KR20100125721A - Plc system and method for operating the same - Google Patents

Abstract

PURPOSE: A PLC system and a method for operating the same are provided to simultaneously output all output data to all low level devices through a plurality of output modules. CONSTITUTION: A PLC system comprises a plurality of loads(300-1~300-n), a plurality of output modules(200-1~200-n), and a CPU module(100). The plural output modules correspond to the plural loads respectively. The CPU module controls the plural module which output data each load at the same time.

Description

PLC system and driving method using it {PLC SYSTEM AND METHOD FOR OPERATING THE SAME}

The present invention relates to a programmable logic controller (PLC) system and a driving method thereof, and more particularly, to data output synchronization of a PLC system.

In traditional industrial sites, automation equipment consisted of mechanical equipment using relays. In order to change the function of the automated equipment, which is a mechanical device, there was a difficulty in rewiring the internal circuit of the equipment. PLC was created to solve this problem.

The PLC is a programmable logical controller. The PLC generally acts like a computer. It receives signals from the facility and processes them as programmed inside, then outputs the processed signals to the facility. PLC replaces the functions of control devices such as relays, timers, and counters with semiconductor devices such as integrated devices and transistors, and adds arithmetic functions to basic sequence control functions, and enables program control. According to the predetermined logic. PLC can be applied to various tasks such as device control, device numerical setting, time control, real-time monitoring, real-time data collection, and safety device operation.

The PLC system includes a module having various functions in one base and a central processing unit (CPU) for controlling these modules. Among each module is an output module that delivers the data processed by the CPU to each load. Here, the load is a device in the lower stage for finally performing a function, for example, a limit switch, a sensor, and the like. The problem of driving the PLC system is that it takes a considerable time for the data to be transferred to the final load because the data transmitted from the CPU to each output module is not synchronized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a PLC system for outputting all output data to the lower all devices at the same time when the CPU of the PLC system performs input / output control.

The present invention provides a plurality of loads; A plurality of output modules corresponding to the plurality of loads, respectively; And a CPU module for controlling the plurality of output modules such that the plurality of output modules can output data to the corresponding loads substantially simultaneously.

In addition, the CPU module of the present invention groups the plurality of output modules so that the grouped output modules can be controlled so that data can be output to the corresponding load substantially simultaneously, and the data can be sequentially output to the loads between the groups. To control.

In addition, the present invention provides a method of driving a PLC system having a CPU module and a plurality of output modules, the method comprising: transferring data from the CPU module to the plurality of output modules; The CPU module transferring output commands to the plurality of output modules; And outputting data received by the plurality of output modules to a corresponding load at substantially the same time.

The present invention may further include transmitting a response signal to the CPU module in response to the output command.

The transferring of data from the CPU module to the plurality of output modules may include: transmitting a synchronization command from the CPU module to the plurality of output modules; Outputting, by the plurality of output modules, a first response signal to a CPU module in response to the synchronization command; And transferring data to the plurality of output modules.

The transmitting of the data to the plurality of output modules may include: transmitting, by the output module, a second response signal to the CPU model in response to data transmitted from the CPU module; Retransmitting data from the CPU module to the output module if the second response signal does not occur normally; And if the third response signal does not occur in response to the retransmitted data, determining that there is an error in the output module.

The transferring of data from the CPU module to the plurality of output modules may be performed by sequentially providing data to the plurality of modules.

In addition, the CPU module groups the plurality of output modules, and the output commands are output for each group, whereby the grouped output modules output data to corresponding loads according to corresponding output commands.

By utilizing the PLC system according to the present invention, it is possible to facilitate the operation synchronization process of each process or various control objects in the industrial field. PLC systems can be used in industrial sites where fine and delicate processes and synchronization are essential.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. do.

The present invention is characterized in that in the CPU of the PLC system to control the input and output, all the output data is output at the same time to all the lower devices. This makes it easy to synchronize all the subdevices of each PLC system and each drive step.

1 is a block diagram showing a method when a PLC system outputs data.

