Functional Unit

Abstract

To suppress rush current in activating a control system having a plurality of function units.SOLUTION: A control system (1A) includes a plurality of function units (101, 201A to 201D), and a power supply line (11). The plurality of function units (101, 201A to 201D) include power supply circuits (14A, 24A to 24D) for generating an internal power supply voltage from a power supply voltage supplied to the power supply line (11), capacitors (15A, 25A to 25D) connected to inputs of the power supply circuits (14A, 24A to 24D), and starting circuits (17A, 27A to 27D) configured so as to sequentially supply a power supply voltage with a time difference to the power supply circuits (14A, 24A to 24D) of the plurality of function units (101, 201A to 201D) in supplying power to the control system (1A), respectively.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device and a functional unit that constitutes the control device. [Background technology]

[0002] When powering up an electrical device, a current that greatly exceeds the steady-state current may temporarily flow. This type of current is generally called an inrush current.

[0003] Various circuits for suppressing inrush current have been proposed. For example, Japanese Patent Application Laid-Open No. 2018-148511 (Patent Document 1) proposes an inrush current suppression circuit that makes it possible to achieve the effect of suppressing inrush current regardless of the temperature of the surrounding environment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-148511 A Summary of the Invention [Problem to be solved by the invention]

[0005] Machines and equipment used in production sites using FA (Factory Automation) are typically controlled by control devices such as programmable logic controllers (hereinafter also referred to as "PLCs"). A PLC (Programmable Controller) typically includes functional units that handle various processes, such as a CPU (Central Processing Unit) unit that is the main body that executes various programs including control programs, and an I / O (Input / Output) unit that sends and receives signals from the field.

[0006] Generally, the more advanced the function (or performance) of a unit is, the greater the power it consumes. Furthermore, the more units there are, the greater the current consumption of the PLC as a whole. Therefore, the capacity of the power supply device that supplies power to the control device is determined taking into account the power consumption of each unit and the maximum number of units included in the PLC.

[0007] However, generally, the larger the capacity of a power supply device, the higher the cost of designing and manufacturing the power supply device. Furthermore, a power supply device with a large capacity also generates a large inrush current when the control device is turned on.

[0008] An object of the present invention is to provide a technique for suppressing inrush current during start-up of a control system having multiple functional units. [Means for solving the problem]

[0009] A control system according to an example of the present disclosure is a control system for executing a control process for a control target, and includes a plurality of functional units each having a function for executing the control process implemented therein, and a power supply line for supplying a power supply voltage to the plurality of functional units. Each of the plurality of functional units includes a power supply circuit for generating an internal power supply voltage from the power supply voltage supplied to the power supply line, and a capacitor connected to an input of the power supply circuit. The control system further includes a startup circuit configured to sequentially supply the power supply voltage to the power supply circuits of the plurality of functional units with a time lag when the control system is powered on.

[0010] According to this configuration, it is possible to suppress the inrush current at the start of a control system having multiple functional units. The multiple functional units are started in sequence with a time lag. In each functional unit, an inrush current occurs due to charging of an input capacitor, etc. Although the inrush current occurs a number of times corresponding to the number of units, the magnitude of the inrush current generated at one time can be suppressed to the magnitude of the inrush current generated in one functional unit.

[0011] A functional unit according to one example of the present disclosure is a functional unit that constitutes a control system and is implemented with a function for executing control processing for a controlled object, and includes a power supply line for providing a power supply voltage to the functional unit, a power supply input terminal connected to a first end of the power supply line to receive the power supply voltage, a power supply output terminal connected to a second end of the power supply line and configured to be connectable to the power supply input terminal of a subsequent unit that constitutes the control system together with the functional unit, a first power supply circuit that generates an internal power supply voltage from the power supply voltage supplied to the power supply line, a capacitor connected to the input of the first power supply circuit, an internal circuit that receives the internal power supply voltage and performs a function, and a startup circuit configured to first supply the power supply voltage to the first power supply circuit of the functional unit when a power supply voltage is input to the power supply input terminal, and then supply the power supply voltage to the first power supply circuit of the subsequent unit after a time delay.

[0012] This configuration makes it possible to suppress inrush currents when the control system is started up. A power supply voltage is supplied to a functional unit, which then starts up. The functional unit then supplies power supply voltage to the subsequent functional unit. Although an inrush current occurs when each functional unit starts up, the magnitude of the inrush current generated at one time can be suppressed to the magnitude of the inrush current generated in one functional unit.

[0013] The start-up circuit may include a connection unit configured to switch whether or not an input of the first power supply circuit is electrically connected to the power supply line, a control circuit that controls the connection unit, and a second power supply circuit that is connected to the power supply line and supplies an operating voltage for operation of the control circuit to the control circuit. The functional unit may further include a start-up signal generation circuit that generates a start-up signal for instructing the control circuit of the subsequent unit on the timing to start up the connection unit so as to operate the connection unit after the connection unit of the functional unit electrically connects the input of the first power supply circuit to the power supply line, and a signal output terminal for outputting the start-up signal from the start-up signal generation circuit to the subsequent unit.

[0014] According to this configuration, the functional unit in the preceding stage controls the supply of the power supply voltage to the functional unit in the following stage. Therefore, the supply of the power supply voltage to the functional unit in the following stage can be started after the supply of the power supply voltage to the functional unit in the preceding stage has started. Note that the connection unit may be any circuit that enables electrical conduction between the input of the first power supply circuit and the power supply line.

[0015] The connection unit may be a switch provided between the power line and the input of the first power supply circuit. The first power supply circuit may include a start-up signal generating circuit. The start-up signal generating circuit may generate the start-up signal after a start-up time has elapsed since the switch was turned on.

[0016] According to this configuration, the first power supply circuit of the preceding functional unit sends a start-up signal to the succeeding functional unit, which controls the supply of power supply voltage. Therefore, after the start-up of the first power supply circuit of the preceding functional unit is completed (for example, after the charging of the capacitor is completed), the supply of power supply voltage to the succeeding functional unit can be started. Note that the start-up time may be the time it takes for the input voltage of the first power supply circuit to reach a predetermined voltage. Alternatively, the start-up time may be a fixed time.

