Programmable controller and manufacturing system

Abstract

A PLC (10A) is provided with: a main unit (11) that executes a control program for controlling a manufacturing device; and a plurality of extension units including, in the control program, a system configuration setting that defines a connection configuration of the extension units with respect to the main unit, the main unit comparing the connection configuration of the extension units defined in the system configuration setting with a connection configuration of the extension units on an actual machine when the main unit is started up, a unit number of an extension unit that exists in the system configuration setting and does not exist in the actual device is set as an empty number, and a command in the control program to which the unit number set as the empty number is set is invalidated.

Description

Technical Field

[0001] The present invention relates to a programmable logic controller and a manufacturing system that operate using a control program. Background Art

[0002] In a manufacturing site such as a factory, a programmable logic controller (PLC) (also called a programmable logic controller) is used as a control device that acquires signals from various sensors and controls actuators and the like based on the acquired signals.

[0003] For this PLC, it is possible to expand the number of input / output points of signals, expand functions for communicating with other control devices, etc., in accordance with the control scale and required functions of the manufacturing device. This expansion of functions is carried out by connecting input / output units, communication units, and other expansion units in the required number to the main unit that executes a control program represented by a ladder diagram program.

[0004] The control program used in the main unit includes a system structure setting that has connection position information on which expansion unit is connected to the main unit as which unit number. In addition, the control program also includes expansion programs for controlling each expansion unit, and these expansion programs operate based on the connection position information included in the system structure setting.

[0005] In a manufacturing site, sometimes the same product is manufactured in multiple types in order to respond to product customization, etc. At this time, the manufacturer of the manufacturing device sometimes manufactures multiple types of manufacturing devices that use the same PLC but have different structures of expansion units connected to the main unit. In this case, due to the difference in the connection structure of the expansion units, the manufacturer creates the same control program for each manufacturing device. And when the common part of the control program needs to be changed, the manufacturer makes the same correction to multiple programs, so it becomes a cause of a decrease in development efficiency and a decrease in maintainability.

[0006] To address such a problem, the PLC of Patent Document 1 preliminarily sets the connection for a predetermined expansion unit to be used in the future or in other manufacturing devices in the system structure setting of the control program, and then sets the unit number used to identify the connection position of the expansion unit to an empty number. As a result, the PLC of Patent Document 1 does not cause the control program associated with the unit number set as an empty number to operate. In addition, when the PLC of Patent Document 1 actually connects the expansion unit that was previously set as an empty number to the actual machine, it automatically cancels the empty number state and automatically takes effect on the control program associated with the unit number of the connected expansion unit. As a result, the PLC of Patent Document 1 can use the same control program regardless of whether or not a unit that is preliminarily set as an empty number is connected, and can achieve the integration of control programs between multiple manufacturing devices with different connection structures of the expansion units.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-52672 Summary of the invention

[0008] However, in the technology of the above-mentioned Patent Document 1, it is sufficient to set a blank number in advance for the change of the expansion unit within the predetermined assumption used in the future or in other manufacturing devices, but when an unexpected change of the expansion unit is required, the control program needs to be corrected. Therefore, in the technology of the above-mentioned Patent Document 1, there is a problem that when an unexpected change of the expansion unit is required, a new control program derived from the control program commonly used among a plurality of manufacturing devices of different types needs to be created.

[0009] The present invention is proposed in view of the above situation, and its purpose is to obtain a programmable controller that can be used without modifying the control program commonly used among multiple manufacturing devices of different types even when an unexpected change of the expansion unit is required.

[0010] In order to solve the above problems and achieve the object, the programmable controller of the present invention has: a main unit that executes a control program for controlling a manufacturing apparatus; and a plurality of expansion units that can be connected to the main unit and are used for expanding the functions of the manufacturing apparatus. The control program includes a system structure setting for defining the connection structure of the expansion units relative to the main unit and a command for instructing the input / output of signals for the expansion units. The system structure setting includes a unit number for identifying the connection position of the expansion units relative to the main unit, and the command includes a parameter, i.e., a number setting parameter, for setting the unit number for determining which of the expansion units the signal input / output is to be made. When starting up, the main unit compares the connection structure of the expansion units defined in the system structure setting with the connection structure of the expansion units on the actual machine, sets the unit numbers of the expansion units that exist in the system structure setting but do not exist in the actual machine as null numbers, and invalidates the commands in which the unit numbers set as null numbers are set.

[0011] Effects of the Invention

[0012] The programmable controller according to the present invention has the following effect, that is, even in the case where changes other than those envisaged for the expansion units are required, it can be used without modifying the control program that is commonly used among a plurality of different types of manufacturing apparatuses. Description of the Drawings

[0013] Figure 1 It is a diagram showing the structure of a first manufacturing system having a first PLC according to Embodiment 1.

[0014] Figure 2 It is a diagram showing the structure of a second manufacturing system having a second PLC according to Embodiment 1.

[0015] Figure 3 It is a diagram showing an example of the system structure setting applied to the first and second PLCs according to Embodiment 1.

[0016] Figure 4 It is a diagram showing an example of the control program applied to the first and second PLCs according to Embodiment 1.

[0017] Figure 5 It is a diagram for explaining the first to fourth parameters of the control program applied to the first and second PLCs according to Embodiment 1.

[0018] Figure 6 It is a flowchart showing the operation processing flow of the second PLC according to Embodiment 1.

[0019] Figure 7It is a diagram for explaining the process in which the second PLC according to Embodiment 1 compares models.

[0020] Figure 8 It is a diagram showing the structure of a third manufacturing system having a third PLC according to Embodiment 2.

[0021] Figure 9 It is a flowchart showing the operation processing flow of the third PLC according to Embodiment 2.

[0022] Figure 10 It is a diagram showing an example of a first screen displayed by an engineering design tool on a display device according to Embodiment 3.

[0023] Figure 11 It is a diagram showing an example of a second screen displayed by an engineering design tool on a display device according to Embodiment 3.

[0024] Figure 12 It is a diagram showing an example of a third screen displayed by an engineering design tool on a display device according to Embodiment 3.

[0025] Figure 13 It is a diagram showing an example of the hardware structure of the control circuit included in the main unit according to Embodiments 1 to 4. Detailed Embodiments

[0026] Hereinafter, a programmable logic controller and a manufacturing system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0027] Embodiment 1

[0028] Figure 1 It is a diagram showing the structure of a first manufacturing system having a first PLC according to Embodiment 1. As the manufacturing system 101 of the first manufacturing system, there are a PLC engineering design tool 5 and a manufacturing device 1 as the first manufacturing device.

