Safety control device

Abstract

To provide a safety control device that reduces the user's burden of creating a control program, and can cope with various specifications with different types and combinations of safety input devices.SOLUTION: In a safety control device, a safety control logic is built in advance to safely control a target device, and an arithmetic processing unit executes control on the target device according to the safety control logic. In such a safety control device, a determination processing unit determines types of safety input devices connected to an input unit according to the safety control logic, based on input signals input from the safety input devices to the input unit. Then, the arithmetic processing unit executes control following the safety control logic on the target device depending on the type of the safety input device determined by the determination processing unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a safety control device for safely controlling a target device.

Background Art

[0002] In the field of FA (Factory Automation) technology, while operations such as manufacturing and inspection in the production process are automated by devices such as industrial robots, machine tools, and manufacturing equipment, various risks (such as entry of workers into dangerous areas) may occur along with such automation. Therefore, in the field of FA technology, it is important to avoid risks that may occur with automation, and a safety control device for safely controlling the devices (hereinafter referred to as "target devices") to be automated is essential.

[0003] Specifically, the safety control device is a device that safely controls the target device based on input signals from safety input devices such as an emergency stop switch and a safety light curtain. As an example, when the emergency stop switch is pressed or a person is detected by the safety light curtain, the safety control device immediately stops the target device based on the input signals received from those safety input devices. And such safety control devices include those in which the control of the target device is realized hardware-wise by a circuit including a relay switch or the like, and those in which the control is realized software-wise by causing a processing device such as a CPU to execute a control program. Also, as the latter type of safety control device, a safety PLC (Programmable Logic Controller) that captures and executes a control program created by the user side has been conventionally used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] However, while the aforementioned safety PLC allows users to create their own control programs, enabling safety control tailored to the user's specifications, it also places a significant burden on the user in creating those programs.

[0006] For example, Patent Document 1 proposes a safety control device in which multiple control programs prepared in advance by the supplier are stored within the safety control device, and the user can select and use one of them. With such a safety control device, the user only needs to select a control program, thus reducing the burden on the user of creating control programs. On the other hand, the present inventors have found the following problems with such a safety control device.

[0007] In a control program, even if the basic logic for safely controlling the target equipment (hereinafter referred to as "safety control logic") is the same, if the type of safety input device is different, the processing for determining the operating state of that safety input device will also be different. Therefore, if the type of safety input device (emergency stop switch, safety light curtain, etc.) or its combination is different, a corresponding control program is required. The number of types of safety input devices and their combinations is enormous, and the number of control programs corresponding to them is also enormous. However, there is a limit to the number of control programs that a supplier can provide. Therefore, even if there is a control program available in advance that can be used for the safety control logic according to the user's specifications, if the type of safety input device that the control program can handle is different from the one the user wants to use, the user will not be able to use that control program, and therefore, the safety control device itself will also be unusable. In other words, because there is a limit to the number of control programs that a supplier can provide, the safety control device described in Patent Document 1 is limited in its ability to handle specifications with different types and combinations of safety input devices.

[0008] Therefore, the objective of the present invention is to provide a safety control device that reduces the burden on users, such as creating control programs, and that can accommodate various specifications with different types and combinations of safety input devices. [Means for solving the problem]

[0009] The safety control device according to the present invention is a safety control device that safely controls a target device based on an input signal from a safety input device, and comprises an input unit, an output unit, a safety control logic, and an arithmetic processing unit. A safety input device is connected to the input unit, and a target device is connected to the output unit. The safety control logic is a logic pre-constructed for safely controlling the target device. The arithmetic processing unit executes control on the target device in accordance with the safety control logic. In this configuration, the safety control device further comprises a discrimination processing unit. The discrimination processing unit determines the type of safety input device connected to the input unit in accordance with the safety control logic, based on the input signal input from the safety input device to the input unit. Then, the arithmetic processing unit executes control on the target device in accordance with the safety control logic according to the type of safety input device determined by the discrimination processing unit.

[0010] According to the safety control device described above, the type of safety input device connected to the input section is automatically determined, and control according to the safety control logic is executed on the target device according to the determined type. Therefore, even with the same safety control logic, it becomes possible to accommodate various specifications with different types and combinations of safety input devices.

[0011] The above safety control device may further include a determination processing unit. Here, the determination processing unit determines the operating state of the safety input device connected to the input unit according to the type of safety input device determined by the discrimination processing unit. Then, the calculation processing unit executes control on the target device according to the safety control logic according to the operating state of the safety input device determined by the determination processing unit.

[0012] According to the above configuration, the type of safety input device connected to the input unit is automatically identified, and the operating state of the safety input device is automatically determined according to that type. Based on the determined operating state, control according to the safety control logic is executed on the target device. Therefore, even with the same safety control logic, it becomes possible to accommodate various specifications with different types and combinations of safety input devices.

[0013] Furthermore, the above-mentioned safety control device is equipped with a pre-defined safety control logic, and the type and operating status of the safety input device connected to the input section are automatically identified and determined according to that safety control logic. Therefore, users do not need to create a series of control programs to execute these controls themselves, and thus the burden on users in creating such control programs is reduced.

[0014] The above safety control device may further include determination conditions. Here, the determination conditions are conditions used to compare with the input signal from the safety input device in order to determine the operating state of the safety input device, and differ for each type of safety input device. In such a configuration, the determination processing unit may select a determination condition from among the determination conditions that corresponds to the type of safety input device determined by the discrimination processing unit, and determine the operating state of the safety input device connected to the input unit by comparing that determination condition with the input signal.

[0015] According to the above configuration, the determination conditions corresponding to the type of safety input device identified by the discrimination processing unit are selected, making it possible to accurately determine the operating state of the safety input device according to the type of safety input device.

[0016] The above safety control device may further include a display unit that displays the type of safety input device determined by the determination processing unit, and a confirmation operation unit used to confirm the type displayed on the display unit. In such a configuration, when the type is confirmed by the confirmation operation unit, the determination processing unit may determine the operating state of the safety input device connected to the input unit by selecting and using a determination condition corresponding to that type from among the determination conditions.

[0017] With the above configuration, the user can check the display unit to confirm whether the type of safety input device they intend to use is correctly recognized by the safety control device. Once the display unit confirms that the type of safety input device is correctly recognized by the safety control device, and the correct recognition is confirmed, the operating state of the safety input device is determined. Thus, the operating state of the safety input device is correctly determined based on the correct recognition of the type of safety input device. Consequently, incorrect control of target equipment that may occur due to incorrect connection of safety input devices by the user or incorrect recognition of the type by the safety control device is prevented.

[0018] The above-described safety control device may include multiple safety control logics and further include a logic setting operation unit used to select one of the multiple safety control logics. The input unit may also have multiple terminals for connecting safety input devices, and the terminals to be used for connecting safety input devices to the input unit may be pre-associated with each safety control logic. In such a configuration, when one of the safety control logics is selected by the logic setting operation unit, the discrimination processing unit may use the input signal received at the terminal associated with that safety control logic to determine the type of safety input device connected to that terminal.

[0019] With the above configuration, the options for safety control logic increase, and regardless of which safety control logic is selected, it becomes possible to accommodate various specifications with different types and combinations of safety input devices.