[0017] The functional unit and the subsequent unit have address values ​​for relatively addressing the functional unit and the subsequent unit with reference to the first unit in the control system. When the address value is given, the control circuit may calculate a waiting time until the connection unit is activated, and activate the connection unit after the waiting time has elapsed. The control circuit may include an activation signal generation circuit. The activation signal generation circuit generates an address value to be assigned to the subsequent unit based on the address value of the functional unit, and generates a signal indicating the address value of the subsequent unit as an activation signal.

[0018] According to this configuration, the control circuit of the functional unit in the front stage sends a start-up signal to the functional unit in the rear stage. The start-up signal is an address value for identifying each functional unit. The address value may be determined according to the connection position of each functional unit in the control system. Since the address value is different for each functional unit, each functional unit starts up the first power supply circuit at a different timing. Therefore, the timing for starting the supply of the power supply voltage can be made different between the functional unit in the front stage and the functional unit in the rear stage.

[0019] The input of the first power supply circuit may be connected to the power supply line. The startup circuit may include a switch provided in the power supply line between the input of the first power supply circuit and the power supply output terminal, a control circuit that controls the switch to turn on the switch in response to a startup signal, and a second power supply circuit that is connected to the power supply line and supplies an operating voltage for operating the control circuit to the control circuit. The first power supply circuit may include a startup signal generating circuit that generates a startup signal when a startup time has elapsed since the start of supplying the power supply voltage to the first power supply circuit.

[0020] According to this configuration, when the first power supply circuit of each functional unit turns on, the power supply voltage is supplied to the functional unit in the next stage. The timing at which the power supply voltage is supplied can be made different between the functional unit in the previous stage and the functional unit in the next stage.

[0021] The input voltage of the first power supply circuit may be a voltage higher than the power supply voltage. The connection unit may include a third power supply circuit activated by an activation signal to convert the power supply voltage into the input voltage of the first power supply circuit and charge the capacitor.

[0022] The input voltage of the first power supply circuit may be higher than the power supply voltage, and the functional unit may further include a third power supply circuit activated by an activation signal to convert the power supply voltage to the input voltage of the first power supply circuit and charge the capacitor. That is, the functional unit may have a third power supply circuit in addition to the connection between the power supply line and the input of the first power supply circuit.

[0023] According to this configuration, the capacitor can be charged by the circuit that holds the input voltage of the capacitor. When the power supply to the control system is turned off, the power supply voltage is not supplied to the power line. However, by using the power stored in the capacitor, the circuit in the functional unit can execute the necessary processing when the power is turned off. Effect of the Invention

[0024] According to the present invention, it is possible to suppress an inrush current at the start-up of a control system having a plurality of functional units. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of a production system including a control system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration related to power supply of the control system according to the present embodiment. [Diagram 3] FIG. 1 is a circuit diagram in which the number of functional units to which the power supply voltage is supplied is one. [Figure 4] FIG. 4 is a diagram showing a change in current in the functional unit shown in FIG. 3. [Diagram 5] FIG. 13 is a diagram showing an example of a configuration in which a power supply voltage is supplied from one power supply unit to a plurality of functional units. [Figure 6] FIG. 6 is a diagram illustrating a modification of the circuit configuration shown in FIG. 5. [Figure 7] FIG. 7 is a diagram showing a change in current across the functional units shown in FIG. 6. [Figure 8] FIG. 2 illustrates a configuration of a functional unit according to the first embodiment. [Figure 9] FIG. 13 illustrates a configuration of a functional unit according to a second embodiment. [Figure 10] FIG. 13 illustrates a configuration of a functional unit according to a third embodiment. [Figure 11]It is a diagram showing a modification example configuration of a functional unit according to the third embodiment. [Figure 12] It is a diagram showing a configuration of a functional unit according to the fourth embodiment. [Figure 13] It is a diagram showing another configuration of a functional unit according to the fourth embodiment. [Figure 14] It is a diagram showing still another configuration of a functional unit according to the fourth embodiment. [Figure 15] It is a diagram showing still another configuration of a functional unit according to the fourth embodiment. **Modes for Carrying Out the Invention**

[0026] Embodiments of the present invention will be described in detail with reference to the drawings. For the same or corresponding parts in the drawings, the same reference numerals are given and the description thereof will not be repeated.

[0027] <A. Application Example> First, an example of a scenario to which the present invention is applied will be described. FIG. 1 is a schematic diagram of a production system including a control system according to an embodiment. The control system according to the present embodiment is provided, for example, in a production line 10 of FA (Factory Automation), and controls a control target. The production line 10 includes control systems 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H. The control systems 1A to 1H are realized by, for example, PLCs.

[0028] The control systems 1A to 1H are connected to a communication device 4. The control systems 1A to 1H can exchange data with each other via the communication device 4. The communication device 4 is a device for realizing the real-time performance required for communication performed in the industrial field, and is, for example, a switch compliant with IEEE 802.1.TSN. Further, the control systems 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H are time-synchronized with each other. For this purpose, each of the control systems 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H has a timer function.

[0029] In the production line 10 shown in Fig. 1, at least one of the control systems 1A to 1H is a control system according to the embodiment. Hereinafter, the control system 1A will be described as the control system according to the embodiment. Note that all of the control systems 1A to 1H may correspond to the control system according to the present embodiment. Furthermore, Fig. 1 is not intended to limit the number of control systems included in the production line 10.

[0030] The control system 1A executes control processing for a field device 5 that is a control target. The control system 1A includes a plurality of functional units in which functions for executing the control processing are implemented. As shown in FIG. 1, the control system 1A includes a CPU unit 101, functional units 201A, 201B, 201C, and 201D, and an I / O unit 300A. The type of the field device 5 is not particularly limited, and may include, for example, a servo motor. The I / O unit 300A exchanges data with the CPU unit 101 in accordance with a protocol for an industrial network, such as the EtherCAT (registered trademark) protocol.

[0031] The functions implemented by each of the functional units 201A, 201B, 201C, and 201D are not particularly limited. For example, the functional units 201A, 201B, 201C, and 201D may include a communication unit. In the example shown in FIG. 1, the functional unit 201D is a communication unit and is connected to the communication device 4 via a network.