[0029] The manufacturing device 1 has sensors 31 and 32, other devices 21, an actuator 41, and a PLC 10A as the first PLC. The engineering design tool 5 is stored in a computer, and the computer is connected to the PLC 10A.

[0030] The PLC 10A has a main unit 11, an input unit 12, an output unit 13, an analog input unit 14, and a communication unit 15. The input unit 12, the output unit 13, the analog input unit 14, and the communication unit 15 are all expansion units. The expansion unit is a unit that can be installed on the main unit 11 or removed from the main unit 11 as needed for functional expansion of the manufacturing device 1.

[0031] A plurality of expansion units can be connected to the main unit 11. In the manufacturing apparatus 1, an input unit 12, an output unit 13, an analog input unit 14, and a communication unit 15 are respectively connected to the main unit 11.

[0032] The unit number of an expansion unit that is actually not connected to the main unit 11 among the expansion units whose connection structure is set for the main unit 11 by the engineering design tool 5 is a unit number determined to be an empty number. That is, even if the connection structure is set, the unit number of an expansion unit that is actually not connected to the main unit 11 is a unit number determined to be an empty number. The unit number is information for identifying the connection position of the expansion unit relative to the main unit 11. When there are N (N is a natural number) expansion units that can be connected to the main unit 11, and when M (M is a natural number less than or equal to N) expansion units are connected to the main unit 11, the unit numbers of (N - M) expansion units become empty numbers.

[0033] In the PLC 10A, the main unit 11 is connected to a computer that stores the engineering design tool 5. In addition, the input unit 12 is connected to the sensor 31, and the analog input unit 14 is connected to the sensor 32. In addition, the communication unit 15 is connected to the other device 21, and the output unit 13 is connected to the actuator 41.

[0034] The engineering design tool 5 is executed by a computer that stores the engineering design tool 5. The engineering design tool 5 makes various settings for the main unit 11 according to instructions from the user. In addition, the engineering design tool 5 creates a control program to be applied to the manufacturing apparatus 1 according to instructions from the user. This control program is also a program applied to the manufacturing apparatus 2 described later. That is, the control program created by the engineering design tool 5 is a program that is commonly used among a plurality of manufacturing apparatuses of different types (in Embodiment 1, the manufacturing apparatuses 1 and 2). The control program commonly used in the manufacturing apparatuses 1 and 2 is a control program obtained by integrating a control program that can be used in the manufacturing apparatus 1 and a control program that can be used in the manufacturing apparatus 2. The control program is a program for controlling the manufacturing apparatuses 1 and 2 and is executed by the main unit 11.

[0035] The control program created by the engineering design tool 5 includes a system structure setting, and this system structure setting has connection position information on which expansion unit is connected to the main unit 11 as which number. That is, the system structure setting is information that defines the connection structure of the expansion unit relative to the main unit 11.

[0036] The engineering design tool 5 writes the created control program into the main unit 11. In addition, the engineering design tool 5 reads out the unit numbers of the expansion units that have become empty numbers from the main unit 11 and displays them on a display device or the like.

[0037] A control program is written in the main unit 11, and the main unit 11 uses the control program to control the PLC 10A. When the power is turned on, the main unit 11 starts and parses the control program during the startup process.

[0038] The sensor 31 collects information from the first measurement object and sends a digital signal corresponding to the collected information to the input unit 12. The sensor 32 collects information from the second measurement object and sends an analog signal corresponding to the collected information to the analog input unit 14. The information collected by the sensors 31 and 32 is temperature, voltage, etc.

[0039] The input unit 12 receives the digital signal from the sensor 31 and inputs it to the main unit 11. The analog input unit 14 receives the analog signal from the sensor 32 and inputs it to the main unit 11.

[0040] The communication unit 15 performs communication with other devices 21. The communication unit 15 sends the data sent from the main unit 11 to other devices 21, receives the data sent from other devices 21, and sends it to the main unit 11. The other devices 21 are devices other than the PLC 10A.

[0041] The main unit 11 uses the digital signal sent from the input unit 12, the analog signal sent from the analog input unit 14, the data sent from the communication unit 15, and the control program to generate data for controlling the actuator 41. The main unit 112 sends the generated data to the output unit 13. The output unit 13 outputs the data sent from the main unit 11 to the actuator 41.

[0042] Figure 2 It is a diagram showing the structure of the second manufacturing system having the second PLC according to Embodiment 1. Figure 2 For each structural element of Figure 1 the structural elements that achieve the same functions as those of the manufacturing system 101 are labeled with the same reference numerals, and repeated descriptions are omitted. The manufacturing system 102 as the second manufacturing system has an engineering design tool 5 and a manufacturing device 2 as the second manufacturing device.

[0043] The manufacturing device 2 has a sensor 31, other devices 21, an actuator 41, and a PLC 10B as the second PLC. The engineering design tool 5 is stored in a computer, and the computer is connected to the PLC 10B.

[0044] The PLC 10B has a main unit 11, an input unit 12, an output unit 13, and a communication unit 15. That is, compared with the PLC 10A, the PLC 10B does not have an analog input unit 14, and the unit number of the analog input unit 14 is a null number. In the PLC 10B, the input unit 12, the output unit 13, and the communication unit 15 are all expansion units.

[0045] The main unit 11 of the PLC 10B has the same functions as the main unit 11 of the PLC 10A. The main unit 11 of the PLC 10B and the main unit 11 of the PLC 10A may also be main units of different types.

[0046] In a manufacturing site, sometimes the same products are manufactured in multiple types in order to handle product customization, etc. For example, the manufacturing device 1 manufactures the first product for which the first customization has been performed on the product, and the manufacturing device 2 manufactures the second product for which the second customization has been performed on the product. The first customization and the second customization can be any customization.

[0047] The first product manufactured by the manufacturing device 1 is a product manufactured by controlling the actuator 41 using an analog signal. The second product manufactured by the manufacturing device 2 is a product manufactured by controlling the actuator 41 without using an analog signal.

[0048] In this way, the manufacturing devices 1 and 2 are constituted by using main units 11 having the same functions, but the structures of the expansion units connected to the main unit 11 are different. By using multiple types of manufacturing devices 1 and 2, the manufacturing devices 1 and 2 manufacture multiple types of customized products.

[0049] In the first embodiment, the user does not need to set an empty number in the system structure setting within the control program in advance. The main unit 11 of the manufacturing devices 1 and 2 sequentially compares the connection structure included in the system structure setting at the time of starting the main unit 11 with the connection structure of the actual machine (hereinafter, sometimes referred to as the actual machine structure) from the connection position closer to the main unit 11 (the connection position on the front stage side when viewed from the main unit 11).

