JP2024053905A - Programmable logic controller controlled production system - Google Patents

Abstract

[Problem] To easily collect data signals other than predetermined data signals from a PLC. [Solution] An aseptic filling machine is equipped with multiple production equipment, each of which is controlled by a PLC. The multiple PLCs are connected to each other by a shared communication line 25, and the data signals output from each PLC based on a program given to each PLC are shared by each PLC via the shared communication line 25. Furthermore, external connection lines 32, 31, 33, which are communication lines separate from the shared communication line 25, are connected to three of the multiple PLCs, PLCs 11, 12, 20, for reading out data signals from the PLCs 11, 12, 20. [Selected Figure] Figure 1

Description

This invention relates to a production system that is equipped with a programmable logic controller (PLC) and controlled by the PLC.

Patent document 1 discloses a production line equipped with multiple pieces of production equipment, each of which is controlled by a PLC.

JP 2006-113965 A

The PLC stores the sequential operation of production equipment and controls its operation. It can also control production equipment according to the operating status of other production equipment. By providing data signals indicating, for example, the operating status of each piece of production equipment to the signal lines connecting the PLCs, it is also possible to control the entire production equipment, such as temporarily suspending the operation of downstream production equipment in response to an abnormality in upstream production equipment on the production line (sharing of data signals).

The shared data signals are output from the PLC according to a program given to the PLC and supplied to the signal lines connecting the PLCs. In other words, the data signals to be supplied to the signal lines connecting the PLCs must be determined in advance in the PLC program. When attempting to acquire (collect) a type of data signal other than the predetermined data signals, the PLC program must be rewritten so that it outputs the corresponding data signal. Rewriting of the PLC program must be done when the manufacturing equipment is stopped, and is generally done by a person in charge at the manufacturing equipment manufacturer. Currently, collecting data signals other than the predetermined data signals is time-consuming and labor-intensive.

The purpose of this invention is to make it possible to easily collect data signals other than predetermined data signals from a PLC.

The PLC-controlled production system of the present invention is a PLC-controlled production system that includes multiple pieces of production equipment, each of which is controlled by a programmable logic controller (hereinafter referred to as a PLC), and is characterized in that it includes a shared communication line that connects the multiple PLCs together and shares among the PLCs data signals output from each PLC based on a program provided to each PLC, and an external connection line that is a communication line separate from the shared communication line and is connected to at least one of the multiple PLCs and is used to read out data signals from the PLC.

According to this invention, desired data signals can be collected (obtained) from a PLC through an external connection line without rewriting the PLC's program. The external connection line does not necessarily need to be connected to all of the multiple PLCs that make up the production system; it is sufficient to connect it only to the PLC of the production equipment that receives the data signals that need to be collected (and subsequently investigated, analyzed, etc.).

In one embodiment, the PLC control system includes a gateway device connected to the external connection line and equipped with a command transmission means for transmitting a data read command to the PLC to which the external connection line is connected. By issuing a data read command from the gateway device to the PLC, it is possible to identify the production equipment to which the data read command should be issued when the external connection lines are connected to the PLCs of multiple production equipment, and to issue a data read command to the PLC of the identified production equipment.

Preferably, the system further includes an operation terminal that instructs the gateway device to send a data read command. The operation terminal can manage the collection of data signals.

FIG. 1 is a network configuration diagram of a sterile filling machine. FIG. 2 is a block diagram showing the electrical configuration of a PLC. 4 shows an example of a data signal stored in the memory of the PLC. 1 shows a flow of a data signal read command and a data signal read based on the command, which are transmitted and received through a gateway device.

Figure 1 shows the network configuration diagram of a sterile filling machine.