[0032] The AC-DC power supply 400A converts an AC voltage into a DC voltage, and supplies the DC voltage as a power supply voltage to the control system 1A. The power supply voltage of the control system 1A is, for example, DC 24V.

[0033] The CPU unit 101 and the functional units 201A, 201B, 201C, and 201D are connected. Thereby, a common internal bus (not shown) is configured for each unit. This internal bus includes a power line. In this embodiment, the power supply voltage is supplied to each of the CPU unit 101 and the functional units 201A to 201D via an internal power line (not shown) inside the control system 1A. That is, the CPU unit 101 and the functional units 201A to 201D are connected in parallel to the power line.

[0034] The control system 1B includes a CPU unit 102, a functional unit 202A, and an I / O unit 300B. Similar to the I / O unit 300A, the I / O unit 300B exchanges data with the CPU unit 102 according to a protocol for an industrial network such as the EtherCAT (registered trademark) protocol. The functional unit 202A is, for example, a communication unit and is connected to a communication device 4 via a network. Similar to the control system 1A, the AC-DC power supply 400B supplies a power supply voltage (for example, DC24V) to each functional unit of the control system 1B.

[0035] <B. Schematic Configuration of Control System and Functional Unit> FIG. 2 is a block diagram showing a configuration related to power supply of the control system according to this embodiment. As shown in FIG. 2, the control system 1A includes a plurality of functional units (CPU unit 101 and functional units 201A to 201D) in which functions for executing control processing for a control target are implemented, and a power line 11 for supplying a power supply voltage to the plurality of functional units. Each of the plurality of functional units includes a power supply circuit (power supply circuits 14A, 24A to 24D) that generates an internal power supply voltage from the power supply voltage supplied to the power line 11, and a capacitor (capacitors 15A, 25A to 25D) connected to the input of the power supply circuit. The control system 1A further includes startup circuits 17A, 27A to 27D configured to sequentially supply a power supply voltage to the power supply circuits of the plurality of functional units with a time difference when power is turned on to the control system 1A.

[0036] The startup circuits 17A, 27A to 27D control the power supply circuits 14A, 24A to 24D so that the power supply voltage is supplied in the order of the CPU unit 101, the functional unit 201A, the functional unit 201B, the functional unit 201C, and the functional unit 201D. In this specification, the functional unit to which the power supply voltage is supplied first among the multiple linked functional units is called the "previous stage unit," and the functional unit to which the power supply voltage is supplied last is called the "next stage unit." The CPU unit 101 corresponds to the "first stage unit" among the multiple functional units in the control system 1A, and the functional unit 201D corresponds to the "last stage functional unit" among the multiple functional units in the control system 1A.

[0037] 2, the basic circuit configuration for supplying power supply voltage is the same for CPU unit 101 and functional units 201A to 201D. CPU unit 101 and functional units 201A to 201D each include power supply lines 11A, 21A to 21D, power supply input terminals 12A, 22A to 22D, and power supply output terminals 13A, 23A to 23D.

[0038] The power supply lines 11A, 21A to 21D are power supply lines for providing a power supply voltage to the CPU unit 101 and the functional units 201A to 201D, respectively. The power supply input terminals 12A, 22A to 22D are connected to first ends of the power supply lines 11A, 21A to 21D, respectively, and receive the power supply voltage. The power supply output terminals 13A, 23A to 23D are connected to second ends of the power supply lines 11A, 21A to 21D, respectively, and are configured to be connectable to power supply input terminals of subsequent units.

[0039] By connecting the CPU unit 101 and the functional units 201A-201D, the power output terminal of the functional unit is connected to the power input terminal of the unit immediately following that unit. This connects the power lines 11A, 21A-21D to form the power line 11. The power input terminal 12A of the CPU unit 101 is coupled to the AC-DC power supply 400A and receives a power supply voltage (e.g., DC 24V). This allows the CPU unit 101 and each of the functional units 201A-201D to receive the power supply voltage through the power line 11.

[0040] The CPU unit 101 and the functional units 201A to 201D each include a power supply circuit 14A, 24A to 24D, a capacitor 15A, 25A to 25D, an internal circuit 16A, 26A to 26D, and a startup circuit 17A, 27A to 27D. The power supply circuits 14A, 24A to 24D (first power supply circuits) generate an internal power supply voltage from a power supply voltage supplied to each of the power supply lines 11A, 21A to 21D. The internal power supply voltage is, for example, DC 5V, DC 3.3V, etc.

[0041] The capacitors 15A, 25A to 25D are connected to the inputs of the power supply circuits 14A, 24A to 24D, respectively.

[0042] The internal circuits 16A, 26A to 26D receive the internal power supply voltage and execute functions for control processing by the control system 1A. Each of the start-up circuits 17A, 27A to 27D is configured to first supply the power supply voltage to the internal power supply circuit of the functional unit including the start-up circuit when the power supply voltage is input to the power supply input terminal, and then supply the power supply voltage to the internal power supply circuit of the subsequent unit with a time difference. In one embodiment, the start-up circuit sends a signal to the start-up circuit of the subsequent unit to start up the power supply circuit. In another embodiment, after the power supply circuit of the previous functional unit is started up, the power supply circuit sends a signal to the start-up circuit of the subsequent unit to start up the power supply circuit.

[0043] According to this embodiment, a time difference is provided in the power supply circuits of a plurality of functional units, and the power supply voltage is sequentially supplied. Thereby, while suppressing an increase in the capacity of the power supply device, it is possible to suppress the inrush current at the time of starting a control system having a plurality of units. This point will be described below.

[0044] <C. Problems Regarding Suppression of Inrush Current> FIG. 3 is a circuit diagram when the number of functional units to which the power supply voltage is supplied is one. FIG. 3 shows a configuration related to the power supply circuit of the CPU unit 101. The AC-DC power supply 401 supplies a power supply voltage (for example, DC24V) to the power supply circuit 14A.

[0045] FIG. 4 is a diagram showing the change in current in the functional unit shown in FIG. 3. When power is supplied to the functional unit (Power ON), the current i rapidly rises and reaches a value (X [A]) larger than the steady-state value. The current that rapidly rises at the time of power-on is called an inrush current. As the capacitor 15A is charged, the current i gradually decreases and reaches the current value (Y [A]) during normal operation of the functional unit.