Referring to FIG. 1, the CPU module 10 of the PLC system has data to be finally output to the loads 1 to n (30_1 to 30_n), and first outputs the output data 1 to the first output module 20_1. After receiving this data normally, the output module 1 (20_1) sends a response signal (Ack1), which is a signal indicating that the data was received normally, to the CPU module (10). Subsequently, the CPU module 10 outputs the output data 2 to the output module 2 20_2. The output module 2 (20_2) outputs a response signal (Ack2) to the CPU module 10 after receiving this data normally. This process is repeated up to the nth output module 20_n. Each output module 20_1 to 20_n outputs data received from the CPU module 10 to a corresponding load. Here, the load is the devices in the lower stage to finally perform the function, for example, limit switch, sensor.

FIG. 2 is a flowchart showing the data output method shown in FIG. 1 in detail.

Referring to Figure 2, first, the CPU module is in the output refresh state. Then, data is sent to the output module 1. The output module 1 receives the data normally and outputs the response signal Ack1 to the CPU module, and then the output module 1 outputs the data received to the corresponding load 1. Subsequently, the CPU module delivers data to the output module 2. If the CPU module does not normally receive the response signal Ack1 from the output module 1, it retransmits the data to the output module 1 again, and if the output module 1 is normally received, it outputs the data transmitted to the corresponding load 1. If the output module 1 does not receive data normally, the CPU module determines that the output module 1 is abnormal.

Subsequently, when the output module 2 normally receives data from the CPU module, the output module 2 outputs a response signal Ack2 to the CPU module correspondingly. The CPU module continues to perform the above-described process corresponding to each output module to the nth output module (see steps A and B). Finally, the CPU module delivers data to the nth output module, and output module n responds. When outputting the data transmitted to the load, the CPU module terminates the output refresh state.

3 is a block diagram illustrating a problem according to a data output method of the PLC system shown in FIG. 1.

As shown in FIG. 3, the CPU module first transmits to the output module 1, and the output module 1 outputs the data received from the load 1. At this time, let x be the time it takes to perform the scheduled operation using the data received from the load. Then, the nth load corresponding to the nth output module receives the data and the delay time for performing the predetermined operation becomes nx + α. Where α represents the required time other than the time that the load operates. The reason for the delay time as described above is that the delay occurs because the output module sequentially outputs data to the corresponding load.

The data output method of the PLC system described so far has a problem that the operation time takes too much time because the synchronization is not performed when each output module outputs data to each load. To solve this problem, the present invention proposes a PLC system capable of synchronizing when each output module outputs data to a corresponding load.

4 is a block diagram showing a method when a PLC system outputs data according to a preferred embodiment of the present invention.

Referring to FIG. 4, the CPU module 100 has data to be transmitted to each output module 200_1 to 200_n, and first outputs a synchronization command to each output module 200_1 to 200_n. Accordingly, each output module 200_1 to 200_n outputs a response signal Ack0 to the CPU module. Subsequently, the CPU module transmits output data corresponding to each output module 200_1 to 200_n, and each output module 200_1 to 200_n outputs a corresponding response signal Ack0 to Ackn to the CPU module. Subsequently, the CPU module transmits an output command to all the output modules 200_1 to 200_n, and each output module 200_1 to 200_n outputs data received from the CPU module to the corresponding loads 300_1 to 300_n, respectively. . The output modules 200_1 to 200_n output a response signal Ackx corresponding thereto after outputting data to the CPU module. Here, as described above, the devices in the lower stage for finally performing a function are, for example, a limit switch and a sensor.

FIG. 5 is a flowchart showing the data output method shown in FIG. 4 in detail.

Referring to Figure 5, first, the CPU module is in the output refresh state. Subsequently, the synchronization command is transmitted to all output modules 200_1 to 200_n, and each output module 200_1 to 200_n outputs a response signal Ack0 to the CPU module 100. If the CPU module 100 does not receive the response signal Ack0, it retransmits the synchronization command. In this case, if the CPU module 100 receives the response signal Ack0, it transmits data to the output module 1, and if not, it is determined that there is an error in the output module.

Continuing with reference, the CPU module 100 transmits data to the output module 1 and receives a response signal Ack1. If the response signal Ack1 is not transmitted to the CPU module 100, the CPU module 100 transmits the data. Resend to output module 1. Also in this case, if the response signal Ack1 is not transmitted to the CPU module 100, the CPU module 100 determines that the output module 1 has an error. When the response signal Ack1 is transmitted to the CPU module 100, the CPU module 100 outputs data to the output module 2. In this process, after the CPU module 100 outputs data to the nth output module 200_n, the CPU module 100 transmits the synchronized output commands to all the output modules 200_1 to 200_n. The output modules 200_1 to 200_n substantially transmit data in synchronization with the corresponding load in response to the synchronized output command, and transmit a response signal Ackx to the CPU module. When the CPU module receives the response signal Ackx, the output refresh state ends.