[0050] When the expansion unit exists in the system structure setting but does not exist in the connection structure of the actual machine, the main unit 11 automatically sets the unit number of the expansion unit as an empty number. In addition, the main unit 11 automatically invalidates the control program related to the expansion unit with the unit number set as an empty number. Thereby, the main unit 11 does not change the control program but still operates using the control program.

[0051] Here, examples of the system structure setting and the control program will be described. Figure 3 It is a diagram showing an example of the system structure setting applied to the first and second PLCs according to the first embodiment. In Figure 3 it shows the system structure setting 50 included in the control program.

[0052] In addition, here, the system structure setting 50 of the PLC 10B will be described. The system structure setting 50 is created using the engineering design tool 5 of the manufacturing system 101 or the manufacturing system 102.

[0053] The system structure setting 50 includes an expansion unit connection structure (expansion unit connection structure 51) and an assigned unit number (assigned unit number 52).

[0054] The expansion unit connection structure 51 is information indicating the connection structure of the expansion units within the PLC 10B. The assigned unit number 52 is the unit number assigned to each expansion unit for identifying the connection location.

[0055] In Figure 3 the expansion unit connection structure 51, it is shown that an input unit ( Figure 2 input unit 12) is connected at the connection location closest to the main unit ( Figure 2 main unit 11), and an output unit ( Figure 2 output unit 13) is connected at the second closest connection location. Additionally, in Figure 3 the expansion unit connection structure 51, it is shown that an analog input unit (analog input unit 14 not configured in Figure 2 ) is connected at the connection location third closest to the main unit, and a communication unit ( Figure 2 communication unit 15) is connected at the fourth closest connection location. The main unit, input unit, output unit, analog input unit, and communication unit in the expansion unit connection structure 51 respectively correspond to the main unit 11, input unit 12, output unit 13, analog input unit 14, and communication unit 15 described in Figure 1 . In addition, in the following description, the expansion unit connection structure 51 may sometimes be simply referred to as the connection structure.

[0056] In Figure 3 the assigned unit number 52, it is shown that the unit number U1 is assigned to the input unit and the unit number U2 is assigned to the output unit. Additionally, in Figure 3 the assigned unit number 52, it is shown that the unit number U3 is assigned to the analog input unit and the unit number U4 is assigned to the communication unit.

[0057] As Figure 2As shown, the PLC 10B is actually not connected to the analog input unit 14. In Embodiment 1, information indicating that the unit number U3 corresponding to the analog input unit 14 is an empty number is not stored in the system configuration setting 50 of the PLC 10B. In Embodiment 1, the main unit 11 of the PLC 10B detects the empty number by comparing the system configuration setting 50 with the actual machine structure, and the information of the empty number is read by the engineering design tool 5 and displayed on the monitoring screen (system configuration setting monitoring screen). In Figure 3 the unit number U3, which is an empty number, is shaded and illustrated.

[0058] Figure 4 FIG. is a diagram showing an example of a control program applied to the first and second PLCs according to Embodiment 1. In addition, here, the control program 60 applied to the PLC 10B will be described. The control program 60 is created using the engineering design tool 5 of the manufacturing system 101 or the manufacturing system 102 and is used for the manufacturing devices 1 and 2.

[0059] Figure 4 The control program 60 is a program for the expansion unit. In Figure 4 it shows the case where the control program 60 is a ladder diagram program. In Figure 4 it shows, as an example of the commands included in the control program 60, an example of a command for giving input / output instructions for each expansion unit.

[0060] In the control program 60, there are an expansion unit read command and an expansion unit write command. The expansion unit read command is a command for reading data from the expansion unit, and the expansion unit write command is a command for writing data to the expansion unit.

[0061] In Figure 4 it shows the case where four parameters are set for each command in the control program 60. That is, a first parameter, a second parameter, a third parameter, and a fourth parameter are set for the expansion unit read command and the expansion unit write command, respectively.

[0062] The first parameter is the unit number of the expansion unit. That is, by each command, the unit number assigned by the system configuration setting 50 can be set to the first parameter, and thus, it is possible to determine which expansion unit to give input / output instructions to. The second to fourth parameters will be described later.

[0063] For example, in the commands 61 and 62, which are an example of the expansion unit read command in the control program 60, the unit number "U3" assigned to the analog input unit is set. Therefore, the commands 61 and 62 are commands for reading analog values from the analog input unit 14 (the unit with the unit number U3) connected in the third order in the system configuration of the manufacturing device 1. In Figure 4In [the figure], the unit number U3, which is an empty number, is illustrated with shading.

[0064] Figure 5 This is a diagram for explaining the first to fourth parameters of the control program applied to the first and second PLCs related to Embodiment 1. The first parameter of the expansion unit read command is a parameter (number setting parameter) for specifying the unit number of the expansion unit. The second parameter of the expansion unit read command is a parameter for specifying the memory address where the data read from the expansion unit is stored. The third parameter of the expansion unit read command is a parameter for specifying the data register of the main unit 11 where the read data is stored. The fourth parameter of the expansion unit read command is a parameter for specifying the number of read points.

[0065] The first parameter of the expansion unit write command is a parameter for specifying the unit number of the expansion unit. The second parameter of the expansion unit write command is a parameter for specifying the data to be written to the expansion unit. The third parameter of the expansion unit write command is a parameter for specifying the write destination memory address of the expansion unit. The fourth parameter of the expansion unit write command is a parameter for specifying the number of write points.

[0066] Next, the operation processing flow of PLCs 10A and 10B will be described. In addition, the operation processing flows of PLCs 10A and 10B are the same. Therefore, here, the operation processing flow of PLC 10B will be described.

[0067] Figure 6 This is a flowchart showing the operation processing flow of the second PLC related to Embodiment 1. Here, the parsing processing flow of the control program 60 implemented by the PLC 10B as the second PLC will be described. PLC 10B uses, for example, the Figure 3 and Figure 4 system structure setting 50 and control program 60 described above.

[0068] The system structure setting 50 and the control program 60 are written in the main unit 11 of the manufacturing apparatus 2. The main unit 11 parses the control program 60 during the startup processing when the power is turned on.

[0069] First, the main unit 11 reads the number and model of the expansion units connected to itself, and creates the connection structure of the actual machine (actual machine structure). Specifically, the main unit 11 reads the model names of the expansion units connected to the main unit 11 in the order from the closest to the farthest connection position to the main unit 11, and creates the connection structure of the actual machine (step S10). In addition, the main unit 11 calculates the number of expansion units for which the model name has been successfully read.