[0046] One factor causing the inrush current is the charging of the capacitor 15A connected to the input of the power supply circuit 14A. A capacitor 15A having a large capacity is connected to the power supply circuit 14A. When power is supplied to the functional unit, a large current flows instantaneously to charge the large-capacity capacitor. For this reason, an inrush current is generated.

[0047] A large-capacity capacitor is used for capacitor 15A for the following reasons. In highly functional (or high-performance) functional units such as a CPU unit, the power consumption of the CPU or peripheral circuits within the unit is large, and so the power consumption per functional unit is large. Furthermore, in highly functional (high-performance) units, preparations for power-off, such as data protection processing, are required when the power is turned off. Alternatively, the order of power-off must be observed within the functional unit so as not to damage the CPU and peripheral circuits when the power is turned off. Therefore, when the power is turned off, power must be maintained within the functional unit for a certain period of time. To meet this requirement, power must be stored in a capacitor with a large capacity.

[0048] Fig. 5 is a diagram showing an example of a configuration in which a power supply voltage is supplied from one power supply unit to multiple functional units. In the configuration shown in Fig. 5, a power supply voltage (for example, DC 5V) is supplied from power supply unit 40 to CPU unit 101 and functional units 201A to 201C.

[0049] The power supply unit 40 includes a power supply circuit 41, a capacitor 42, and a power supply circuit 43. The output of the power supply circuit 41 is connected to the capacitor 42 and the input of the power supply circuit 43. The power supply circuit 41 is a voltage holding circuit that receives a voltage (e.g., DC 24 V) from an AC-DC power supply 402 and holds the input voltage of the power supply circuit 43 and the capacitor 42. The power supply circuit 43 converts the input voltage into a power supply voltage for the functional units.

[0050] 5, the output capacity of power supply unit 40 depends on the power consumption of the functional units. When the total power consumption of multiple functional units is large (when the power consumption of each functional unit is large, or when the number of functional units is increased), a power supply unit with a large output capacity is required.

[0051] 5, when determining the output capacity of the power supply unit 40, the maximum number of functional units that can be connected or the maximum power consumption must be assumed in advance. However, even if the output capacity of the power supply unit 40 is determined in this way, the actual number of functional units may be significantly smaller than the maximum number of functional units that can be connected. Increasing the output capacity of the power supply unit more than necessary may cause problems in terms of manufacturing costs, size, heat dissipation, and the like.

[0052] Fig. 6 is a diagram for explaining a modified example of the circuit configuration shown in Fig. 5. In the configuration shown in Fig. 6, a plurality of functional units (CPU unit 101 and each of functional units 201A to 201D) have power supply circuits (power supply circuits 14A, 24A to 24D). The power supply circuit of each functional unit generates an internal power supply voltage from a power supply voltage (DC 24V) supplied from an AC-DC power supply 400A. Capacitors (capacitors 15A, 25A to 25D) are connected to the input of the power supply circuit of each functional unit.

[0053] Figure 7 shows the change in current of the entire functional unit shown in Figure 6. Power supply voltage is supplied to multiple functional units at the same time. If the capacity of the power supply circuit (including the capacity of the capacitor) is the same for multiple functional units, the inrush current and the current after normal startup are proportional to the number of functional units. Therefore, the inrush current and the current during normal operation are five times the inrush current (X [A]) and the current during normal operation (Y [A]) when there is one functional unit, respectively.

[0054] Since the inrush current and the consumption current (or power consumption) during normal operation are significantly different, it becomes difficult to select components such as circuit breakers, fuses, filters, etc. provided between, for example, a power supply device or between the power supply device and a control system. Basically, components such as the power supply device and the circuit breaker are selected to have a large capacity. However, the larger the capacity, the higher the prices of the power supply device and the components. Furthermore, when the capacities of the circuit breaker and fuse are determined considering the inrush current, even if a current larger than the normal current is generated during operation, if that current is smaller than the inrush current, the circuit breaker or fuse will not function. This poses a problem in terms of circuit protection.

[0055] In order to suppress the increase in the output capacity of the power supply device, each of the plurality of functional units needs to have a power supply circuit. However, since the plurality of functional units constituting the control system are connected in parallel to the power supply, the inrush current also tends to be large.

[0056] <D. Specific Configuration of Functional Unit According to Embodiment> (Embodiment 1) FIG. 8 is a diagram showing the configuration of a functional unit according to the first embodiment. As shown in FIG. 8, the CPU unit 101 is connected to the AC-DC power supply 400A by the input lines 44 and 45. With the voltage of the input line 45 as a reference (DC0V), the power supply voltage (DC24) is supplied to the input line 44.

[0057] A circuit breaker 46 is inserted into the input lines 44 and 45. A fuse may be inserted into the input line 44 instead of the circuit breaker 46.

[0058] In the CPU unit 101, power input terminals 12A and 111 are connected to input lines 44 and 45. This allows a power supply voltage to be supplied to the power supply line 11. The power supply input terminal 111 is connected to a reference voltage line 112 inside the control system 1A. The reference voltage line 112 is connected to a terminal 121, which is connected to a terminal 221 of the functional unit 201A. The terminal 221 is connected to a reference voltage line 212, which is connected to a terminal 232.

[0059] When a power supply voltage is supplied to the CPU unit 101, the start-up circuit 17A starts up the power supply circuit 14A. The start-up circuit 17A includes a switch 171, a logic circuit (Logic) 172, and a logic power supply circuit 173.

[0060] The switch 171 is a connection unit configured to switch whether or not the input of the power supply circuit 14A is electrically connected to the power supply line 11. The switch 171 is provided between the power supply line 11 and the input of the power supply circuit 14A. As shown in Fig. 8, a resistor 151 for suppressing an inrush current may be disposed between the capacitor 15A and the switch 171. The resistor 151 is connected to the input of the power supply circuit 14A together with the capacitor 15A.

[0061] Logic circuit 172 is a control circuit that controls switch 171. Logic power supply circuit 173 is an operating power supply circuit (second power supply circuit) that is connected to power supply line 11 (power supply line 11A) and supplies an operating voltage for the operation of logic circuit 172 to logic circuit 172. Logic power supply circuit 173 supplies logic circuit 172 with a power supply voltage for the logic circuit (for example, DC 5V).