[0020] The safety input device may be a device configured such that an input signal from the safety input device is duplicated into a first input signal and a second input signal. In this case, in the safety control device, the discrimination processing unit may discriminate the type of the safety input device connected to the input unit based on the difference in the conditions satisfied by the first input signal and the second input signal input from the safety input device to the input unit.

[0021] In the above configuration, the fact that the safety input device is duplicated is used for discriminating the type of the safety input device. That is, because the safety input device is duplicated, it is possible to use two signals (the first input signal and the second input signal) for discriminating the type of the safety input device. And, by using two signals in this way, it is possible to increase the number of discriminable types by the number of conditions that the two signals can satisfy.

Effect of the Invention

[0022] According to the present invention, it is possible to reduce the burden on the user such as creating a control program, and to cope with various specifications in which the type of the safety input device and its combination are different.

Brief Description of the Drawings

[0023] [Figure 1] It is a block diagram showing the configuration of the safety control device according to the embodiment. [Figure 2] It is a front view of the safety control device according to the embodiment. [Figure 3] [[ID=二十六]]It is a conceptual diagram showing the configuration of the duplicated safety input device for each type. [Figure 4] It is a conceptual diagram showing the discrimination conditions used in the embodiment. [Figure 5] It is a flowchart showing the safety control process executed in the present embodiment.

Mode for Carrying Out the Invention

[0024] [1] Configuration of the safety control device Figure 1 is a block diagram showing the configuration of a safety control device according to this embodiment. The safety control device of this embodiment is a device that safely controls the target equipment 102 based on an input signal Sp from a safety input device 101. Here, the target equipment 102 is equipment automated by FA technology, such as industrial robots, machine tools, and manufacturing equipment. The safety input device 101 is a device that signals (input signal Sp) to the safety control device when an emergency related to the target equipment 102 occurs (such as a worker entering a hazardous area), such as an emergency stop switch, safety switch NO / NC, or safety light curtain. In this embodiment, both the input signal Sp from the safety input device 101 and the output signal Sq to the target equipment 102 are duplicated so that the target equipment 102 can be safely controlled even if a malfunction (such as failure or poor connection) occurs in the safety input device 101 or the safety control device. Details of the duplication will be described later.

[0025] As shown in Figure 1, the safety control device comprises an input unit 1, an output unit 2, a storage unit 3, an operation unit 4, a display unit 5, and a control unit 6. Figure 2 is a front view of the safety control device, and in this embodiment, the input unit 1, output unit 2, operation unit 4, and display unit 5 are all located on the front of the safety control device. These components are not limited to being located on a single surface; they may also be located on different surfaces. The configuration of each component will be described in detail below.

[0026] [1-1] Input section The input section 1 is the interface to which the safety input device 101 is connected, and the input section 1 is provided with multiple terminals G for connecting the safety input device 101. The input section 1 may also be provided with other terminals for connecting input devices other than the safety input device 101, such as a start switch or monitor.

[0027] In this embodiment, the input unit 1 is configured to allow connection of redundant safety input devices 101. Specifically, the input unit 1 is provided with two drive terminals Gd1 and Gd2, and two receive terminals Gr1 and Gr2 corresponding to these terminals, respectively. These four terminals constitute one group (hereinafter referred to as "terminal group Mg") to which one safety input device 101 is connected. In addition, the input unit 1 is provided with multiple such terminal groups Mg.

[0028] Then, from the two drive terminals Gd1 and Gd2 within each terminal group Mg, the first reference signal St1 and the second reference signal St2, which serve as the basis for judgment (discrimination and judgment) in the discrimination and determination processes described later, are output, respectively. In addition, the first input signal Sp1 and the second input signal Sp2 from the safety input device 101 connected to the terminals are input to the receive terminals Gr1 and Gr2 within each terminal group Mg, respectively. Here, the first input signal Sp1 and the second input signal Sp2 are duplicated versions of the input signal Sp from the safety input device 101. More specifically, it is as follows.

[0029] The redundant safety input devices 101 can be classified into three types as follows. Figures 3(A) to 3(C) are conceptual diagrams showing the configuration of the redundant safety input devices 101 by type. In Figure 3(A), the safety input device 101 is equipped with two normally closed contacts SA1 and SA2 (NC contacts), and their opening and closing operations are configured to be the same operation (including cases where the timing is different) in conjunction with the movement of the operator (button, switch, etc.). Furthermore, when connecting to the input unit 1, both ends of the normally closed contact SA1 are connected to the drive terminal Gd1 and the receive terminal Gr1, and both ends of the normally closed contact SA2 are connected to the drive terminal Gd2 and the receive terminal Gr2.

[0030] When the normally closed contact SA1 is closed, the first reference signal St1 output from the drive terminal Gd1 is directly input to the receive terminal Gr1 as the first input signal Sp1 from the safety input device 101. Therefore, if a constant signal with a voltage level of H (high) level (e.g., 24V) (hereinafter referred to as the "H-level signal") is output from the drive terminal Gd1 as the first reference signal St1, that signal is directly input to the receive terminal Gr1 as the first input signal Sp1. Also, if a constant signal with a voltage level of L (low) level (e.g., 0V) (hereinafter referred to as the "L-level signal") is output from the drive terminal Gd1 as the first reference signal St1, that signal is directly input to the receive terminal Gr1 as the first input signal Sp1. On the other hand, when the normally closed contact SA1 is open, the first reference signal St1 output from the drive terminal Gd1 is blocked by the normally closed contact SA1. Therefore, regardless of whether the first reference signal St1 is a high-level or low-level signal, a low-level signal is input to the receive terminal Gr1 as the first input signal Sp1.

[0031] Similarly, when the normally closed contact SA2 is closed, the second reference signal St2 output from the drive terminal Gd2 is input directly to the receive terminal Gr2 as the second input signal Sp2 from the safety input device 101. Therefore, if an H-level signal is output from the drive terminal Gd2 as the second reference signal St2, that signal is input directly to the receive terminal Gr2 as the second input signal Sp2. Also, if an L-level signal is output from the drive terminal Gd2 as the second reference signal St2, that signal is input directly to the receive terminal Gr2 as the second input signal Sp2. On the other hand, when the normally closed contact SA2 is open, the second reference signal St2 output from the drive terminal Gd2 is blocked by the normally closed contact SA2, so regardless of whether the second reference signal St2 is an H-level or L-level signal, an L-level signal is input to the receive terminal Gr2 as the second input signal Sp2.

[0032] The configuration shown in Figure 3(A) is applied to a safety input device 101 such as an emergency stop switch. Hereinafter, this type of safety input device 101 will be referred to as the "first safety input device 101A". Furthermore, when both normally closed contacts SA1 and SA2 are in the closed state, the operating state of the first safety input device 101A will be considered to be in a "normal state", and when at least one of the normally closed contacts SA1 and SA2 becomes open, the operating state of the first safety input device 101A will be considered to be in an "abnormal state".

[0033] In Figure 3(B), the safety input device 101 is equipped with a normally open contact SB1 (NO contact) and a normally closed contact SB2 (NC contact), and their opening and closing operations are configured to be in opposite directions in conjunction with the movement of an operator (such as an actuator). When connecting to the input unit 1, both ends of the normally open contact SB1 are connected to the drive terminal Gd1 and the receive terminal Gr1, and both ends of the normally closed contact SB2 are connected to the drive terminal Gd2 and the receive terminal Gr2.