[0070] Next, the main unit 11 reads out the connection structure (expansion unit connection structure 51) set in the system structure setting 50 included in the control program 60. The main unit 11 compares the connection structure of the created actual machine with the connection structure set in the system structure setting 50. Specifically, for the connection structure of the created actual machine, the main unit 11 determines whether the model types are the same in sequence starting from the expansion unit closer (front) to the main unit 11 in terms of the connection position.

[0071] The main unit 11 determines whether a certain expansion unit among the expansion units included in the system structure setting 50 is set at the current connection position (connection position for comparison) that is the object of determination (step S20).

[0072] When an expansion unit is set at the current connection position that is the object of determination (step S20, Yes), the main unit 11 compares the model type of the expansion unit at the current connection position that is the object of determination with the model type of the actually connected expansion unit. That is, the main unit 11 compares the model type of the expansion unit in the system structure setting 50 at the current connection position with the model type of the expansion unit of the actual machine (step S30). Then, the main unit 11 determines whether the model types of the expansion unit in the system structure setting 50 and the expansion unit of the actual machine are the same (step S40).

[0073] When the model types are not the same (step S40, No), the main unit 11 sets the unit number assigned to the expansion unit at the connection position where the model types are not the same as an empty number in the system structure setting 50 (step S50). That is, as a result of the comparison of the model types between the system structure setting 50 and the actual machine, when there is an expansion unit (model type) that exists in the connection structure of the system structure setting 50 but does not exist in the connection structure of the actual machine, the main unit 11 sets the unit number of this expansion unit as an empty number.

[0074] When there is an empty number, the main unit 11 advances the connection position to be compared (connection position set as the object of determination) by 1 only in the system structure setting 50 (step S60). That is, when there is an empty number, when making the next comparison, the main unit 11 advances only to the next (rear) connection position in the system structure setting 50, and for the actual machine structure, does not advance the connection position to be compared, and compares the model types of the expansion units. Then, the main unit 11 returns to the process of step S20.

[0075] When the model of the expansion unit in the system structure setting 50 is the same as that of the expansion unit of the actual machine (step S40, Yes), the main unit 11 advances the connection position to be compared by 1 for both the system structure setting 50 and the actual machine structure (step S70). Then, the main unit 11 returns to the process of step S20.

[0076] The main unit 11 repeats this comparison process by the number of expansion units in the system structure setting 50. That is, the main unit 11 repeats the processes of steps S20 to S70 by the number of expansion units set in the system structure setting 50.

[0077] Here, a specific example of the model comparison process will be described. Figure 7 This is a diagram for explaining the process of the second PLC according to Embodiment 1 comparing models. Figure 7 In this diagram, the system structure setting 50, the actual machine structure 54, the model comparison result, and the advancing method of the comparison position (connection position) are illustrated.

[0078] The main unit 11 of the PLC 10B, which is the second PLC, compares the model of the system structure setting 50 with the model of the actual machine structure 54. The main unit 11 compares the model of the system structure setting 50 with the model of the actual machine structure 54 for the first expansion unit (the input unit 12 with unit number U1). Here, the model of the expansion unit set in the system structure setting 50 is the input unit 12, and the model of the expansion unit of the actual machine structure 54 is also the input unit 12. Therefore, the model comparison results are the same. In this case, the main unit 11 advances the comparison position of the expansion unit to the next comparison position in both the system structure setting 50 and the actual machine structure 54.

[0079] Next, the main unit 11 compares the model of the system structure setting 50 with the model of the actual machine structure 54 for the second expansion unit (the output unit 13 with unit number U2). Here, the model of the expansion unit set in the system structure setting 50 is the output unit 13, and the model of the expansion unit of the actual machine structure 54 is also the output unit 13. Therefore, the model comparison results are the same. In this case, the main unit 11 advances the comparison position of the expansion unit to the next comparison position in both the system structure setting 50 and the actual machine structure 54.

[0080] Next, the main unit 11 compares the model type set in the system configuration setting 50 with the model type of the actual machine structure 54 for the third expansion unit (the analog input unit 14 with unit number U3). Here, the model type of the expansion unit set in the system configuration setting 50 is the analog input unit 14, and the model type of the expansion unit of the actual machine structure 54 is the communication unit 15. Therefore, the comparison result of the model types is inconsistent. In this case, the main unit 11 sets the unit number U3 of the analog input unit 14 in the system configuration setting 50 to a null number. In addition, since the comparison result of the model types is inconsistent, the main unit 11 advances the comparison position of the expansion unit only to the next comparison position in the system configuration setting 50.

[0081] Next, the main unit 11 compares the model type set in the system configuration setting 50 with the model type of the actual machine structure 54 for the fourth expansion unit (the communication unit 15 with unit number U4). Here, the model type of the expansion unit set in the system configuration setting 50 is the communication unit 15, and the model type of the expansion unit of the actual machine structure 54 is the communication unit 15. Therefore, the comparison result of the model types is consistent. In this case, the main unit 11 advances the comparison position of the expansion unit to the next comparison position in both the system configuration setting 50 and the actual machine structure 54.

[0082] Next, the main unit 11 compares the model type set in the system configuration setting 50 with the model type of the actual machine structure 54 for the fifth expansion unit. Here, no expansion unit is set in both the system configuration setting 50 and the actual machine structure 54. Therefore, the main unit 11 ends the model type comparison process.

[0083] In the process of step S20, when no expansion unit is set at the current connection position that is the determination object of the system configuration setting 50 (step S20, No), the main unit 11 ends the model type comparison process. Then, the main unit 11 extracts the command whose first parameter has a unit number that has become a null number from the control program 60 and invalidates the extracted command (step S80). That is, for each expansion unit included in the control program 60, the main unit 11 extracts the command in which the unit number that has become a null number is set in the first parameter from the command group that gives instructions for input / output, and invalidates all the extracted commands. In this way, by invalidating the commands in which the unit numbers set to null numbers are set, the main unit 11 prevents the expansion units with the unit numbers set to null numbers from operating.

[0084] In this way, the main unit 11 sets the command in which the unit number set to a null number is set in the first parameter to an invalid command. For example, in the case of the control program 60 shown in Figure 4 the main unit 11 sets commands 61 and 62 to invalid commands.

[0085] In addition, in the case of the manufacturing apparatus 1, the connection structure in the system structure setting 50 is the same as the connection structure in the actual machine structure 54. Therefore, the main unit 11 does not perform the setting of null numbers and the invalidation of commands.