[0062] Since the power supply voltage is supplied to the logic power supply circuit 173 at the same time as the control system 1A is started, the logic circuit 172 also receives the operating voltage from the logic power supply circuit 173 immediately after the control system 1A is started. Therefore, the logic circuit 172 is started almost at the same time as the control system 1A is started, and turns on the switch 171. This causes the power supply voltage to be supplied to the power supply circuit 14A. Since the capacitor 15A is charged, an inrush current is generated in the CPU unit 101. However, no inrush current is generated in the other functional units.

[0063] The power supply circuit 14A includes a start-up signal generating circuit 141. The start-up signal generating circuit 141 generates a start-up signal SG after the switch 171 of the CPU unit 101 electrically connects the input of the power supply circuit 14A to the power supply line 11.

[0064] The start-up signal SG is a signal that notifies the functional unit 201A that charging of the capacitor 15A is completed. For example, the start-up signal generating circuit 141 may generate the start-up signal SG after a start-up time has elapsed from the time when the switch 171 is turned on. This start-up time may be, for example, the time until the power supply circuit 14A detects that the input voltage of the power supply circuit 14A has reached a preset voltage. Alternatively, the start-up time may be a predetermined time from the time when the switch 171 is turned on. This "predetermined time" can be determined in advance based on a time constant determined by the resistance value of the resistor 151 and the capacitance value of the capacitor 15A.

[0065] The power supply circuit 14A (start-up signal generating circuit 141) outputs a start-up signal SG. The start-up signal SG is output from a signal output terminal 19B to the outside of the CPU unit 101. A signal input terminal 29A of the functional unit 201A is connected to the signal output terminal 19B. Therefore, the start-up signal SG is input to a start-up circuit 27A of the functional unit 201A.

[0066] The start-up circuit 27A includes a switch 271, a logic circuit 272, and a logic power supply circuit 273. The functions of the switch 271, the logic circuit 272, and the logic power supply circuit 273 are basically the same as those of the switch 171, the logic circuit 172, and the logic power supply circuit 173. Since the power supply voltage is supplied to the logic power supply circuit 273 at the same time as the start-up of the control system 1A, the logic circuit 272 also receives the operating voltage from the logic power supply circuit 273 immediately after the start-up of the control system 1A. The logic circuit 272 turns on the switch 271 in response to the start-up signal SG. As a result, the input of the power supply circuit 24A is connected to the power supply line 11, and the power supply voltage is supplied to the power supply circuit 24A. The start-up signal SG from the CPU unit 101 corresponds to a signal for instructing the timing of starting up (turning on the switch) the connection part of the functional unit 201A.

[0067] The power supply circuit 24A includes an activation signal generating circuit 241. Similar to the activation signal generating circuit 141, the activation signal generating circuit 241 generates an activation signal SG when charging of the capacitor 25A is completed. The power supply circuit 24A (activation signal generating circuit 241) outputs the activation signal SG to the outside from the signal output terminal 29B.

[0068] Signal output terminal 29B is connected to a signal input terminal of a subsequent unit (functional unit 201B). As a result, start signal SG from functional unit 201A is input to functional unit 201B. The operation of functional unit 201B after receiving start signal SG is the same as that of functional unit 201A, and therefore the description thereafter will not be repeated.

[0069] Thus, in the first embodiment, when charging of the capacitor of a preceding unit is completed, the preceding unit sends a start-up signal SG to the succeeding unit. The start-up circuit of the succeeding unit starts up the power supply circuit in response to the start-up signal SG. Since the units are started in order from the preceding unit with a time lag, an inrush current occurs a number of times corresponding to the number of units, but the magnitude of the inrush current generated each time can be suppressed to the magnitude of the inrush current of one functional unit.

[0070] (Embodiment 2) Fig. 9 is a diagram showing a configuration of a functional unit according to the second embodiment. In the configuration shown in Fig. 9, the start signal generation circuit is included in the logic circuit. Therefore, the logic circuit generates the start signal SG.

[0071] Specifically, the start signal SG is a signal indicating an address value for identifying the connection position of the functional units in the control system 1A. "Connection position" may be read as "order" or "stage." The address value of each functional unit is a relative value based on the CPU unit 101, which is the unit in the front stage.

[0072] 9, the address value of the CPU unit 101 is set to "00." Since the position of the CPU unit 101 in the control system 1A is predetermined, the address of the CPU unit 101 can be fixed. The logic circuit 172 of the CPU unit 101 notifies the address of the functional unit 201A, which is a subsequent unit, of the address of the functional unit 201A.

[0073] The start signal generation circuit 141 can be realized by an address addition circuit. The address addition circuit adds 1 to the address value "00". Therefore, the address value of the functional unit 201A becomes "01". The start signal generation circuit 141 outputs a signal notifying the address value "01" as the start signal SG from the signal output terminal 19B. Since the signal output terminal 19B is connected to the signal input terminal 29A of the functional unit 201A, the start signal SG is input to the logic circuit 272.

[0074] Logic circuit 272 adds 1 to address value "01" to determine address value "02" of functional unit 201B, and outputs a signal notifying address value "02" as activation signal SG from signal output terminal 29B.

[0075] The logic circuit 272 determines the timing to turn on the switch 271 based on the address value "01" of the functional unit 201A. For example, the logic circuit 272 sets the standby time to a value obtained by multiplying the address value by a predetermined time constant (for example, 500 ms). The logic circuit 272 operates an internal timer and turns on the switch 271 when the set standby time has elapsed.

[0076] The control of the switches in functional unit 201B and the subsequent functional units is similar to the control of switch 271 in functional unit 201A. In the second embodiment, a preceding functional unit notifies a subsequent unit of the address of the subsequent unit. Each functional unit waits for a time corresponding to the address value, and turns on the switch after the waiting time has elapsed. Therefore, the timing of turning on the switch differs between a certain functional unit and a subsequent functional unit by a time corresponding to (increment value of address)×(predetermined time constant). This allows the power supply voltage to be supplied sequentially to the power supply circuits of the multiple functional units with a time difference, so that the inrush current of the entire control system can be suppressed as in the first embodiment.