The aseptic filling machine performs multiple processes such as blending, extraction, liquid processing, material supply, container forming, filling, labeling, inspection, caser, and palletizer, and is equipped with multiple production devices to perform each process. Piping, conveying devices, sterilization devices, etc. connecting each production device are also provided. In addition, the aseptic filling machine also includes multiple tanks such as a balance tank, aseptic surge tank, and head tank. Each of these multiple production equipment 1 to 10 (including production equipment, piping, conveying devices, sterilization devices, tanks, etc.) is equipped with a PLC (programmable logic controller) 11 to 20. For convenience, Figure 1 illustrates 10 production equipment 1 to 10 as the production equipment that makes up the aseptic filling machine, but the number of production equipment may be more or less than this.

PLCs 11-20 control production equipment 1-10, generating and outputting output data signals based on input data signals. Condition control and sequence control are also performed by PLCs 11-20. By sequentially controlling the operation of production equipment 1-10 by PLCs 11-20, for example, if the aseptic filling machine is a type that bottles beverages, it will automatically perform processes such as mixing ingredients, sterilizing the beverage, forming the bottles, sterilizing the bottle mouths, filling the bottles, sterilizing the caps, capping, labeling, inspection, boxing, and transportation.

The production equipment 1-10 equipped with PLCs 11-20 are connected to a shared communication line 25. The shared communication line 25 is a communication line, such as an optical cable, and data signals (information) for operating each of the production equipment 1-10 are sent through the shared communication line 25. For example, information on the type of beverage currently being manufactured in the aseptic filling device, operation information of the production equipment 1-10, number of bottles produced, number of bottles rejected, error information in the event of an abnormality, sensor information that affects other production equipment, etc. are given to the PLCs 11-20 of each production equipment 1-10 through the shared communication line 25. The PLCs 11-20 share the status of each production equipment 1-10 sent through the shared communication line 25, and these shared data signals are also used to control the operation of the production equipment 1-10.

In addition to the shared communication line 25, external connection lines (e.g., optical cables) 31, 32, 33 different from the shared communication line 25 are connected to the three PLCs 11, 12, 20 of the production equipment 1, 2, and 10. The PLCs 11, 12, 20 are connected to the gateway device 26 via the external connection lines 31, 32, 33, and the gateway device 26 is further connected to the operation terminal 51 via a network (e.g., the Internet) 35. Based on an instruction from the operation terminal 51, the gateway device 26 can obtain data signals from the PLCs 11, 12, 20. The number of PLCs connected to the gateway device 26 may be more or less than three. The gateway device 26 may be, for example, a personal computer, a router, or a dedicated IoT gateway device, and has a function of reading data stored in the memory (described later) of the PLCs 11, 12, 20 (controlling the PLC to read data from the memory) and uploading (transmitting) the read data.

Figure 2 is a block diagram showing the electrical configuration of PLC 11. The other PLCs 12 to 20 also have the same electrical configuration as PLC 11 shown in Figure 2.

The PLC 11 has a calculation unit 41, a memory 42, a communication unit 43, an input unit 44, and an output unit 45.

The calculation unit 41 controls the overall operation of the PLC 11, and controls the production equipment according to a program created by the user.

Input devices such as switches, buttons, and various sensors are connected to the input unit 44, and information from the input devices is input.

Output devices such as relays, indicator lights, and motors are connected to the output unit 45, and the results of the program's calculations are transmitted to the output devices.

The memory 42 has memory areas for storing various data (data signals) handled by the PLC 11, and the areas are divided according to the type of data. For example, program data created by the user is stored in the user program area, and data related to the ON/OFF of input/output devices is stored in the I/O memory area.

The communication unit 43 controls the input and output of data signals transmitted and received through the shared communication line 25 and the external connection line 32. The data signals received by the communication unit 43 are also stored in the memory 42 (I/O memory area) and can be used by the calculation unit 41 to control the production equipment.

Data signals from input devices connected to the input unit 44 and data signals received by the communication unit 43 are stored in the I/O memory area of the memory 42. The calculation unit 41 creates control data for controlling output devices based on the data signals stored in the I/O memory area, in accordance with the program stored in the user program area of the memory 42. The operation of the production equipment is controlled by providing the control data to the production equipment (relays, displays, motors, etc. equipped in the production equipment) via the output unit 45.

