KR20100052148A - Intelligent input/output module in plc system - Google Patents

Abstract

PURPOSE: An intelligent input/output module in a plc system is provided to allow a user to decide the operation of a system by enabling a digital module to diagnose a malfunction and block the output by itself. CONSTITUTION: An input-output processing unit(110) outputs various input signal through a relay. The various input signals are offered from CPU inside a PLC system. A level converter(130) detects the signal outputted in the input-output processing unit. The level converter changes the level of the detected signal. A malfunction testing unit(150) compares the output signal of the level converter with the input signal of the input-output processing unit. The malfunction testing unit outputs a diagnosis control signal. A blocking unit(170) blocks a signal outputted from the input-output processing unit according to the diagnosis control signal.

Description

Intelligent input / output module of PLC system {INTELLIGENT INPUT / OUTPUT MODULE IN PLC SYSTEM}

The present invention relates to an intelligent input / output module, and more particularly, to an intelligent input / output module of a PLC system having an output interruption function in the event of an internal circuit failure.

In the programmable logic controller (PLC) system, digital input / output modules are classified and used as a kind of consumables. The use of digital I / O modules to some degree may result in wear or burnout of some important components, which will inevitably require replacement. However, the user does not know when the module needs to be replaced.

At this time, if the module to be replaced has a fault detection function or stops operation on the fault itself, it becomes possible to prepare for diagnosis or breakdown of the fault of the entire system and to replace the module in time. If the entire system is shut down due to sudden failure without notice, unnecessary time, financial and even human damages can occur. However, if a fault can be diagnosed or predicted, and if the module itself stops working when a problem actually occurs, it will not only maximize uptime for the entire system, but also prevent many unnecessary losses.

As the range of PLC applications is expanded due to the continuous increase of factory automation, modules with various functions are being installed. Therefore, as various modules are used, there is a need for a failure diagnosis of each module.

In the case of the digital I / O module which is most used, users can easily check the operation status of the entire system and can use it easily. However, in the case of digital input / output modules, the characteristics of the module have a lifetime limitation. For example, in the case of a relay module, the relay contacts are turned on and off, and sparks are generated between the contacts, which eventually causes the relay contacts to be pressed or the relay switch breaks open. This can cause malfunction of the module.

In the current system, there is no way to diagnose the fault, so the user will not know until the digital module fails.

FIG. 1 is a functional block diagram showing a digital input / output module of a PLC system according to the prior art, and includes an input / output processor 10, a level converter 15, and a gate means 17. As shown in FIG.

The level converter 15 receives the signal output from the input / output processing unit 10 and inverts and outputs the level. The gate means 17 inputs the signal input from the level converter 15 and the input / output processing unit 10. The logic signal is received and the logic is diagnosed.

The signals input to the input / output processing unit 10 are all signals related to the input / output operation in the internal CPU.

That is, when an input signal related to an input / output operation is transferred from the internal CPU of the digital input / output module to the first transistor Q1 of the switch unit 11, the first transistor Q1 is turned on so that the high voltage Vdd is relayed. To be supplied. The switch section 11 is of an open collector type.

As power is supplied to the relay 13, power is applied to the internal coil L1 of the relay 13, whereby the internal switch SW1 is turned on to output a predetermined voltage through the output terminal. .

At this time, the output voltage is input to the level converter 15 by a feedback line connected to the output terminal, and the level converter 15 inverts and outputs the level of the input voltage.

The signal output from the level converter 15 is input to the gate means 17, and the gate means 17 receives a signal input from the level converter 15 and a signal input to the input / output processing unit 10, respectively. The alarm signal is generated after diagnosing a failure according to a predetermined logical operation.

The gate means 17 is an XOR gate, and outputs a 'low' signal when the two input signals are the same, and outputs a 'high' signal when the two input signals are different.

In the case of the digital input / output module configured as described above, the existence of a certain degree of life becomes the biggest problem. In particular, since the electric shock is applied to the output stage a lot of fatigue and cumulative stress of the component is generated accordingly.

In the case of the existing I / O module, once used, it had to be replaced after a certain period of use, and the life time was also not easily understood by the user. In addition, sudden failure of the module while the system is running can cause major problems for the whole process. In addition, if a malfunction occurs due to a module failure, material and human loss is caused. If a system does not shut down quickly in the event of a failure, there are many dangerous situations before the user can take action.

In the prior art as shown in FIG. 1, only a passive method of informing a user of a warning about a failure was used. Thus, there is no way to control malfunctions until the user understands the module's warnings. Eventually, the whole system will be affected, resulting in a lot of losses in an instant.