[0077] In the above embodiment, the preceding functional unit generates the address value of the succeeding functional unit by increasing its own address value. However, the address value of the succeeding functional unit may be generated by subtracting the address value. In this case, the address value of the CPU unit 101 is the largest among the multiple functional units. The timing of turning on the switch between a certain functional unit and the succeeding functional unit may be made to differ by a time equivalent to (absolute value of address decrement value) x (predetermined time constant).

[0078] (Embodiment 3) Fig. 10 is a diagram showing the configuration of a functional unit according to the third embodiment. In the configuration shown in Fig. 10, in each functional unit, the input of the power supply circuit is connected to the power supply line. Furthermore, a switch is provided on the power supply line and between the input of the power supply circuit and the power output terminal. Therefore, the startup circuit of each functional unit is a circuit for supplying a power supply voltage to the power supply circuit of the functional unit next to that functional circuit.

[0079] As in the first embodiment, the start-up signal generating circuit is included in the power supply circuit and generates a start-up signal when the charging of the capacitor is completed. In the third embodiment, the start-up signal is sent to a logic circuit in the functional unit to which the start-up signal generating circuit belongs. In this respect, the third embodiment differs from the first embodiment.

[0080] Specifically, in CPU unit 101, the input of power supply circuit 14A is connected to power supply line 11A. A switch 171 is provided on power supply line 11A, between the input of power supply circuit 14A and power supply output terminal 13A. Similarly, in functional unit 201A, the input of power supply circuit 24A is connected to power supply line 21A. A switch 271 is provided on power supply line 21A, between the input of power supply circuit 24A and power supply output terminal 23A.

[0081] 10, in the CPU unit 101, when charging of the capacitor 15A is completed, the start-up signal generation circuit 141 outputs the start-up signal SG to the logic circuit 172. The logic circuit 172 turns on the switch 171 in response to the start-up signal SG.

[0082] By turning on the switch 171, the power supply voltage is input to the functional unit 201A. Therefore, the capacitor 25A is charged. When the charging of the capacitor 25A is completed, the start-up signal generating circuit 241 sends the start-up signal SG to the logic circuit 272. In response to the start-up signal SG, the logic circuit 272 turns on the switch 271. Note that in the third embodiment, the conditions for determining the timing to generate the start-up signal may be the same as the conditions applied in the first embodiment.

[0083] In the third embodiment as well, the power supply voltage can be sequentially supplied to the power supply circuits of the multiple functional units with a time lag, thereby suppressing the inrush current of the entire control system.

[0084] In the third embodiment, the logic power supply circuit and the power supply circuit are both powered on at the same time, so the configuration shown in FIG.

[0085] Fig. 11 is a diagram showing a configuration of a modified example of a functional unit according to the third embodiment. In the configuration shown in Fig. 11, the start-up signal generating circuits 141 and 241 are omitted from the power supply circuits 14A and 24A, respectively. In this respect, the configuration shown in Fig. 11 differs from the configuration shown in Fig. 10.

[0086] When an operating voltage is supplied from logic power supply circuit 173, logic circuit 172 operates an internal timer. When a preset waiting time has elapsed, logic circuit 172 turns on switch 171. As a result, power is simultaneously applied to both logic power supply circuit 273 and power supply circuit 24A of functional unit 201A.

[0087] When an operating voltage is supplied from logic power supply circuit 273, logic circuit 272 operates an internal timer. When a preset waiting time has elapsed, logic circuit 272 turns on switch 271. The same operation as above is executed sequentially in the units subsequent to functional unit 201A. Therefore, power supply voltages are sequentially supplied to the power supply circuits of the multiple functional units with a time lag.

[0088] (Embodiment 4) The activation method of the functional unit according to the first to third embodiments can also be applied to a functional unit having a power supply holding circuit (third power supply circuit). The power supply holding circuit is a circuit for holding the input voltage of a capacitor connected to the input of the power supply circuit (hence holding the power stored in the capacitor). By providing the power supply holding circuit, it is possible to execute a predetermined process such as data protection when the power supply of the functional unit is turned off. Alternatively, it is possible to turn off the power supply to the CPU and peripheral circuits in a predetermined order. This makes it possible to protect the components inside the functional unit.

[0089] FIG. 12 is a diagram showing a configuration of a functional unit according to the fourth embodiment. As shown in FIG. 12, a CPU unit 101 includes a power supply generating circuit 18. The power supply generating circuit 18 is connected to a power supply line 11A via a resistor 151 and receives a power supply voltage (for example, DC 24V). The power supply generating circuit 18 converts the power supply voltage into an input voltage of a power supply circuit 14A and charges a capacitor 15A (a capacitor for holding electric charge) connected to the input of the power supply circuit 14A. The input voltage of the power supply circuit 14A is a voltage higher than the power supply voltage, for example, DC 50V. The power supply circuit 14A generates a power supply voltage (for example, DC 5V) for an internal circuit from the output voltage (DC 50V) of the power supply generating circuit 18.

[0090] The hold-up power generation circuit 18 is started by the logic circuit 172. When the hold-up power generation circuit 18 is started, the hold-up power generation circuit 18 converts the power supply voltage on the power supply line 11A into an input voltage for the power supply circuit 14A and charges the capacitor 15A.

[0091] When charging of the capacitor 15A is completed, the start-up signal generating circuit 141 in the power supply circuit 14A generates the start-up signal SG and outputs the start-up signal SG to the signal output terminal 19B. The functional unit 201A receives the start-up signal SG via the signal input terminal 29A. The start-up signal SG is input to the logic circuit 272. The logic circuit 272 starts up the hold-up power supply generating circuit 28 in response to the start-up signal SG.

[0092] Like the hold power supply generating circuit 18, the hold power supply generating circuit 28 converts the power supply voltage on the power supply line 21A into an input voltage for the power supply circuit 24A, and also charges the capacitor 25A. When charging of the capacitor 25A is completed, the start signal generating circuit 241 in the power supply circuit 24A generates a start signal SG for starting the hold power supply generating circuit of the subsequent unit, and outputs the start signal SG to the signal output terminal 29B.