In this process, the CPU module may transfer data to each output module in consideration of the transmission time delivered according to the position of each output module.

In addition, the position of each output module may be located at a different distance from each other, the CPU module, in this case, group the output modules suitable for achieving synchronization. When data is transferred from the grouped output modules to the load, the data is synchronized. If the data is grouped in different groups, the data is sequentially transmitted.

FIG. 6 is a flowchart illustrating when output modules are grouped in performing the data output method of FIG. 4.

As shown in FIG. 6, a method of grouping output modules and synchronizing output timings of data of the grouped output modules, first, when the synchronization is confirmed, goes to the synchronization command state, and if the synchronization is not confirmed, Output sequence is executed with the same output command, and output module in PLC system outputs data to load sequentially. In the synchronous command state, it is determined whether or not to give a group command to the grouped output modules. When the group command is issued, the grouped output modules are synchronized in the group synchronization command state, and when there is no group command, the entire output module is synchronized.

As described above, the PLC system according to the present embodiment adds a flow for an output synchronization command when multiple output modules (digital input / output or analog input / output) control output of different devices and the same device. Qualitatively all loads can be controlled at the same time. Therefore, it is possible to facilitate the synchronization process of each process and the control object where the PLC system according to the present embodiment is arranged. In other words, the PLC system can be usefully used in the industrial field where minute and delicate processes and synchronization are required.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the scope of the appended claims, as well as the appended claims.

1 is a block diagram showing a method when a PLC system outputs data.

FIG. 2 is a flowchart showing the data output method shown in FIG. 1 in detail. FIG.

3 is a block diagram showing a problem according to the data output method of the PLC system shown in FIG.

4 is a block diagram showing a method when a PLC system outputs data according to a preferred embodiment of the present invention.

FIG. 5 is a flowchart showing in detail the data output method shown in FIG. 4; FIG.

FIG. 6 is a flowchart showing when output modules are grouped in performing the data output method of FIG. 4; FIG.

Explanation of symbols on the main parts of the drawings

100: CPU module 200_1 to 200_n: output module

300_1 to 300_n: Load

Claims (8)

Multiple loads; A plurality of output modules corresponding to the plurality of loads, respectively; And A CPU module controlling the plurality of output modules such that the plurality of output modules can output data to a corresponding load substantially simultaneously, respectively PLC system having a. The method of claim 1, The CPU module groups the plurality of output modules so that the grouped output modules control the data to be output to the corresponding load substantially simultaneously, and control the data to be sequentially output to the load between the groups. PLC system, characterized in that. In a method of driving a PLC system having a CPU module and a plurality of output modules, Transferring data from the CPU module to the plurality of output modules; The CPU module transferring output commands to the plurality of output modules; And Outputting the data received by the plurality of output modules to a corresponding load at substantially the same time; PLC system comprising a. The method of claim 3, wherein The step of transferring data from the CPU module to the plurality of output modules Transmitting a synchronization command from the CPU module to the plurality of output modules; Outputting, by the plurality of output modules, a first response signal to a CPU module in response to the synchronization command; And PLC system comprising the step of transmitting data to the plurality of output modules. The method of claim 3, wherein And transmitting a response signal in response to the output command to the CPU module. The method of claim 4, wherein Transmitting, by the output module, a second response signal to the CPU model in response to data transmitted from the CPU module; Retransmitting data from the CPU module to the output module if the second response signal does not occur normally; And And determining that there is an error in the output module if a third response signal does not occur in response to the retransmitted data. The method of claim 3, wherein The transferring of data from the CPU module to the plurality of output modules is a PLC system, characterized in that to sequentially provide data to the plurality of modules. The method of claim 3, wherein The CPU module groups the plurality of output modules, and the output commands are output for each group, and the grouped output modules accordingly output data in synchronization with a corresponding load according to a corresponding output command. system.

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