[0086] The method of invalidating commands to the unit numbers with null numbers set in the parameters is not limited to the above method and can also be executed by other methods. For example, a determination program for determining whether the corresponding unit number is a null number can be added to the execution condition for driving the command in the ladder diagram program in advance. In this case, if the determination program determines that the unit number is a null number, the main unit 11 can invalidate the command with the unit number with a null number set by setting the execution condition of the command to OFF.

[0087] Through the above analysis process, with respect to the control program 60 running in the PLC 10B of the manufacturing apparatus 2, commands for the analog input unit 14 that does not exist in the actual machine automatically do not operate. Thus, integration of the control program 60 can be achieved in the manufacturing apparatus 1 with the analog input unit 14 and the manufacturing apparatus 2 without the analog input unit 14. That is, the manufacturing apparatuses 1 and 2 can use the common control program 60.

[0088] In addition, in the example of the manufacturing apparatus 2, the case where the analog input unit 14 is not connected to the actual machine is described. However, in the case where any other unit is not connected, the main unit 11 also automatically sets null numbers through the analysis process at startup. Therefore, the manufacturing apparatuses 1 and 2 can use the integrated control program 60. Thus, even when there is a change in the connection structure of the actual machine that is not expected, such as when any unit fails at the manufacturing site, the manufacturing apparatuses 1 and 2 can continue to operate without changing the control program 60.

[0089] Next, the manufacturing apparatus of the comparative example will be described. In the manufacturing apparatus of the comparative example, the unit numbers of the expansion units preset as null numbers are set in the system structure setting 50 of the control program. And when an expansion unit with a unit number set as a null number is actually connected to the actual machine in the manufacturing apparatus of the comparative example, the null number state is released.

[0090] In the case of this manufacturing apparatus of the comparative example, the user has to preset null numbers, which is laborious. In addition, in the case of this manufacturing apparatus of the comparative example, when any expansion unit needs to be removed due to a failure of the expansion unit during the operation of the manufacturing apparatus, etc., changes to the control program are required.

[0091] Thus, in the manufacturing apparatus of the comparative example, when a change outside the assumption of the system configuration setting 50 is required, a change to the control program is necessary. That is, in the manufacturing apparatus of the comparative example, when a change outside the assumption of the system configuration setting 50 is required, it is necessary to create a new control program derived from the control program integrated among multiple manufacturing apparatuses.

[0092] On the other hand, in the manufacturing apparatuses 1 and 2 of Embodiment 1, even when a change outside the assumption of the system configuration setting 50 occurs (such as when an unexpected expansion unit is removed), there is no need to create a new control program, and the original control program 60 can still be used.

[0093] Thus, when the main unit 11 of Embodiment 1 starts up, it compares the connection structure of the expansion units defined in the system configuration setting 50 with the connection structure of the expansion units on the actual machine. And the main unit 11 sets the unit numbers of the expansion units that exist in the system configuration setting 50 but do not exist in the actual machine as null numbers, and invalidates the commands set with the unit numbers set as null numbers. Thereby, even when an unexpected change to the expansion unit occurs in the manufacturing apparatuses 1 and 2, the control program 60 that can be commonly used among multiple different types of manufacturing apparatuses 1 and 2 can be used without modification.

[0094] Embodiment 2

[0095] Next, Figure 8 and Figure 9 are used to describe Embodiment 2. In Embodiment 2, if an expansion unit not set in the system configuration setting 50 is connected to the main unit 11 as an expansion unit of the actual machine, the main unit 11 assigns a new unit number to the connected expansion unit.

[0096] Figure 8 is a diagram showing the structure of a third manufacturing system having a third PLC according to Embodiment 2. The same reference numerals are assigned to the structural elements in Figure 8 that achieve the same functions as the structural elements in Figure 1 of the manufacturing system 101, and repeated descriptions are omitted. The manufacturing system 103 as the third manufacturing system includes an engineering design tool 5, a production status monitoring tool 6, and a manufacturing apparatus 3 as the third manufacturing apparatus.

[0097] The manufacturing apparatus 3 includes sensors 31 and 32, other devices 21, an actuator 41, and a PLC 10C which is a third PLC. The engineering design tool 5 is stored in a computer connected to the PLC 10C. The production status monitoring tool 6 is stored in a computer connected to the PLC 10C. Hereinafter, the computer storing the production status monitoring tool 6 may sometimes be referred to as the production status monitoring computer.

[0098] The computer storing the engineering design tool 5 and the PLC 10C transmit and receive data through USB (Universal Serial Bus) communication. The computer storing the production status monitoring tool 6 and the PLC 10C transmit and receive data through network communication. The network communication here is, for example, Internet (registered trademark) communication.

[0099] The PLC 10C includes a main unit 11, an input unit 12, an output unit 13, an analog input unit 14, a communication unit 15, and a network communication unit 16. That is, the PLC 10C has a network communication unit 16 in addition to the units that the PLC 10A has.

[0100] The network communication unit 16 is also an expansion unit like the input unit 12 and the like. In the second embodiment, a case where the network communication unit 16 is the fifth expansion unit and is connected to the connection position farthest from the main unit 11 will be described.

[0101] The main unit 11 of the PLC 10C has the same functions as the main unit 11 of the PLC 10A and a function of assigning a unit number to a new expansion unit that is actually connected to a machine and not provided in the system configuration setting 50. The main unit 11 of the PLC 10C and the main unit 11 of the PLC 10A may also be main units of different types.

[0102] The production status monitoring computer is a computer that monitors and collects data on the production status of products manufactured by the manufacturing apparatus 3, abnormal contents during processing, and the like. The production status monitoring computer obtains data indicating the production status of products, abnormal contents during processing, and the like from the network communication unit 16.

[0103] The network communication unit 16 is a unit assembled to provide the production status of products manufactured by the manufacturing apparatus 3, abnormal contents during processing, and the like to the production status monitoring computer.

[0104] Next, the operation processing flow of the PLC 10C will be described. Figure 9This is a flowchart showing the operation processing flow of the third PLC related to Embodiment 2. Here, the parsing processing flow of the control program 60 implemented by the PLC 10C as the third PLC will be described. The PLC 10C is used, for example, in Figure 3 and Figure 4 The system structure setting 50 and the control program 60 described. In addition, the system structure setting 50 used by the PLC 10C is the system structure setting 50 in a state where no null numbers are set, and the control program 60 used by the PLC 10C is the control program 60 in a state where no command invalidation processing has been performed.

[0105] The main unit 11 of the manufacturing apparatus 3 parses the control program 60 during the startup processing when the power is turned on. That is, the main unit 11 executes the processing of steps S10 to S80 described in Figure 6 After the main unit 11 has executed the processing of step S80, it determines whether there is an additional expansion unit in the actual machine (step S110). That is, in the processing of step S20, when the main unit 11 determines that no expansion unit is connected at the current connection position to be determined in the system structure setting 50, it determines whether there is an additional expansion unit in the actual machine.