[0093] When the hold power generation circuit 18 is started, the power supply circuit 14A receives the input voltage. In the fourth embodiment, the hold power generation circuit 18 is a connection part for electrically connecting the input of the power supply circuit 14A to the power supply line 11A. Therefore, in the configuration shown in FIG. 12, the start-up circuit 17A has the hold power generation circuit 18 as a connection part instead of the switch 171. Similarly, in the functional unit 201A, the start-up circuit 27A has the hold power generation circuit 28 as a connection part instead of the switch 271. In this respect, the fourth embodiment differs from the first embodiment.

[0094] Fig. 13 is a diagram showing another configuration of the functional unit according to the fourth embodiment. As shown in Fig. 13, the switch in the functional unit according to the second embodiment (see Fig. 9) can be replaced with a hold-up power supply generating circuit.

[0095] Fig. 14 is a diagram showing yet another configuration of the functional unit according to the fourth embodiment. As shown in Fig. 14, in the configuration of the functional unit according to the third embodiment (see Fig. 10), a power hold generating circuit may be added between the resistor and the capacitor.

[0096] Fig. 15 is a diagram showing yet another configuration of the functional unit according to the fourth embodiment. As shown in Fig. 15, in the configuration of the functional unit according to the third embodiment (see Fig. 11), a power hold generating circuit may be added between the resistor and the capacitor.

[0097] Similar to the functional unit shown in FIG. 11, in the functional unit shown in FIG. 15, when an operating voltage is supplied from the logic power supply circuit 173, the logic circuit 172 operates an internal timer. When a preset standby time has elapsed, the logic circuit 172 turns on the switch 171. As a result, power is simultaneously supplied to both the logic power supply circuit 273 and the power supply circuit 24A of the functional unit 201A. When an operating voltage is supplied from the logic power supply circuit 273, the logic circuit 272 operates an internal timer. When a preset standby time has elapsed, the logic circuit 272 turns on the switch 271. The same operation as the above-described operation is sequentially executed in units subsequent to the functional unit 201A. Therefore, power supply voltages are sequentially supplied to the power supply circuits of a plurality of functional units with a time difference.

[0098] When the holding power generation circuit charges a capacitor connected to the input of the power supply circuit, a current larger than the current during normal operation is generated. The operation at startup of the functional unit according to the fourth embodiment is the same as the operation of the corresponding functional unit in the first to third embodiments. Therefore, also in the fourth embodiment, since power supply voltages are sequentially supplied to the power supply circuits of a plurality of functional units with a time difference, inrush current can be suppressed.

[0099] <E. Supplementary Note> The present embodiment as described above includes the following technical ideas.

[0100] [Configuration 1] A control system (1A) for executing control processing for a control target, a plurality of functional units (101, 201A to 201D) in which functions for executing the control processing are implemented, and a power supply line (11) for supplying a power supply voltage to the plurality of functional units (101, 201A to 201D), each of the plurality of functional units (101, 201A to 201D) a power supply circuit (14A, 24A to 24D) that generates an internal power supply voltage from the power supply voltage supplied to the power supply line (11); a capacitor (15A, 25A to 25D) connected to an input of the power supply circuit (14A, 24A to 24D); The control system (1A) The control system (1A) further includes a startup circuit (17A, 27A to 27D) configured to sequentially supply power supply voltages with a time lag to the power supply circuits (14A, 24A to 24D) of the plurality of functional units (101, 201A to 201D) when the control system (1A) is powered on.

[0101] [Configuration 2] A function for executing a control process for a control target (5) is implemented in functional units (101, 201A to 201D) constituting a control system (1A), power supply lines (11A, 21A to 21D) for supplying a power supply voltage to the functional units (101, 201A to 201D); power supply input terminals (12A, 22A to 22D) connected to first ends of the power supply lines (11A, 21A to 21D) to receive the power supply voltage; power output terminals (13A, 23A to 23D) connected to second ends of the power lines (11A, 21A to 21D) and configured to be connectable to the power input terminals (22A to 22D) of subsequent units (201A to 201D) constituting the control system (1A) together with the functional units (101, 201A to 201D); a first power supply circuit (14A, 24A to 24D) that generates an internal power supply voltage from the power supply voltage supplied to the power supply line (11A, 21A to 21D); a capacitor (15A, 25A to 25D) connected to an input of the first power supply circuit (14A, 24A to 24D); an internal circuit (16A, 26A to 26D) that receives the internal power supply voltage and executes the function; a startup circuit (17A, 27A to 27D) configured to first supply the power supply voltage to the first power supply circuit (14A, 24A to 24D) of the functional unit (101, 201A to 201D) of the subsequent unit (201A to 201D) with a time lag when the power supply voltage is input to the power supply input terminal (12A, 22A to 22D), and then supply the power supply voltage to the first power supply circuit (24A to 24D) of the subsequent unit (201A to 201D) of the subsequent unit.

[0102] [Configuration 3] The start-up circuit (17A, 27A to 27D) a connection unit (171, 271, 28) configured to switch whether or not an input of the first power supply circuit (24A to 24D) is electrically connected to the power supply line (11A, 21A to 21D); A control circuit (172, 272) for controlling the connection portion (171, 271, 28); a second power supply circuit (173, 273) connected to the power supply lines (11A, 21A to 21D) and supplying an operating voltage for operating the control circuit (172, 272) to the control circuit (172, 272); The functional units (101, 201A to 201D) are an activation signal generating circuit (141, 241) which generates an activation signal (SG) for instructing the control circuit (272) of the subsequent unit of a timing for activating the connection unit (171, 271, 28) so as to operate the connection unit (271, 28) after the connection unit (171, 271, 28) of the functional unit (101, 201A to 201D) electrically connects an input of the first power supply circuit (24A to 24D) to the power supply line (11A, 21A to 21D); The functional unit (101, 201A to 201D) according to configuration 2, further comprising a signal output terminal (19B, 29B) for outputting the activation signal from the activation signal generating circuit (141, 241) to the unit at the subsequent stage.