[0034] When the normally open contact SB1 is open and the normally closed contact SB2 is closed, the first reference signal St1 output from the drive terminal Gd1 is blocked by the normally open contact SB1. Therefore, regardless of whether the first reference signal St1 is a high-level or low-level signal, a low-level signal is input to the receive terminal Gr1 as the first input signal Sp1. On the other hand, the second reference signal St2 output from the drive terminal Gd2 is input directly to the receive terminal Gr2 as the second input signal Sp2. Thus, if a high-level signal is output from the drive terminal Gd2 as the second reference signal St2, that signal is input directly to the receive terminal Gr2 as the second input signal Sp2. Also, if a low-level signal is output from the drive terminal Gd2 as the second reference signal St2, that signal is input directly to the receive terminal Gr2 as the second input signal Sp2.

[0035] In contrast, if the normally open contact SB1 is closed while the normally closed contact SB2 is open, the first reference signal St1 output from the drive terminal Gd1 is input directly to the receive terminal Gr1 as the first input signal Sp1 from the safety input device 101. Therefore, if an H-level signal is output from the drive terminal Gd1 as the first reference signal St1, that signal is input directly to the receive terminal Gr1 as the first input signal Sp1. Also, if an L-level signal is output from the drive terminal Gd1 as the first reference signal St1, that signal is input directly to the receive terminal Gr1 as the first input signal Sp1. On the other hand, since the second reference signal St2 output from the drive terminal Gd2 is blocked by the normally closed contact SB2, regardless of whether the second reference signal St2 is an H-level or L-level signal, an L-level signal is input to the receive terminal Gr2 as the second input signal Sp2.

[0036] The configuration shown in Figure 3(B) is applied to safety input devices 101 such as safety switches NO / NC. Hereafter, this type of safety input device 101 will be referred to as "second safety input device 101B". Furthermore, the case where the normally open contact SB1 is open and the normally closed contact SB2 is closed will be considered the "normal state" of the operation of the second safety input device 101B, and the case where the normally open contact SB1 is closed and the normally closed contact SB2 is open will be considered the "abnormal state" of the operation of the second safety input device 101B.

[0037] In Figure 3(C), the safety input device 101 is equipped with two sensor elements SC1 and SC2, which output an H-level signal when no detection is performed and an L-level signal when detection is performed. These elements are configured to perform the same operation for the same detected object (such as a person). When connecting to the input unit 1, there are no connections to the drive terminals Gd1 and Gd2. Sensor elements SC1 and SC2 are connected only to the receive terminals Gr1 and Gr2 via output circuits (control circuits that output signals according to the detection results of sensor elements SC1 and SC2; not shown).

[0038] When sensor element SC1 is not detected, an H-level signal is input to the receive terminal Gr1 as the first input signal Sp1 from the safety input device 101. On the other hand, when sensor element SC1 is detected, an L-level signal is input to the receive terminal Gr1 as the first input signal Sp1. Similarly, when sensor element SC2 is not detected, an H-level signal is input to the receive terminal Gr2 as the second input signal Sp2 from the safety input device 101. On the other hand, when sensor element SC2 is detected, an L-level signal is input to the receive terminal Gr2 as the second input signal Sp2.

[0039] The configuration shown in Figure 3(C) is applicable to safety input devices 101 such as safety light curtains. Hereinafter, this type of safety input device 101 will be referred to as the "third safety input device 101C". Furthermore, when both sensor elements SC1 and SC2 are in an undetected state, the operating state of the third safety input device 101C is considered to be in a "normal state", and when at least one of sensor elements SC1 and SC2 is in a detected state, the operating state of the third safety input device 101C is considered to be in an "abnormal state".

[0040] In this case, if the third safety input device 101C is connected to the input unit 1, the output circuit of the third safety input device 101C is controlled to periodically output an off-check pulse (a pulse at an L level) so that it is possible to check whether a signal is being output normally from that device.

[0041] [1-2] Output section Output unit 2 is the interface to which the target device 102 is connected, and output unit 2 is provided with multiple terminals H for connecting the target device 102. In this embodiment, output unit 2 is configured so that the output signal Sq to the target device 102 connected to output unit 2 is duplicated. Specifically, two output terminals H1 and H2 are provided on output unit 2, and these two terminals constitute one group (hereinafter referred to as "terminal group Mh") to which one target device 102 is connected. In addition, output unit 2 is provided with multiple such terminal groups Mh. From the two output terminals H1 and H2 within each terminal group Mh, the same control signal is output to safely control the target device 102 connected to that terminal group Mh.

[0042] [1-3] Storage section The memory unit 3 is a memory such as ROM or RAM, and various information necessary for safety control is stored in the memory unit 3. In this embodiment, the information necessary for safety control, including discrimination conditions, judgment conditions, safety control logic, and default settings, is stored in the memory unit 3. Specifically, it is as follows.

[0043] <Discrimination Criteria> The discrimination criteria are conditions used to compare the input signals Sp (first input signal Sp1 and second input signal Sp2) from the safety input device 101 in order to determine the type of the duplicated safety input device 101 (i.e., whether it is the first safety input device 101A, the second safety input device 101B, or the third safety input device 101C), and are used in the discrimination process described later.

[0044] Figure 4 is a conceptual diagram showing the discrimination conditions used in this embodiment. In this embodiment, the discrimination process is performed when the user has confirmed that the operating state of the safety input device 101 is in a "normal state," and the discrimination conditions are defined so that they can be used in such a discrimination process. Specifically, they are as follows. Depending on the type of safety input device 101, the discrimination process may also be performed when the user has temporarily set the operating state of the safety input device 101 to an "abnormal state," in which case the discrimination conditions will be defined so that they can be used in such a discrimination process.

[0045] In the first safety input device 101A (see Figure 3(A)), when the operating state is "normal," both normally closed contacts SA1 and SA2 are closed, so the first input signal Sp1 and the second input signal Sp2 coincide with the first reference signal St1 and the second reference signal St2, respectively. Therefore, when the same H level signals are output as the first reference signal St1 and the second reference signal St2 (St1=St2=H level), the voltage levels of both the first input signal Sp1 and the second input signal Sp2 will be H level (see Figure 4). Also, when the same L level signals are output as the first reference signal St1 and the second reference signal St2 (St1=St2=L level), the voltage levels of both the first input signal Sp1 and the second input signal Sp2 will be L level (see Figure 4).

[0046] In the second safety input device 101B (see Figure 3(B)), when the operating state is "normal," the normally open contact SB1 is open while the normally closed contact SB2 is closed. As a result, the first input signal Sp1 becomes an L-level signal, and the second input signal Sp2 matches the second reference signal St2. Therefore, when the same H-level signals are output as the first reference signal St1 and the second reference signal St2 (St1=St2=H level), the voltage level of the first input signal Sp1 becomes L level, and the voltage level of the second input signal Sp2 becomes H level (see Figure 4). Also, when the same L-level signals are output as the first reference signal St1 and the second reference signal St2 (St1=St2=L level), the voltage levels of both the first input signal Sp1 and the second input signal Sp2 become L level (see Figure 4).

[0047] In the third safety input device 101C (see Figure 3(C)), when the operating state is "normal," both sensor elements SC1 and SC2 are in an undetected state, so both the first input signal Sp1 and the second input signal Sp2 become H-level signals, excluding the off-check pulse portion. Therefore, regardless of whether the first reference signal St1 and the second reference signal St2 are output as the same H-level signals (St1=St2=H level) or the same L-level signals (St1=St2=L level), the voltage levels of both the first input signal Sp1 and the second input signal Sp2 become H-level, excluding the off-check pulse portion (see Figure 4).