[0106] As a result of the comparison of the models between the system structure setting 50 and the actual machine, in the case where there is an expansion unit (model) that does not exist in the connection structure of the system structure setting 50 but exists in the connection structure of the actual machine, the main unit 11 automatically assigns a new unit number to the expansion unit. That is, when an arbitrary expansion unit of the actual machine is connected to a part corresponding to a connection position further back than the last-stage unit of the connection structure of the system structure setting 50, the main unit 11 assigns a new unit number to the expansion unit.

[0107] In this case, the main unit 11 assigns a new unit number that does not duplicate the unit number assigned to the previous-stage unit. Thus, when there is an additional expansion unit in the actual machine (step S110, Yes), the main unit 11 assigns a unit number that does not duplicate other units to the additional expansion unit (step S120).

[0108] In Embodiment 2, the fifth expansion unit is not set in the system structure setting 50, and the network communication unit 16 of the actual machine is connected to the main unit 11 as the fifth expansion unit. Therefore, the main unit 11 assigns a new unit number (for example, unit number U5) to the network communication unit 16.

[0109] After the main unit 11 is assigned a unit number, it advances the comparison position of the machine types between the system structure setting 50 and the actual machine structure 54 by 1. That is, the main unit 11 advances the connection position to be compared (the connection position set as the determination object) by 1 for both the system structure setting 50 and the actual machine structure 54 (step S130). Then, the main unit 11 returns to the process of step S110.

[0110] The main unit 11 repeats this comparison process and the process of assigning unit numbers by the amount corresponding to the number of newly connected expansion units as the actual machine. That is, the main unit 11 repeats the processes of steps S110 to S130 by the amount corresponding to the number of expansion units added as the actual machine.

[0111] If the main unit 11 determines that there are no additional expansion units remaining in the actual machine (step S110, No), it ends the analysis process of the control program 60. That is, if there are no expansion units with unassigned unit numbers added in the actual machine, the main unit 11 ends the analysis process of the control program 60.

[0112] Thus, the main unit 11 can receive and respond to communication requests from the network communication unit 16 through a system process that operates independently of the control program 60. For example, if a production status monitoring computer sends a communication request for reading the execution status of the control program 60 of the main unit 11 to the network communication unit 16, the network communication unit 16 sends this communication request to the main unit 11. In addition, the network communication unit 16 sends the response sent from the main unit 11 to the production status monitoring computer. Thus, the production status monitoring tool 6 can monitor the execution status of the control program 60.

[0113] In this way, in the manufacturing system 103, for functions such as monitoring that operate through system processes independent of the control program 60, it is possible to operate by assigning unit numbers to additional expansion units, and functions can be added without changing the control program 60.

[0114] Regarding the manufacturing apparatus of the foregoing comparative example, when adding an expansion unit that was not envisaged to be connected at the time of creating the control program in a later stage, for example, a communication unit for monitoring the control state of the main unit by an external computer or the like, it is necessary to change the system structure setting.

[0115] In this way, in the second embodiment, for expansion units that do not exist in the connection structure of the system structure setting 50 but exist in the connection structure of the actual machine, the main unit 11 assigns new unit numbers. Thus, the main unit 11 can add unforeseen expansion units that were not expected to be connected at the time of creating the control program 60 without changing the control program 60.

[0116] Furthermore, by adding the network communication unit 16 of the actual machine as an expansion unit, the production status monitoring tool 6 can perform monitoring and data collection that are not directly related to the control using the control program 60 of the main unit 11 .

[0117] Implementation 3

[0118] Next, use Figures 10 to 12 Embodiment 3 will be described. In Embodiment 3, the engineering tool 5 displays on the display device the extension unit that has become an empty number, the state in which the command is invalidated due to the empty number, and the like.

[0119] Figure 10 FIG. 1 is a diagram showing an example of a first screen displayed on a display device by the engineering design tool according to Embodiment 3. Figure 10 , a system configuration setting monitoring screen 55 which is an example of a first screen displayed on the display device by the engineering tool 5 is shown.

[0120] The system configuration setting monitoring screen 55 is a screen showing Figure 3 The screen shown is a screen showing the contents of the system configuration setting 50. That is, the system configuration setting monitoring screen 55 is a screen for monitoring the vacant number status of the unit number of the expansion unit.

[0121] The method described in Embodiment 1 Figure 3 The connection structure of the system configuration setting 50 shown in the figure has an analog input unit, but Figure 2 In the manufacturing device 2 shown in FIG. 1 , the analog input unit 14 does not exist in the connection structure of the actual machine. Therefore, in the system configuration setting 50, the unit number U3 of the analog input unit is set to an empty number. The engineering design tool 5 reads the empty number status from the main unit 11, as shown in FIG. Figure 10 As shown, it is displayed as the system configuration setting monitoring screen 55.

[0122] The display device that displays the system configuration setting monitoring screen 55 is controlled by the engineering design tool 5. In the system configuration setting monitoring screen 55, the allocation unit number 52 is displayed in a manner that allows the user to know which unit number is set as an empty number. In addition, in the system configuration setting monitoring screen 55, the expansion unit connection structure 51 is displayed in a manner that allows the user to know which expansion unit is in an empty number state. Figure 10 , it is shown that the unit number set as a vacant number is the unit number U3, and the extension unit whose unit number becomes a vacant number state is the analog input unit.

[0123] Figure 11This is a diagram showing an example of a second screen displayed by the engineering design tool according to Embodiment 3 on the display device. In Figure 11 it illustrates an example of the second screen, i.e., the control program monitoring screen 56, displayed by the engineering design tool 5 on the display device.

[0124] The control program monitoring screen 56 represents Figure 4 the execution status of the control program 60 shown. That is, the control program monitoring screen 56 is a screen for monitoring the execution status of the control program 60. In the control program monitoring screen 56, the state where a command is invalidated due to a null unit number is displayed.

[0125] The engineering design tool 5 reads out the state where the command is invalidated from the main unit 11 and, as shown in Figure 11 displays it as the control program monitoring screen 56. The display device for displaying the control program monitoring screen 56 is controlled by the engineering design tool 5.

[0126] In the control program monitoring screen 56, the control program 60 is displayed in a manner that allows the user to know which command is invalidated. In Figure 11 it shows the case where commands 61 and 62 are invalidated.