[0103] [Configuration 4] the connection portion (171, 271) is a switch provided between the power supply line (11A, 21A to 21D) and an input of the first power supply circuit (24A to 24D), The first power supply circuit (24A to 24D) includes the start-up signal generating circuit (141, 241), The functional unit (101, 201A to 201D) according to configuration 3, wherein the start-up signal generating circuit (141, 241) generates the start-up signal (SG) after a start-up time has elapsed from the time the switch is turned on.

[0104] [Configuration 5] the functional units (101, 201A to 201D) and the subsequent units (201A to 201D) have address values ​​for relatively addressing the functional units (101, 201A to 201D) and the subsequent units (201A to 201D) with reference to a front-stage unit (101) in the control system (1A); When the address value is given, the control circuit (172, 272) calculates a waiting time until the connection unit (171, 271, 28) is started, and starts the connection unit (171, 271, 28) after the waiting time has elapsed; The control circuit (172, 272) includes the start signal generation circuit (141, 241), and the start signal generation circuit (141, 241) generates the address value to be assigned to the subsequent unit based on the address value of the functional unit (101, 201A to 201D), and generates a signal indicating the address value of the subsequent unit as the start signal (SG).

[0105] [Configuration 6] the input of the first power supply circuit (24A to 24D) is connected to the power supply line (11A, 21A to 21D); The startup circuit includes: a switch provided in the power supply line (11A, 21A to 21D) between the input of the first power supply circuit (24A to 24D) and the power supply output terminal (13A, 23A to 23D); a control circuit (172, 272) for controlling the switch so as to turn on the switch in response to a start signal (SG); a second power supply circuit (173, 273) connected to the power supply lines (11A, 21A to 21D) and supplying an operating voltage for operating the control circuit (172, 272) to the control circuit (172, 272); The first power supply circuit (24A to 24D) includes: The functional unit (101, 201A to 201D) according to configuration 2 includes a start-up signal generating circuit (141, 241) that generates the start-up signal when a start-up time has elapsed since the start of supply of the power supply voltage to the first power supply circuit (24A to 24D).

[0106] [Configuration 7] The input voltage of the first power supply circuit (24A to 24D) is a voltage higher than the power supply voltage, The connection portion (171, 271, 28) is The functional unit (101, 201A to 201D) according to any one of configurations 3 to 5, further comprising a third power supply circuit (18, 28) that is activated by the activation signal to convert the power supply voltage into an input voltage for the first power supply circuit (24A to 24D) and charge the capacitor.

[0107] [Configuration 8] The input voltage of the first power supply circuit (24A to 24D) is a voltage higher than the power supply voltage, The functional units (101, 201A to 201D) are The functional unit (101, 201A to 201D) according to configuration 6 further includes a third power supply circuit (18, 28) that is activated by the activation signal to convert the power supply voltage into an input voltage of the first power supply circuit (24A to 24D) and charge the capacitor.

[0108] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0109] 1A-1H Control system, 4 Communication device, 5 Field device, 10 Production line, 11, 11A, 21A-21D Power supply line, 12A, 22A-22D, 111 Power supply input terminal, 13A, 23A-23D Power supply output terminal, 14A, 24A-24D, 41, 43 Power supply circuit, 15A, 25A-25D, 42 Capacitor, 16A, 24D, 26A Internal circuit, 17A, 27A-27D Start circuit, 18, 28 Holding power supply generating circuit, 19B, 29B Signal output terminal, 29A Signal input terminal, 40 Power supply unit, 44, 45 Input line, 46 Breaker, 101, 102 CPU unit, 112, 212 Reference voltage line, 121, 221, 232 Terminal, 141, 241 Start signal generating circuit, 151 Resistors, 171, 271 Switches, 172, 272 Logic circuits, 173, 273 Logic power supply circuits, 201A-201D, 202A Functional units, 300A, 300B I / O units, 400A, 400B, 401, 402 AC-DC power supplies, SG Start signal.

Claims

1. A functional unit that configures a control system and has a function for executing a control process for a control target, a power supply line for applying a power supply voltage to the functional unit; a power supply input terminal connected to a first end of the power supply line to receive the power supply voltage; a power output terminal connected to a second end of the power line and configured to be connectable to the power input terminal of a subsequent unit that constitutes the control system together with the functional unit; a first power supply circuit that generates an internal power supply voltage from the power supply voltage supplied to the power supply line; a capacitor connected to an input of the first power supply circuit; an internal circuit that receives the internal power supply voltage and performs the function; a startup circuit configured to supply the power supply voltage to the first power supply circuit of the functional unit in response to a startup signal when the power supply voltage is input to the power supply input terminal, and to provide a startup signal to the subsequent unit for controlling a timing for supplying the power supply voltage to the first power supply circuit of the subsequent unit with a time difference; The startup circuit includes: a connection section configured to switch whether or not an input of the first power supply circuit is electrically connected to the power supply line; A control circuit for controlling the connection unit; a second power supply circuit connected to the power supply line and supplying an operating voltage for the operation of the control circuit to the control circuit; The functional unit comprises: a start-up signal generating circuit that generates the start-up signal for instructing the control circuit of the subsequent unit on the timing of starting up the connection unit so as to operate the connection unit after the connection unit of the functional unit electrically connects the input of the first power supply circuit to the power supply line; a signal output terminal for outputting the start signal from the start signal generating circuit to the subsequent unit; the connection portion is a switch provided between the power supply line and an input of the first power supply circuit, the first power supply circuit includes the startup signal generating circuit, the start-up signal generating circuit generates the start-up signal after a start-up time has elapsed since the switch was turned on; the functional unit and the subsequent unit have address values ​​for relatively addressing the functional unit and the subsequent unit with reference to a first unit in the control system; when the control circuit receives the address value, the control circuit calculates a waiting time until the connection unit is started, and starts the connection unit after the waiting time has elapsed; The control circuit includes the start-up signal generation circuit, which generates the address value to be assigned to the subsequent unit based on the address value of the functional unit, and generates a signal indicating the address value of the subsequent unit as the start-up signal.

2. an input voltage of the first power supply circuit is higher than the power supply voltage; The connection portion is 2. The functional unit according to claim 1, further comprising a third power supply circuit activated by said activation signal to convert said power supply voltage to an input voltage of said first power supply circuit and to charge said capacitor.

Images