[0048] Thus, the conditions that the first input signal Sp1 and the second input signal Sp2 from the safety input device 101 satisfy when the operating state is "normal" (the combination of expected values ​​of the first input signal Sp1 and the second input signal Sp2 with respect to the first reference signal St1 and the second reference signal St2; specifically, the combination of voltage levels appearing in the first input signal Sp1 and the second input signal Sp2) will differ for each type of safety input device 101. Therefore, in this embodiment, the above conditions that are satisfied when the operating state is "normal" for each type of safety input device 101 are used as discrimination conditions (see Figure 4).

[0049] <Judgment Criteria> The determination conditions are used to compare the input signals Sp (first input signal Sp1 and second input signal Sp2) from the redundant safety input device 101 with the operating state of the device (i.e., whether it is in a normal or abnormal state), and are used in the determination process described later. The determination conditions differ for each type of safety input device 101 (see Figures 3(A) to (C)), and the corresponding conditions are stored in the memory unit 3. Specifically, they are as follows.

[0050] As described above, in the first safety input device 101A, the operating state is considered to be "normal" when both normally closed contacts SA1 and SA2 are in the closed state. Therefore, the operating state of the first safety input device 101A can be determined to be "normal" when the first input signal Sp1 and the second input signal Sp2 match the first reference signal St1 and the second reference signal St2, respectively. Thus, the determination condition for determining the operating state of the first safety input device 101A is that the first input signal Sp1 and the second input signal Sp2 match the first reference signal St1 and the second reference signal St2, respectively. If this condition is met, it is determined to be "normal," and if it is not met, it is determined to be "abnormal."

[0051] In the second safety input device 101B, as described above, the operating state is considered to be "normal" when the normally open contact SB1 is open and the normally closed contact SB2 is closed. Therefore, the operating state of the second safety input device 101B can be determined to be "normal" when the first input signal Sp1 is an L-level signal and the second input signal Sp2 matches the second reference signal St2. Thus, the determination conditions for determining the operating state of the second safety input device 101B are that the first input signal Sp1 is an L-level signal and the second input signal Sp2 matches the second reference signal St2. If these conditions are met, it is determined to be "normal," and if they are not met, it is determined to be "abnormal."

[0052] In the third safety input device 101C, as described above, the operating state is considered to be "normal" when neither sensor element SC1 nor SC2 is detected. Therefore, the operating state of the third safety input device 101C can be determined to be "normal" when the voltage levels of both the first input signal Sp1 and the second input signal Sp2 are at the H level (in this embodiment, when they are at the H level excluding the off-check pulse portion). Thus, the determination condition for determining the operating state of the third safety input device 101C is that the voltage levels of both the first input signal Sp1 and the second input signal Sp2 are at the H level. If this condition is met, it is determined to be "normal," and if it is not met, it is determined to be "abnormal."

[0053] <Safety control logic> The safety control logic is a pre-built logic for safely controlling the target device 102, and it is programmed to control the target device 102 according to the operating state (normal or abnormal) of the safety input device 101. In other words, the safety control logic is the part of the control program executed by the safety control device that is executed after the determination process, and does not include discrimination or determination processes. In this embodiment, multiple such safety control logics are provided to correspond to various specifications, and these are stored in the storage unit 3. Furthermore, for each safety control logic, a terminal group Mg from among the multiple terminal groups Mg provided in the input unit 1 that should be used for connecting the safety input device 101 in that safety control logic is pre-associated.

[0054] <Default settings> The default setting is a pre-configured set of types of safety input devices 101 that can be used with each safety control logic. Specifically, the default setting is a pre-configured set of judgment conditions corresponding to the types of safety input devices 101 that can be used with each safety control logic. More specifically, the default setting is a pre-configured one-to-one association for each safety control logic between information for identifying multiple terminal groups Mg provided in the input unit 1 (such as the numbers of various terminals included in each terminal group Mg) and judgment conditions corresponding to the types of safety input devices 101 that can be connected to those terminal groups Mg.

[0055] [1-4]Operation section The operation unit 4 includes a logic setting operation unit 41, a timer setting operation unit 42, and a confirmation operation unit 43 (see Figure 2). Here, the logic setting operation unit 41 is used to select one of several safety control logics stored in the memory unit 3. In this embodiment, the logic setting operation unit 41 consists of eight setting switches, and the safety control logic is selected according to the on / off sequence of these eight setting switches (moving the knob of the setting switch upwards means on, and moving it downwards means off).

[0056] The timer setting operation unit 42 is used to set the time difference (hereinafter referred to as "off-delay time") from the time the safety input device 101 connected to the input unit 1 is operated (specifically, from the time the operating state of the safety input device 101 is determined in the judgment process) until the output signal Sq to the target device 102 is executed. In this embodiment, the timer setting operation unit 42 is composed of eight setting switches separate from the eight setting switches that make up the logic setting operation unit 41 (see Figure 2), and eight values ​​that have been prepared in advance as configurable off-delay times are associated with each of these eight setting switches. When any one of the eight setting switches is set to ON (ON when the knob of the setting switch is moved up, OFF when it is moved down), the value corresponding to the setting switch that has been set to ON is set as the off-delay time.

[0057] The confirmation operation unit 43 is used to confirm the safety control logic selected in the logic setting operation unit 41, to confirm the off-delay time set in the timer setting operation unit 42, and to confirm the type of safety input device 101 displayed on the display unit 5, which will be described later. In this embodiment, the confirmation operation unit 43 consists of one button (see Figure 2).

[0058] [1-5]Display section The display unit 5 includes a logic status display unit 51, an error status display unit 52, a timer status display unit 53, and an input / output status display unit 54 (see Figure 2). Here, the logic status display unit 51 displays the number of the safety control logic selected in the logic setting operation unit 41. The error status display unit 52 displays abnormalities that have occurred in the safety control device (monitoring abnormalities, wiring abnormalities, circuit abnormalities, power supply abnormalities, etc.) using the error number associated with the abnormality. The timer status display unit 53 displays the off-delay time set in the timer setting operation unit 42. In this embodiment, the timer status display unit 53 is composed of LEDs that correspond one-to-one with the configurable off-delay times, and the illumination of these LEDs indicates which off-delay time has been set. The input / output status display unit 54 displays the type of safety input device 101 determined by the discrimination process described later. In this embodiment, the input / output status display unit 54 is composed of LEDs that correspond one-to-one with all receive terminals Gr1 and Gr2, and the type of safety input device 101 connected to each receive terminal (i.e., whether it is the first safety input device 101A, the second safety input device 101B, or the third safety input device 101C) is indicated by the color of the emitted LEDs (for example, red, yellow, and green). Furthermore, the input / output status display unit 54 has LEDs that correspond one-to-one with all output terminals H1 and H2, and the output status of the safety control device is indicated by the illumination of these LEDs.

[0059] [1-6] Control Unit The control unit 6 is a processing unit such as a CPU. When power is turned on to the safety control device, if any safety control logic has already been selected in the logic setting operation unit 41, or if the state has been changed to a different safety control logic, and that safety control logic has been confirmed by the operation of the confirmation operation unit 43, the control unit 6 will execute the safety control processing for the target device 102 in the "default mode" described below.