For example, in the case of a relay module, contacts and switches inside the relay are continuously turned on and off, and sparks are generated therein. The sparks will cause deterioration and excessive stress on the contacts and switches, and if the relays exceed the limit provided by the relays, the contacts and switches will be electrically welded, or the switches will not operate in the off state. do. In particular, since a lot of electric shock occurs, if the switch and the contact is stuck, the failure occurs, and this causes various malfunctions, but it is exposed to a situation where many problems can occur.

The purpose of the present invention is to enable the diagnosis of the fault and output cutoff by the digital input / output module itself, to enable users to determine the operation of the system to some extent, intelligent input and output of the PLC system that can increase the reliability of the entire system To provide a module.

Technical means of the present invention for achieving the above object, the input and output processing unit for outputting a variety of input signals provided from the internal CPU of the PLC system through the relay; A level converter for inverting and level converting the signal output from the input / output processing unit; A failure diagnosis unit for receiving a signal output from the level converter and a signal input to the input / output processing unit, comparing the same, and outputting a failure diagnosis control signal according to the comparison result; And an output blocker which is operated according to the fault diagnosis control signal output from the fault diagnosis unit to block a signal output from the input / output processing unit.

The failure diagnosis unit is characterized in that the XOR gate, characterized in that to output the failure signal to the outside so that the user knows the failure when the failure occurs.

The output blocking unit may be a transistor that blocks an output of the input / output processing unit according to a failure diagnosis control signal of the failure diagnosis unit, and the transistor may be a PNP type or a P-channel transistor.

As described above, the present invention can prevent unnecessary loss from occurring by blocking the output operation by itself in the event of a failure or malfunction of the digital input / output module. By inducing accuracy, it can also have a large influence on securing the reliability of the input / output module itself.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a functional block diagram illustrating a digital input / output module of a PLC system according to the present invention, and FIG. 3 is a circuit diagram illustrating a digital input / output module according to an embodiment of the present invention, and the digital input / output module 100 includes an input / output processing unit 110. And a level converter 130, a failure diagnosis unit 150, and an output interrupting unit 170.

The input / output processing unit 110 is configured to receive various input signals related to input / output operations from an internal CPU of a PLC system and output them through a predetermined relay.

The level converter 130 is configured to detect the signal output from the input / output processing unit 110 and invert the level to output the converted signal.

The failure diagnosis unit 150 receives the signal output from the level converter 130 and the signal input to the input / output processing unit 110, respectively, compares the same, and outputs a diagnostic control signal for the failure as a result of the comparison. Consists of.

The output blocking unit 170 operates according to a diagnostic control signal output from the fault diagnosis unit 150 and is configured to block a signal output from the input / output processing unit 110 when a failure occurs.

The input / output processing unit 110 may be composed of an open collector type switch unit 111 and a relay 115 as shown in FIG. 3.

When an input signal related to an input / output operation is transmitted to the first transistor Q1 from the internal CPU of the digital input / output module, the switch 111 turns on the first transistor Q1 to transfer the high voltage Vdd to the relay 115. To be supplied. In the relay 115, power is applied to the internal coil L1 as the first transistor Q1 of the switch unit 111 is turned on. As a result, the internal switch SW1 is turned on to output the output terminal. The predetermined voltage is output.

The level converter 130 has a configuration such as a photocoupler that detects a signal output through an output terminal (Output) and inverts and outputs the level of the detected signal. The photocoupler of the level converter 130 and the relay 115 of the input / output processing unit 110 physically isolate the input / output terminals of the input / output module 100 to serve as a protection circuit.

The failure diagnosis unit 150 receives a signal output from the level converter 130 and a signal input to the input / output processing unit 110, compares each signal, detects whether a failure occurs, and then outputs a signal for failure. . The fault diagnosis unit 150 is an XOR gate means 17. The XOR gate means 17 outputs a 'low' signal when the two input signals are the same, and outputs a 'high' signal when the two input signals are different. When the two input signals are different from each other, it is recognized that a failure occurs in the input / output processing unit 110.

The output blocking unit 170 operates according to a failure occurrence signal output from the failure diagnosis unit 150 to open a output line, so as to cut off a signal output from the input / output processing unit 110 as a switching element such as a transistor or a relay. Consists of When the output blocking unit 170 is configured as a transistor, the output blocking unit 170 is preferably a PNP type or P-channel transistor which is turned off when a 'high' signal is input.

In the case of the relay 115, it is preferable to select a device that is robust against internally generated sparks, and the level converter 130 may select a high input level.

Looking at the operation of Figure 3 configured as described above is as follows.

When the internal CPU of the digital input / output module 100 sends an input signal related to an input / output operation to the first transistor Q1 of the input / output processing unit 110, the first transistor Q1 is determined to be turned on or off according to the input signal and thus relayed. The power supplied to the 115 is controlled.