[0127] In this way, the engineering design tool 5 displays the system structure setting monitoring screen 55 and the control program monitoring screen 56. In a manufacturing site, for example, when maintaining the manufacturing device 2, by displaying the system structure setting monitoring screen 55, the maintainer can confirm which expansion unit among the expansion units included in the control program 60 has a null unit number. Additionally, when maintaining the manufacturing device 2, by displaying the control program monitoring screen 56, the maintainer can confirm which command among the commands included in the control program 60 is invalidated. Thus, the maintainer can efficiently perform maintenance operations.

[0128] In addition, the engineering design tool 5 can also cause the expansion units newly connected as actual machines to be displayed on the display device. Figure 12 This is a diagram showing an example of a third screen displayed by the engineering design tool according to Embodiment 3 on the display device. In Figure 12 it illustrates an example of the third screen, i.e., the system structure setting monitoring screen 57, displayed by the engineering design tool 5 on the display device.

[0129] The system structure setting monitoring screen 57 represents Figure 8 the content of the system structure setting 50 of the manufacturing device 3 shown. That is, the system structure setting monitoring screen 57 is a screen for monitoring the state where new unit numbers are assigned to the expansion units of the newly connected actual machines.

[0130] As described Figure 8 in Figure 8 , when an arbitrary expansion unit of the actual machine is connected to a part corresponding to a connection position further back than the unit at the last stage of the connection structure of the system configuration setting 50, the main unit 11 assigns a new unit number to the expansion unit.

[0131] In Embodiment 3, as an expansion unit of the actual machine, the network communication unit 16 is added as the fifth expansion unit to the manufacturing apparatus 3. In this case, the main unit 11 adds the network communication unit 16 to the last stage of the connection structure of the system configuration setting 50. In addition, the main unit 11 assigns a unit number to the network communication unit 16. In Figure 12 Figure 12 , a case is shown where the main unit 11 has assigned the unit number U5 to the network communication unit 16.

[0132] The main unit 11 transmits the system configuration setting 50 to which a new unit number has been assigned to the engineering design tool 5. As a result, the engineering design tool 5 displays, as the system configuration setting monitoring screen 57, the situation where the main unit 11 is in a state capable of giving an instruction to the expansion unit to which a unit number has been assigned by the addition of the actual machine, on the display device.

[0133] Here, the engineering design tool 5 displays, as the system configuration setting monitoring screen 57, the situation where the main unit 11 is in a state capable of communicating with the network communication unit 16 (a state capable of receiving a communication request and giving a response).

[0134] In the system configuration setting monitoring screen 57, the expansion unit connection structure 51 is displayed in such a manner that it is possible to know which expansion unit is the expansion unit that operates with a unit number automatically assigned. In addition, in the system configuration setting monitoring screen 57, the assigned unit number 52 is displayed in such a manner that it is possible to know the automatically assigned unit number. In Figure 12 Figure 12 , a case is shown where the expansion unit that operates with a unit number automatically assigned is the network communication unit, and the automatically assigned unit number is the unit number U5.

[0135] In this way, according to Embodiment 3, since the engineering design tool 5 displays the system configuration setting monitoring screen 55, the maintainer can confirm which expansion unit of the control program 60 has become an unused number. In addition, since the engineering design tool 5 displays the control program monitoring screen 56, the maintainer can confirm which command of the control program 60 has been invalidated. As a result, the maintainer can efficiently perform maintenance work.

[0136] In addition, the engineering design tool 5 displays the monitoring screen 57 for the system configuration, so that the user can confirm the type of the newly connected expansion unit and the new allocation number assigned to the expansion unit.

[0137] Embodiment 4

[0138] Next, Embodiment 4 will be described. In Embodiment 4, when the connection structure of the system configuration 50 of the control program 60 is inconsistent with the connection structure of the actual machine, the engineering design tool 5 sets a parameter (hereinafter referred to as an error selection parameter) for selecting whether an error is generated by the main unit 11 based on a user instruction.

[0139] The main unit 11 confirms the error selection parameter included in the control program 60 in the analysis process of the control program 60 at startup, and determines whether an error is generated. For example, when it is selected by the error selection parameter not to detect an error, the main unit 11 corrects the structure information of the unit stored inside the PLCs 10A to 10C and performs an operation. That is, when it is selected by the error selection parameter not to detect an error, in the case where the comparison result of the models is inconsistent, the main unit 11 corrects the structure information of the unit stored inside the PLCs 10A to 10C, and performs an operation using the existing actual machine. Thus, as described in Embodiments 1 and 2, the main unit 11 can continue the operation without changing the control program 60 even when an unexpected system configuration change has occurred.

[0140] On the other hand, sometimes it is selected by the error selection parameter to detect an error. In this case, the main unit 11 notifies the user that the connection structure of the control program 60 defined by the creator of the control program 60 in the system configuration 50 is inconsistent with the connection structure of the actual machine as an error. In addition, in order to eliminate this error, the user needs to read out the control program 60 including the system configuration 50 by the engineering design tool 5, and correct the system configuration 50 on the basis of restoring the original control program 60.

[0141] Thus, in Embodiment 4, the main unit 11 has a selection parameter (error selection parameter) that can select a first mode in which an error is generated or a second mode in which no error is generated. Also, when the first mode is selected, the main unit 11 performs normal operation when the connection structure of the expansion units defined in the system configuration setting 50 is the same as the connection structure of the expansion units on the actual machine, and does not perform operation and generates an error when they are different. Further, when the second mode is selected, the main unit 11 performs normal operation when the connection structure of the expansion units defined in the system configuration setting 50 is the same as the connection structure of the expansion units on the actual machine, and also performs operation without detecting an error even when they are different. In addition, in Embodiment 4, it is described that when the first mode is selected and they are different, the main unit 11 does not perform operation and generates an error, but the main unit 11 may also perform operation while notifying of the error when they are different when the first mode is selected. In this case, the user can perform the operation while being aware of the occurrence of the error, or can perform the operation after correcting the system configuration setting 50 to eliminate the error.

[0142] The main unit 11 can notify of an error by lighting a lighting device (not shown) such as a light-emitting diode (LED) mounted on the main unit 11, or can cause the error to be displayed on the display device by the engineering design tool 5. In addition, these error notification methods are an example, and the error may be notified by other methods.

[0143] Thus, according to Embodiment 4, when it is selected by the error selection parameter not to detect an error, the main unit 11 can continue the operation without changing the control program 60 even if the system configuration setting 50 is different from the actual machine structure 54.

[0144] Also, when it is selected by the error selection parameter to detect an error, if the system configuration setting 50 is different from the actual machine structure 54, the engineering design tool 5 or the main unit 11 can notify the user of the error.