[0060] In "default mode," the control unit 6 determines the operating status of all safety input devices 101 connected to the input unit 1 using the determination conditions that are associated by default with the established safety control logic (i.e., the determination conditions associated with the default settings described above) (determination process). Then, while determining the operating status of all safety input devices 101, the control unit 6 executes control on the target device 102 according to the safety control logic described above, in accordance with their operating status (calculation process).

[0061] On the other hand, if no safety control logic is selected in the logic setting operation unit 41 when power is supplied to the safety control device, the control unit 6 executes the safety control processing for the target device 102 in the "changeable mode" described below. In this embodiment, the control unit 6 executes the safety control processing in "changeable mode" when all eight setting switches of the logic setting operation unit 41 are off, and furthermore, all eight setting switches of the timer setting operation unit 42 are off. The control unit 6 may be appropriately modified to execute the safety control processing in "changeable mode" when all eight setting switches of the logic setting operation unit 41 are off, regardless of the state of the eight setting switches of the timer setting operation unit 42.

[0062] In "changeable mode," the control unit 6 accepts the selection of safety control logic in the logic setting operation unit 41, the setting of the off-delay time in the timer setting operation unit 42, and confirmation by operation of the confirmation operation unit 43, and also makes it possible to change the type of safety input device 101 from the one that is by default associated with the accepted safety control logic. The control unit 6 then determines the type of safety input device 101 connected to the input unit 1, including all those that have been changed and those that remain at the default (determination process). Subsequently, the control unit 6 determines the operating state of all safety input devices 101 connected to the input unit 1 using the determination conditions corresponding to the type of safety input device 101 (determination process). Then, while determining the operating state of all safety input devices 101, the control unit 6 executes control on the target device 102 according to the safety control logic described above, according to their operating states (calculation process).

[0063] In this embodiment, the discrimination process, determination process, and calculation process described above are executed by the discrimination processing unit 61, determination processing unit 62, and calculation processing unit 63, respectively, which are configured within the control unit 6 (see Figure 1). Specifically, these processing units are configured in software by causing the processing unit (CPU, etc.), which is the control unit 6, to execute a main program, and such a main program is stored in the storage unit 3. Alternatively, the above processing units may be configured in hardware by constructing the control unit 6 as a circuit within the safety control device.

[0064] The following describes in detail the safety control processes (including discrimination, determination, and calculation processes) performed by the safety control device.

[0065] [2] Safety control processes performed by the safety control device Figure 5 is a flowchart showing the safety control process performed in this embodiment. This safety control process starts when power is supplied to the safety control device.

[0066] When safety control processing is initiated, the control unit 6 of the safety control device determines whether the safety control logic was already selected by the logic setting operation unit 41 when power was turned on to the safety control device, in order to determine whether the safety control processing should be executed in default mode or changeable mode (step S100).

[0067] Specifically, if at least one of the eight setting switches of the logic setting operation unit 41 is set to ON (the knob of the setting switch is moved upward), then the safety control logic corresponding to the ON / OFF arrangement of the eight setting switches at that time is selected by the logic setting operation unit 41, and the control unit 6 can determine in step S100 that it is "selected (Yes)".

[0068] On the other hand, if all eight setting switches of the logic setting operation unit 41 are set to OFF (the knobs of the setting switches are moved downwards), then no safety control logic is selected in the logic setting operation unit 41, and the control unit 6 can determine in step S100 that it is "not selected (No)". In this embodiment, the control unit 6 determines in step S100 that it is "not selected (No)" if, in addition to all eight setting switches of the logic setting operation unit 41 being OFF, all eight setting switches of the timer setting operation unit 42 are also OFF. The control unit 6 may be modified to determine in step S100 that it is "not selected (No)" if all eight setting switches of the logic setting operation unit 41 are OFF, regardless of the state of the eight setting switches of the timer setting operation unit 42.

[0069] Then, if the control unit 6 determines in step S100 that it is "selected (Yes)", it decides that the safety control process should be executed in "default mode" and executes the process from step S101. On the other hand, if it determines in step S100 that it is "not selected (No)", it decides that the safety control process should be executed in "changeable mode" and executes the process from step S111. Specifically, it is as follows.

[0070] <Default Mode> In default mode, the control unit 6 first determines whether the safety control logic selected in the logic setting operation unit 41 has been confirmed by the operation of the confirmation operation unit 43 (step S101). In this embodiment, the control unit 6 determines whether the safety control logic selected in the logic setting operation unit 41 and the off-delay time set in the timer setting operation unit 42 have been confirmed simultaneously by the operation of the confirmation operation unit 43.

[0071] The control unit 6 then repeatedly executes step S101 until it determines that "confirmed (Yes)" in step S101. At this time, the user can check whether the desired safety control logic has been correctly selected by checking the number displayed on the logic status display unit 51. The user can also check whether the desired off-delay time has been correctly set by checking which LEDs are lit on the timer status display unit 53. Furthermore, the user may change the safety control logic selected in the logic setting operation unit 41 to a different safety control logic before confirming, or change the off-delay time set in the timer setting operation unit 42 to a different off-delay time before confirming.

[0072] If the control unit 6 determines in step S101 that the decision has been "confirmed (Yes)", it reads the default conditions associated with the confirmed safety control logic from the storage unit 3 by referring to the default settings stored in the storage unit 3 (step S102). Specifically, the control unit 6 reads the conditions associated with each terminal group Mg, along with information for identifying the terminal group Mg. This makes it possible for the control unit 6 to determine the operating state of the safety input device 101 connected to each terminal group Mg using the conditions corresponding to the terminal group Mg.

[0073] Next, the control unit 6 starts outputting the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in each terminal group Mg in order to start determining the operating status of the safety input device 101 (step S103). Specifically, in relation to the determination condition for determining the operating status of the first safety input device 101A or the second safety input device 101B among the determination conditions read in step S102, the control unit 6 starts outputting the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in the terminal group Mg corresponding to the determination condition. On the other hand, the third safety input device 101C outputs signals corresponding to its own operating state as the first input signal Sp1 and the second input signal Sp2, regardless of the presence or absence of the first reference signal St1 and the second reference signal St2. Therefore, in relation to the determination condition for determining the operating state of the third safety input device 101C among the determination conditions read in step S102, the control unit 6 may or may not output the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in the terminal group Mg corresponding to the determination condition.

[0074] In this way, the first input signal Sp1 and the second input signal Sp2 from the safety input device 101 connected to each terminal group Mg are input to the receive terminals Gr1 and Gr2 within each terminal group Mg.

[0075] Then, the control unit 6 uses the determination conditions read in step S102 to compare the first input signal Sp1 and the second input signal Sp2 input to the receive terminals Gr1 and Gr2 within each terminal group Mg with the determination conditions corresponding to that terminal group Mg, thereby determining the operating state (whether it is in a normal state or an abnormal state) of the safety input device 101 connected to that terminal group Mg (step S104). In this way, the control unit 6 determines the operating state of all safety input devices 101 connected to the input unit 1.