If the signal input to the first transistor Q1 is a 'high' signal, the first transistor Q1 is turned on to supply power to the relay 115, and accordingly, the coil L1 inside the relay 115 is supplied. Power is applied to the coil L1 and the contact of the internal switch SW1 of the relay 115 is turned on by the coil L1.

As the relay 115 is turned on, the output terminal of the input / output processing unit 110 is pulled down to a low potential to output a 'low' signal. In FIG. 3, the switch SW2 of the output blocking unit 170 is initially turned on. If the relay 115 fails, a signal unrelated to the input signal will be output through the output.

Subsequently, the level converter 130 detects the signal output through the output terminal and inverts the signal level, and the converted signal is input to the XOR gate which is the failure diagnosis unit 150.

The failure diagnosis unit 150 receives and compares a signal input from the level converter 130 and a signal input to the input / output processing unit 110 and outputs a failure diagnosis signal according to the comparison result. Here, the failure diagnosis unit 150 outputs a 'low' signal when the two input signals are the same, that is, there is no abnormality. However, when the two input signals are different, that is, when there is an error in the input / output processing unit 110, the failure diagnosis unit 150 provides a high signal to the output blocking unit 170 to indicate whether a failure occurs.

When the failure occurrence signal is output from the failure diagnosis unit 150, the output blocking unit 170 turns off the switch SW2 to immediately block the signal output from the input / output processing unit 110.

Conventionally, as shown in FIG. 1, when the failure occurs, the gate means 17 simply informs the user of the failure, but in the present invention, when the failure of the input / output processing unit 110 occurs, the output of the relay 115 is automatically cut off within a short time. do. In addition, the failure diagnosis unit 150 may drive a device such as an alarm or a monitor so that a user may know whether the input / output module 100 is broken, instead of only controlling the operation of the output blocking unit 170 when a failure occurs.

As the switch SW2 constituting the output blocking unit 170, it is preferable to use an electrical switch, not a mechanical switch. This is because the mechanical switching time is slower than the electrical switch.

In FIG. 3, there is only one switch SW2 of the output blocking unit 170, but in practice, the number of switches may be configured according to the number of input / output ports, and the failure diagnosis unit 150 may be configured as an OR gate. It is also possible to construct a circuit that can stop the operation if any one of the parts is abnormal.

In the present invention, when a malfunction of the input / output module occurs, before the user recognizes the malfunction of the input / output module, the input / output module first blocks the output, thereby preventing unnecessary loss. In a general situation, the switch SW2 of the output blocking unit 170 is always turned on to produce a normal output. However, when a failure occurs, the switch SW2 is turned off to block the output of the input / output processing unit 110, and then the user has a failure. You will be informed.

Therefore, in the present invention, when a failure of the input / output module occurs, the user is not informed in a passive manner by a simple alarm method, but in case of a malfunction, the input / output module itself blocks the operation to ensure stability. Since the input / output module itself has an output disconnect function, the overall system can be stabilized and reliability can be increased.

Preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit of the present invention. Therefore, such modifications, changes and additions should be determined not only by the claims below, but also by equivalents to those claims.

1 is a functional block diagram showing a digital input / output module of a PLC system according to the prior art.

2 is a functional block diagram illustrating a digital input / output module of a PLC system according to the present invention.

3 is a circuit diagram illustrating a digital input / output module according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

100: digital input / output module 110: input / output processing unit

111: switch unit 115: relay

130: level converter 150: troubleshooting section

170: output cutoff

Claims (6)

An input / output processing unit for outputting various input signals provided from an internal CPU of the PLC system through a relay; A level converter for inverting and level converting the signal output from the input / output processing unit; A failure diagnosis unit for receiving a signal output from the level converter and a signal input to the input / output processing unit, comparing the same, and outputting a failure diagnosis control signal according to the comparison result; And And an output blocker which is operated according to the fault diagnosis control signal output from the fault diagnosis unit to block a signal output from the input / output processing unit. The method of claim 1, Intelligent fault input / output module of a PLC system, characterized in that the fault diagnosis unit is an XOR gate. The method according to claim 1 or 2, The output blocking unit is an intelligent input / output module of a PLC system, characterized in that the transistor for blocking the output of the input and output processing unit according to the failure diagnosis control signal of the failure diagnosis unit. The method of claim 3, wherein Intelligent transistor module of the PLC system, characterized in that the transistor is a PNP type or P-channel transistor. The method according to claim 1 or 2, The fault diagnosis unit intelligent input / output module of a PLC system, characterized in that for outputting a fault occurrence signal to the outside so that the user can know whether the fault. The method according to claim 1 or 2, Intelligent input / output module of a PLC system, characterized in that the level converter is a photocoupler.

Images