according to claim 13, wherein the signal collating step collates an ON / OFF state of the first signal with an ON / OFF state of the second signal. The second signal is a command signal related to the operation of the controlled device,
The signal verification step determines the content of the command signal,
15. The communication method according to claim 13, wherein the collation result processing step controls the operation of the controlled device based on the result determined in the signal collation step. The signal collating step stops the operation of the controlled device when a predetermined time has elapsed after receiving one of the first signal and the second signal, and the other is not received. The communication method according to any one of claims 13 to 15.

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