[0076] Subsequently, the control unit 6 executes control on the target device 102 according to the safety control logic, based on the operating state of the safety input device 101 determined in step S104 (step S105). Specifically, if the control unit 6 determines that at least one of the operating states of the safety input device 101 is in an "abnormal state," and it becomes necessary to stop the target device 102 according to the safety control logic, it outputs a duplicated signal for emergency stopping of the target device 102 as an output signal Sq from the output unit 2 (output terminals H1 and H2). At this time, the control unit 6 outputs the output signal Sq from the output unit 2 at a timing that takes into account the off-delay time set in the timer setting operation unit 42. For example, if the off-delay time is set to 0 seconds, the control unit 6 outputs the output signal Sq from the output unit 2 immediately after determining an "abnormal state" in step S104. As another example, if the off-delay time is set to 1 second, the control unit 6 outputs the output signal Sq from the output unit 2 1 second after determining that an "abnormal state" is occurring in step S104.

[0077] Then, the control unit 6 safely controls the target device 102 by repeatedly executing the process from step S104 until it determines in step S106 that the power supply to the safety control device has been "cut off (Yes)".

[0078] With safety control processing in this default mode, the types of safety input devices 101 that can be connected to each terminal group Mg are limited to those set by default. However, the user can simply select the safety control logic they want to use and execute control on the target device 102 according to that safety control logic. On the other hand, some users may want to use a different type of safety input device 101 than the default, even if the safety control logic is the same. Therefore, the safety control device of this embodiment is designed to allow the user to change the type of safety input device 101 by executing safety control processing in the changeable mode described below.

[0079] <Changeable Mode> In changeable mode, the user can select a safety control logic using the logic setting operation unit 41, and change the type of safety input device 101 used by the selected safety control logic from the one that is assigned to the safety control logic by default, according to their own specifications. Specifically, this is as follows:

[0080] First, the control unit 6 determines whether a safety control logic has been selected using the logic setting operation unit 41 and whether the selected safety control logic has been confirmed by the operation of the confirmation operation unit 43 (step S111). At this time, the user can confirm whether the desired safety control logic has been correctly selected by checking the number displayed on the logic status display unit 51. In this embodiment, the user can also confirm whether the desired off-delay time has been correctly set by setting the off-delay time using the timer setting operation unit 42 and checking which LED is lit on the timer status display unit 53. Therefore, in this embodiment, in step S111, the control unit 6 determines whether the safety control logic selected in the logic setting operation unit 41 and the off-delay time set in the timer setting operation unit 42 have been simultaneously confirmed by the operation of the confirmation operation unit 43. The control unit 6 then repeatedly executes step S111 until it can determine that "confirmed (Yes)" in step S111.

[0081] If the control unit 6 determines in step S111 that the result is "confirmed (Yes)", it determines the type of safety input device 101 connected to the input unit 1 according to the confirmed safety control logic (step S112). In other words, the control unit 6 determines the type of safety input device 101 connected to the input unit 1 by the user according to their own specifications.

[0082] Specifically, the control unit 6 temporarily outputs a first reference signal St1 and a second reference signal St2 from the drive terminals Gd1 and Gd2 within each terminal group Mg, respectively, in order to determine the type of safety input device 101. In this embodiment, the control unit 6 outputs a pulse signal as the first reference signal St1, in which the voltage changes periodically (for example, every 10 milliseconds) between a high level (for example, 24V) and a low level (for example, 0V), and outputs the same pulse signal as the first reference signal St1 as the second reference signal St2. The first reference signal St1 and the second reference signal St2 output for type determination may be the same as or different from the first reference signal St1 and the second reference signal St2 output for determining the operating state in step S103.

[0083] As a result, the receive terminals Gr1 and Gr2 within each terminal group Mg receive signals corresponding to the type of safety input device 101, as the first input signal Sp1 and the second input signal Sp2 from the safety input device 101 connected to the terminal group Mg. Specifically, this is as follows (see Figure 4).

[0084] When the first safety input device 101A is connected, the pulse signals, which are the first reference signal St1 and the second reference signal St2, are input directly to the receive terminals Gr1 and Gr2 as the first input signal Sp1 and the second input signal Sp2, respectively. Therefore, the voltage levels (Sp1,Sp2) of the first input signal Sp1 and the second input signal Sp2 appear in combinations such that (Sp1,Sp2)=(H,H) for the H-level portion of the pulse signal and (Sp1,Sp2)=(L,L) for the L-level portion of the pulse signal.

[0085] When the second safety input device 101B is connected, a low-level signal is always input to the receive terminal Gr1 as the first input signal Sp1 with respect to the pulse signal which is the first reference signal St1, and the pulse signal which is the second reference signal St2 is input directly to the receive terminal Gr2 as the second input signal Sp2. Therefore, the voltage levels (Sp1,Sp2) of the first input signal Sp1 and the second input signal Sp2 appear in combinations such that (Sp1,Sp2)=(L,H) for the high-level portion of the pulse signal and (Sp1,Sp2)=(L,L) for the low-level portion of the pulse signal.

[0086] When the third safety input device 101C is connected, regardless of the pulse signals which are the first reference signal St1 and the second reference signal St2, H-level signals are input to the receive terminals Gr1 and Gr2 as the first input signal Sp1 and the second input signal Sp2, respectively. Therefore, the voltage levels (Sp1,Sp2) of the first input signal Sp1 and the second input signal Sp2 will appear in combinations such that (Sp1,Sp2)=(H,H) for both the H-level and L-level portions of the pulse signal.

[0087] If a safety input device 101 of a different type is connected, or if any of the above safety input devices 101 is connected but is malfunctioning (e.g., poor contact), not powered on, or in an "abnormal state," the voltage levels of the first input signal Sp1 and the second input signal Sp2 (Sp1, Sp2) will appear in combinations other than those described above.

[0088] Therefore, the control unit 6 uses the discrimination conditions stored in the memory unit 3 (see Figure 4) to determine which of the three types of discrimination conditions the combination of voltage levels appearing in the first input signal Sp1 and the second input signal Sp2 input to the receive terminals Gr1 and Gr2 in each terminal group Mg matches, thereby determining the type of safety input device 101 connected to that terminal group Mg. At this time, if the control unit 6 determines that none of the discrimination conditions corresponding to the three types match, it determines that the type of safety input device 101 is not one of the three types, or that one of the three types is connected but is malfunctioning (e.g., poor contact), not powered on, or in an "abnormal state".

[0089] When the third safety input device 101C is connected to the input unit 1, as described above, the first input signal Sp1 and the second input signal Sp2 will periodically include off-check pulses. Therefore, depending on the timing of determining the type of safety input device 101, the off-check pulse may be used for determination. However, although the off-check pulse is a signal from the third safety input device 101C, it does not match the determination conditions corresponding to the third safety input device 101C. As a result, depending on the timing of determining the type, it may become impossible to accurately determine the type.

[0090] Therefore, in this embodiment, in order to accurately determine the type of safety input device 101, the control unit 6 considers the portion in the pulse signals, which are the first reference signal St1 and the second reference signal St2, where a high level and a low level appear consecutively once each, as one period, and compares the voltage levels for a predetermined number of periods (for example, 100 periods) with the discrimination criteria. Then, if the control unit 6 finds a discrimination criterion that matches a predetermined percentage (for example, 90%) or more as a result of the comparison, it determines the type of safety input device 101 based on that discrimination criterion.

[0091] In this embodiment, the duplication of the safety input device 101 is utilized to determine the type of safety input device 101. That is, because the safety input device 101 is duplicated, it is possible to use two signals (first input signal Sp1 and second input signal Sp2) to determine the type of safety input device 101. By using two signals in this way, the number of types that can be determined can be increased by the number of conditions that the two signals can satisfy (in this embodiment, the number of combinations of voltage levels). In this embodiment, it is possible to determine three types of safety input devices 101 (i.e., the first safety input device 101A, the second safety input device 101B, and the third safety input device 101C).