Figure 3 shows a portion of the data signal (information) stored in the I/O memory area of memory 42 of PLC 11.

As described above, the data signals stored in the I/O memory area of memory 42 are data signals input from an input device connected to input unit 44 and data signals received by communication unit 43. In FIG. 3, among the data signals stored in the I/O memory area, data signals received by communication unit 43 are marked with a circle. This circled data, in this case product type information, operation information, counter information, and error information, is also sent (shared) to PLCs 12 to 20 of other production equipment via the shared communication line 25 described above. This makes it possible to control operations such as stopping the operation of one production equipment when an abnormality occurs in the other production equipment.

In addition to data signals shared with other production equipment via the shared communication line 25, the memory 42 also stores data signals relating to details of the operating status of the production equipment that are not output to the shared communication line 25 (not shared between PLCs), such as data signals representing instrument information (temperature, pressure, concentration, flow rate, etc.) and setting information (frequency, timing control parameters, etc.). In Figure 3, data signals that are not output to the shared communication line 25 but are acquired by the PLC and stored in the memory 42 are indicated by "-".

The type of data signal shared with other production equipment via the shared communication line 25 is determined by the program of the PLC 11. By changing the program of the PLC 11, it is possible to change (add, delete) the type of data signal shared with other production equipment via the shared communication line 25.

A gateway device 26 and an external connection line 32 are used to remotely acquire data signals stored in the memory 42 of the PLC 11 that are not output (transmitted or received) to the shared communication line 25 (Figure 1).

Figure 4 is a block diagram showing the process flow when acquiring an arbitrary data signal from the memory 42 of the PLC 11 through the gateway device 26.

A data read command is given from the operation terminal 51 to the gateway device 26 via the network 35. The read command includes information that identifies the production equipment (here, production equipment 1) from which the data signal is to be read and information that identifies the type of data signal to be acquired.

The gateway device 26 transmits a read command for a specific data signal to a specific production facility, in this case the PLC 11 of the production facility 1, in accordance with the read command. The read command from the gateway device 26 is given to the PLC 11 via the external connection line 32. The read command is received by the communication unit 43 of the PLC 11, and the requested data signal is read from the memory 42 by the calculation unit 41 of the PLC 11. The data signal read from the memory 42 is output from the communication unit 43 to the external connection line 32 and transmitted to the operation terminal 51 via the gateway device 26 and the network 35.

The external connection line 32 may be connected to one PLC or to all PLCs. However, it is not necessarily necessary to connect the external connection line 32 to all PLCs 11 to 20. For example, if the external connection line 32 is connected to a PLC of a production facility that stores data signals related to the quality of products manufactured by a sterile filling machine in memory 42, the product quality can be checked remotely.

1 to 10 Production facilities
11 to 20 P.L.C.
25 Shared Communication Lines
26 Gateway Device
31, 32, 33 External connection lines
35 Network
42 Memory
51 Operation terminal

Claims (3)

A production system controlled by a programmable logic controller (hereinafter referred to as PLC), comprising a plurality of pieces of production equipment, each of which is controlled by a PLC,
a shared communication line for connecting the plurality of PLCs to each other and for sharing among the PLCs a data signal output from each PLC based on a program given to each PLC; and an external connection line which is a communication line separate from the shared communication line and is connected to at least one of the plurality of PLCs and for reading out the data signal from the PLC;
A PLC-controlled production system equipped with a gateway device including a command transmission means connected to the external connection line and transmitting a data read command to the PLC to which the external connection line is connected;
2. The PLC-controlled production system according to claim 1. The gateway device further includes an operation terminal for instructing the gateway device to transmit a data read command.
3. A PLC-controlled production system according to claim 2.

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