[0145] Here, the hardware structure of the main unit 11 will be described. Figure 13This is a diagram showing an example of the hardware structure of the control circuit included in the main unit related to Embodiments 1 to 4. The main unit 11 can be implemented by an input device 300, a processor 100, a memory 200, and an output device 400. Examples of the processor 100 are a CPU (Central Processing Unit, also known as a central processing device, processing device, arithmetic device, microprocessor, microcomputer, DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). Examples of the memory 200 are a RAM (Random Access Memory) and a ROM (Read Only Memory).

[0146] The main unit 11 is implemented by the processor 100 reading and executing a computer-executable processing program 70 for executing the operations of the main unit 11 stored in the memory 200. The processing program 70 for executing the operations of the main unit 11 can also be said to be a program that causes a computer to execute the process or method of the main unit 11.

[0147] The processing program 70 executed by the main unit 11 has a module structure, and each module is loaded onto the main storage device and is generated on the main storage device. The processing program 70 executed by the main unit 11 includes a parsing program that parses the control program 60 during startup processing and the like.

[0148] The input device 300 receives various instructions from the computer storing the engineering design tool 5 and sends them to the processor 100. In addition, the input device 300 receives the system configuration setting 50 and the control program 60 from the computer storing the engineering design tool 5 and sends them to the memory 200. In addition, the input device 300 receives various data from the input unit 12, the analog input unit 14, the communication unit 15, the network communication unit 16, etc. and sends them to the processor 100.

[0149] The memory 200 stores the system configuration setting 50, the control program 60, etc. The system configuration setting 50 and the control program 60 are read out by the processor 100 from the memory 200. In addition, the memory 200 is used as a temporary memory when the processor 100 executes various processes. The output device 400 sends various data to the output unit 13, the communication unit 15, the network communication unit 16, etc.

[0150] At least one of the processing program 70 and the control program 60 may also be provided as a computer program product stored in a computer-readable storage medium in the form of a file that can be installed or executed. In addition, the processing program 70 and the control program 60 may also be provided to the main unit 11 via a network such as the Internet. Furthermore, regarding the functions of the main unit 11, part of them may be implemented by dedicated hardware such as a dedicated circuit, and part of them may be implemented by software or firmware.

[0151] The structure shown in the above embodiments is an example, and it can also be combined with other known technologies, and the embodiments can also be combined with each other. Within the scope not departing from the gist, part of the structure can also be omitted or changed.

[0152] Explanation of reference numerals

[0153] 1 to 3 manufacturing apparatuses, 5 process design tools, 6 production status monitoring tools, 10A to 10C PLCs, 11 main unit, 12 input unit, 13 output unit, 14 analog input unit, 15 communication unit, 16 network communication unit, 21 other devices, 31, 32 sensors, 41 actuators, 50 system structure setting, 51 expansion unit connection structure, 52 allocation unit number, 54 actual machine structure, 55 system structure setting monitoring screen, 56 control program monitoring screen, 57 system structure setting monitoring screen, 60 control program, 61, 62 commands, 70 processing program, 100 processor, 101 to 103 manufacturing systems, 200 memory, 300 input device, 400 output device.

Claims

1. A programmable controller, characterized in that, it has: a main unit that executes a control program for controlling a manufacturing device; and a plurality of expansion units that can be connected to the main unit and are used for function expansion of the manufacturing device, the control program includes a system structure setting for defining a connection structure of the expansion units relative to the main unit and a command for instructing input / output of signals for the expansion units, the system structure setting includes a unit number for identifying a connection position of the expansion units relative to the main unit, the command includes a parameter, i.e., a number setting parameter, for setting the unit number for determining which of the expansion units the signal is input / output to, when starting up, the main unit compares the connection structure of the expansion units defined in the system structure setting with the connection structure of the expansion units on the actual machine, sets the unit numbers of the expansion units that exist in the system structure setting but do not exist in the actual machine as empty numbers, and invalidates the commands set with the unit numbers set as the empty numbers.

2. The programmable controller according to claim 1, characterized in that, when starting up, the main unit sequentially compares the connection structure of the expansion units defined in the system structure setting with the connection structure of the expansion units on the actual machine starting from the expansion unit at the connection position on the front-stage side when observed from the main unit.

3. The programmable controller according to claim 2, characterized in that, the main unit assigns the unit number to the expansion units that are not set in the system structure setting included in the control program but are connected on the actual machine, and then executes the control program.

4. The programmable controller according to claim 1 or 2, characterized in that, the main unit has a selection parameter that can select a first mode or a second mode, when the first mode is selected, if the connection structure of the expansion units defined in the system structure setting is inconsistent with the connection structure of the expansion units on the actual machine, the main unit notifies of an error, when the second mode is selected, even if the connection structure of the expansion units defined in the system structure setting is inconsistent with the connection structure of the expansion units on the actual machine, the main unit does not notify of the error.

5. The programmable controller according to claim 1 or 2, characterized in that, the main unit has a selection parameter that can select a first mode or a second mode, when the first mode is selected, if the connection structure of the expansion units defined in the system structure setting is consistent with the connection structure of the expansion units on the actual machine, the main unit executes the control program, and if it is inconsistent, the main unit does not execute the control program. When the second mode is selected, the main unit executes the control program in both cases where the connection structure of the expansion unit defined in the system structure setting is the same as and different from the connection structure of the expansion unit on the actual machine.

6. A manufacturing system, characterized in that, it has: a programmable logic controller; and a computer that executes an engineering design tool for setting the programmable logic controller, the programmable logic controller has: a main unit that executes a control program for controlling a manufacturing device; and a plurality of expansion units that can be connected to the main unit for expanding the functions of the manufacturing device, the control program includes a system structure setting for defining the connection structure of the expansion unit with respect to the main unit and a command for instructing input / output of signals for the expansion unit, the system structure setting includes a unit number for identifying the connection position of the expansion unit with respect to the main unit, the command includes a parameter, i.e., a number setting parameter, for setting the unit number for determining which expansion unit the signal is input / output to, when starting up, the main unit compares the connection structure of the expansion unit defined in the system structure setting with the connection structure of the expansion unit on the actual machine, sets the unit number of the expansion unit that exists in the system structure setting but does not exist in the actual machine as an empty number, and invalidates the command set with the unit number set as the empty number, the engineering design tool displays the unit number set as the empty number and the command set as invalid on a display device.

7. The manufacturing system according to claim 6, characterized in that, the main unit assigns the unit number to the expansion unit that is not set in the system structure setting but is connected on the actual machine, the engineering design tool displays on the display device the situation where the main unit is in a state capable of instructing the expansion unit assigned with the unit number.

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