[0092] Then, the control unit 6 displays the type of safety input device 101 determined in step S112 on the input / output status display unit 54 (step S113). Specifically, the control unit 6 illuminates the LEDs corresponding to the receive terminals Gr1 and Gr2 in each terminal group Mg in a color corresponding to the type of safety input device 101 connected to the terminal group Mg (the type determined in step S112). On the other hand, if the control unit 6 determines in step S112 that the combination of voltage levels appearing in the first input signal Sp1 and the second input signal Sp2 does not match any of the discrimination conditions corresponding to the three types (i.e., it appeared in a combination other than those that appear in the three types), then in step S113, it may display an error number indicating this on the error status display unit 52. Alternatively, the control unit 6 may indicate an error by another means (for example, by sequentially changing the color of the corresponding LED on the input / output status display unit 54) instead of displaying an error number.

[0093] This allows the user to check whether the type of safety input device 101 they intend to use is correctly recognized by the safety control device by checking the LED's illumination color and error number. If the user confirms that the type of safety input device 101 is correctly recognized, they can confirm the type of safety input device 101 displayed on the input / output status display unit 54 by operating the confirmation operation unit 43. On the other hand, if the user confirms that the safety input device 101 is not correctly recognized, they can correct errors in the type or connection of the safety input device 101 until the LED's illumination color indicates that it is correctly recognized. In this case, correcting the error may require restarting the safety control device.

[0094] Therefore, the control unit 6 determines whether the type of safety input device 101 identified in step S112 has been confirmed (step S114), and repeats the process from step S112 until it can determine that it has been confirmed (Yes). Then, if the control unit 6 determines in step S114 that it has been confirmed (Yes), it proceeds to the next step S115.

[0095] In step S115, the control unit 6 selects a determination condition from the determination conditions stored in the memory unit 3 that corresponds to the type of safety input device 101 determined in step S112, and reads that determination condition from the memory unit 3. Specifically, for each terminal group Mg, the control unit 6 selects a determination condition that corresponds to the type of safety input device 101 connected to that terminal group Mg (the type determined in step S112), and reads that determination condition from the memory unit 3. This makes it possible for the control unit 6 to determine the operating state of the safety input device 101 connected to each terminal group Mg using the determination condition that corresponds to the type of safety input device 101.

[0096] Next, the control unit 6 moves to step S103 to begin determining the operating state of the safety input device 101, and starts outputting the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in each terminal group Mg. Specifically, in relation to the determination condition for determining the operating state of the first safety input device 101A or the second safety input device 101B among the determination conditions read in step S115, the control unit 6 starts outputting the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in the terminal group Mg corresponding to that determination condition. On the other hand, the third safety input device 101C outputs signals corresponding to its own operating state as the first input signal Sp1 and the second input signal Sp2, regardless of the presence or absence of the first reference signal St1 and the second reference signal St2. Therefore, in relation to the determination condition for determining the operating state of the third safety input device 101C among the determination conditions read in step S102, the control unit 6 may or may not output the first reference signal St1 and the second reference signal St2 from the drive terminals Gd1 and Gd2 in the terminal group Mg corresponding to the determination condition.

[0097] In this way, the first input signal Sp1 and the second input signal Sp2 from the safety input device 101 connected to each terminal group Mg are input to the receive terminals Gr1 and Gr2 within each terminal group Mg.

[0098] Then, the control unit 6 moves to step S104 and, using the determination conditions read in step S115, compares the first input signal Sp1 and the second input signal Sp2 input to the receive terminals Gr1 and Gr2 within each terminal group Mg with the determination conditions corresponding to that terminal group Mg to determine the operating state (whether it is in a normal state or an abnormal state) of the safety input device 101 connected to that terminal group Mg. In this way, the control unit 6 determines the operating state of all safety input devices 101 connected to the input unit 1.

[0099] According to this determination process, a determination condition corresponding to the type of safety input device 101 determined in step S112 (determination process) is selected, so that the operating state of the safety input device 101 can be accurately determined according to the type of safety input device 101. In addition, in this embodiment, the input / output status display unit 54 confirms that the type of safety input device 101 is correctly recognized by the safety control device, and the determination process is executed when the correctly recognized type is confirmed, so that the operating state of the safety input device 101 is correctly determined based on the correct recognition of the type of safety input device 101. Accordingly, incorrect control of the target device 102 that may occur due to incorrect connection of the safety input device 101 by the user or incorrect recognition of the type by the safety control device is prevented.

[0100] Subsequently, the control unit 6, as in the default mode, executes control on the target device 102 according to the safety control logic described above, based on the operating state of the safety input device 101 determined in step S104 (step S105). Then, the control unit 6 safely controls the target device 102 by repeatedly executing the process from step S104 until it can determine in step S106 that the power supply to the safety control device has been "cut off (Yes)".

[0101] With this modifiable mode of safety control processing, the type of safety input device 101 connected to the input unit 1 is automatically determined, and the operating state of the safety input device 101 is automatically determined according to that type. Based on the determined operating state, control according to the safety control logic is executed on the target device 102. Therefore, even with the same safety control logic, it becomes possible to accommodate various specifications with different types and combinations of safety input devices 101.

[0102] Furthermore, the safety control device of this embodiment is pre-equipped with multiple selectable safety control logics, and the type and operating state of the safety input device 101 connected to the input unit 1 are automatically determined according to the selected safety control logic. Therefore, the user does not need to create a series of control programs to execute these controls, and thus the burden on the user of creating such control programs is reduced. Moreover, the number of safety control logic options increases, and regardless of which safety control logic is selected, it can accommodate various specifications with different types and combinations of safety input devices 101.

[0103] [3] Variant [3-1] First variation In the safety control device described above, the discrimination process may be appropriately modified to determine the type of safety input device 101 based on the input signal Sp input from the safety input device 101 to the input unit 1, and is not limited to determining the type using the discrimination conditions described above (i.e., determining based on the difference in the conditions satisfied by the first input signal Sp1 and the second input signal Sp2).

[0104] Alternatively, in the discrimination process, a first reference signal St1 and a second reference signal St2 may be output from drive terminals Gd1 and Gd2 by applying voltage to those terminals, and a first input signal Sp1 and a second input signal Sp2 may be obtained by measuring the voltages at receive terminals Gr1 and Gr2. Then, the type may be determined using the voltages measured at receive terminals Gr1 and Gr2.

[0105] Furthermore, in the discrimination process, a first reference signal St1 and a second reference signal St2 may be output from the drive terminals Gd1 and Gd2 by applying current to them, and a first input signal Sp1 and a second input signal Sp2 may be obtained by measuring the voltages at the receive terminals Gr1 and Gr2. Then, the resistance value between the drive terminals and the receive terminals may be determined using the current applied to the drive terminals Gd1 and Gd2 and the voltages measured at the receive terminals Gr1 and Gr2, and the type may be determined based on this resistance value.

[0106] [3-2] Second variation The safety control process performed by the safety control device described above (see Figure 5) may be appropriately modified to proceed to step S101 and execute processing in default mode if the setting switch is changed on / off in the logic setting operation unit 41 or timer setting operation unit 42 during the execution of the safety control process.

[0107] [3-3] Third variation In the safety control device described above, the determination process may be appropriately modified to determine the operating state of the safety input device 101 connected to the input unit 1 in a manner that can be determined according to the type of safety input device 101 determined by the determination process, and is not limited to determining the operating state using the determination conditions described above (i.e., determining the operating state by comparing the first input signal Sp1 and the second input signal Sp2 with the determination conditions).

[0108] [3-4] Fourth variation The safety control device described above may be modified as appropriate to one that does not incorporate a default mode into its safety control processing (i.e., one that executes safety control processing only in a modifiable mode).

[0109] [3-5] Fifth variation Even if the safety input device 101 is not redundant, if the type of safety input device 101 can be determined based on the input signal Sp from the safety input device 101, the safety control processing in the changeable mode described above can also be applied to a safety control device that is capable of connecting such a non-redundant safety input device 101.

[0110] Furthermore, the safety control device described above may be modified as appropriate to one in which the output signal Sq from the output unit 2 to the target device 102 is not duplicated.

[0111] [3-6] Sixth variation The safety control device described above may be modified as appropriate to have duplicated various processing units (discrimination processing unit 61, determination processing unit 62, and calculation processing unit 63) so that the target device 102 can be safely controlled.

[0112] The above description of embodiments should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not by the embodiments described above. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the claims.

[0113] Furthermore, the subject matter of the invention is not limited to a safety control device; elements constituting it (such as the control unit 6), control methods, programs, etc., may be extracted individually, or parts of them may be extracted partially. [Explanation of Symbols]

[0114] 1 Input section 2 Output section 3 Storage section 4 Control section 5 Display section 6 Control Unit G, H terminal 41 Logic setting operation unit 42 Timer setting operation unit 43 Confirmation operation section 51 Logic Status Display Unit 52 Error status display section 53 Timer status display unit 54 Input / Output Status Display Unit 61 Discrimination Processing Unit 62. Determination Processing Unit 63. Arithmetic Processing Unit H1, H2 output terminals Mg, Mh terminal group SP Input Signal Sq output signal 101 Safety Input Devices 101A First Safety Input Device 101B Second Safety Input Device 101C Third Safety Input Device 102 Target devices Gd1, Gd2 drive terminals Gr1, Gr2 Receiver Terminals SA1, SA2 Normally closed contact SB1 Normally open contact SB2 Normally closed contact SC1, SC2 sensor elements Sp1 First Input Signal Sp2 Second Input Signal St1 First Reference Signal St2 2nd reference signal

Claims

1. A safety control device that safely controls a target device based on an input signal from a safety input device, The input section to which the safety input device is connected, The output unit to which the aforementioned target device is connected, A safety control logic pre-built to safely control the aforementioned target equipment, A discrimination processing unit for determining the type of safety input device connected to the input unit, A calculation processing unit executes control on the target device according to the safety control logic, based on the type of safety input device determined by the discrimination processing unit, Equipped with, The safety input device is configured such that the input signal from the safety input device is duplicated into a first input signal Sp1 and a second input signal Sp2. The input unit includes a first drive terminal and a second drive terminal for outputting a first reference signal St1 and a second reference signal St2, respectively, to the safety input device connected to the input unit, and a first receive terminal and a second receive terminal for receiving two signals output from the safety input device corresponding to those reference signals as the first input signal Sp1 and the second input signal Sp2, respectively. The discrimination processing unit is capable of outputting two signals of the same level from the first drive terminal and the second drive terminal as the first reference signal St1 and the second reference signal St2 to the safety input device connected to the input unit, and when these two signals are output while changing their levels, the safety control device determines the type of safety input device based on the difference in conditions satisfied by the first reference signal St1 and the second reference signal St2 and the first input signal Sp1 and the second input signal Sp2 that are input to the first receive terminal and the second receive terminal, respectively.

2. A determination processing unit determines the operating state of the safety input device connected to the input unit according to the type of safety input device determined by the determination processing unit. Furthermore, The safety control device according to claim 1, wherein the calculation processing unit executes control on the target device in accordance with the safety control logic according to the operating state of the safety input device determined by the determination processing unit.

3. The conditions used to determine the operating state of the safety input device are those used to compare the first input signal Sp1 and the second input signal Sp2 from the safety input device, and further comprising different determination conditions for each type of safety input device. The safety control device according to claim 2, wherein the determination processing unit selects a determination condition from among the determination conditions that corresponds to the type of safety input device determined by the determination processing unit, and determines the operating state of the safety input device connected to the input unit by comparing the determination condition with the first input signal Sp1 and the second input signal Sp2.

4. A display unit that displays the type of safety input device determined by the discrimination processing unit, A confirmation operation unit used to confirm the type displayed on the display unit, Furthermore, The safety control device according to claim 3, wherein the determination processing unit determines the operating state of the safety input device connected to the input unit by selecting and using the determination condition corresponding to the type from among the determination conditions when the type is determined by the determination operation unit.

5. The system comprises multiple safety control logics, and further comprises a logic setting operation unit used to select one of the multiple safety control logics. The input section is provided with multiple terminal groups, each consisting of a first drive terminal, a second drive terminal, a first receive terminal, and a second receive terminal, which are terminals for connecting the safety input device. The terminal groups to be used for connecting the safety input device to the input section are pre-associated with each safety control logic. The safety control device according to any one of claims 1 to 4, wherein the discrimination processing unit, when any safety control logic is selected by the logic setting operation unit, determines the type of safety input device connected to the terminal group using the first input signal Sp1 and the second input signal Sp2 that are input to the first receive terminal and the second receive terminal of the terminal group associated with that safety control logic.

6. When the first reference signal St1 and the second reference signal St2 are output while keeping their levels the same, changing between L level and H level (> L level), the above conditions apply: Condition (1) states that if both the first reference signal St1 and the second reference signal St2 are H level signals, then both the first input signal Sp1 and the second input signal Sp2 will be H level signals, and if both the first reference signal St1 and the second reference signal St2 are L level signals, then both the first input signal Sp1 and the second input signal Sp2 will be L level signals. Condition (2) states that if both the first reference signal St1 and the second reference signal St2 are H level signals, then the first input signal Sp1 becomes an L level signal while the second input signal Sp2 becomes an H level signal, and if both the first reference signal St1 and the second reference signal St2 are L level signals, then both the first input signal Sp1 and the second input signal Sp2 become L level signals. Condition (3) states that if both the first reference signal St1 and the second reference signal St2 are H level signals, then both the first input signal Sp1 and the second input signal Sp2 are H level signals, and if both the first reference signal St1 and the second reference signal St2 are L level signals, then both the first input signal Sp1 and the second input signal Sp2 are H level signals. It includes, The aforementioned discrimination processing unit If the above condition (1) is met, the type of safety input device is determined to be a first safety input device having two normally closed contacts, configured such that their opening and closing operations are linked to the movement of the operator and result in the same operation. If the above condition (2) is met, the type of safety input device is determined to be a second safety input device equipped with a normally open contact and a normally closed contact, and configured such that their opening and closing operations are in opposite directions in conjunction with the movement of the operator. The safety control device according to any one of claims 1 to 5, wherein if the above condition (3) is met, the type of safety input device is determined to be a third safety input device comprising two sensor elements, wherein their detection operations are configured to be the same for the object to be detected.

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