KR20020064041A - Out put device using serial communication of triple type control device and control method thereof - Google Patents

Abstract

PURPOSE: An output device using serial communication in a triplicated control system and a method for controlling the same are provided to configure an output circuit free from the bottleneck state of output signals in a multiplexing control system and to offer a flexible logic to select one of two or one of one. CONSTITUTION: Main controllers(200-202), triplicated, are respectively connected with the CPUs(206-208) of output devices through signal lines(203-205) so that serial communication can be made independently. The CPUs(206-208) exchange the output data received from their respective main controllers(200-202) each other through serial communication lines(209-211). Also the CPUs(206-208) exchange data with their respective relay driving boards(215) and other signal processing boards through data/address buses(212-214).

Description

Out put device using serial communication of triple type control device and control method

The present invention relates to an output device using serial communication of a triple control device and a control method thereof, and in particular, eliminates bottlenecks of output signals, minimizes wiring, and provides flexibility in output selection logic (two or two out of three). Of the output device using the serial communication of the triple control device and the control method thereof, which can prevent the high potential of the load from entering the rack of the control device. will be.

The triple control unit consists of three main controllers performing the same control operation, and each controller gives its own output.

The need for an output selection circuit is that devices that receive signals, such as magnetic contactors, solenoids, relays, etc., only allow input to a single coil and to prevent the output of a failed controller from unintentionally opening or closing the output device. For so-called breakdown cover.

As the prior art of the device for controlling the output of the triplex control device, 'selective control circuit of the triplex device' (application number: 10-1995-0052269), 'I / O multiplexed PLC system' (application number: special 1999-036567) And multiplexing control devices and their recovery methods (application number: S. 1998-008129).

The 'selection control circuit of the triplexing device' implements a majority rule of 'matching two of three' in a hardware configuration, and the basic logic is output to the tripled inputs A, B, and C. It is determined in the form of logic. Two controllers must be healthy at all times to produce the correct output, and since there is only one final selection circuit, if this circuit fails, the multiplexed controller itself cannot guarantee the correct output.

In addition, since the output of the selection circuit is three, the output itself of the selection circuit becomes meaningless unless the device to be controlled is tripled. That is, if there is no device that can be selected as the output of the three selection circuits, the realization becomes impossible. If only one device to be controlled has a problem that another type of interface device is required.

The technology implemented in the I / O multiplexing PLC system is characterized by the triple input and the dual output, but the main operation unit (CPI) is duplicated in the same rack and uses the same backplane, so it is not a complete triple control device. There is this.

In other words, it can be called multiplexing of simple input / output. The output section features dual output devices blocked by diodes, readback devices that read each state by themselves, and an auxiliary output signal to completely isolate the failed output from the load.

Disadvantages of this method include first, output wiring including external diode, leadback wiring for feedback of input state, auxiliary output wiring for interrupting output, and second, input for leadback of state. I / O points increase, such as the addition of an additional output and an auxiliary output for blocking output. Third, since only two randomized output devices are used, they are not uniform in terms of reliability of the system and have different utilization rates. .

The technique implemented in the multiplexing control device and its fault recovery method relates to a method of detecting a fault in one of the control devices in a multiplexing control system having a short control period and returning the detected control device to a normal state. The final output of the system is limited to width modulated pulses.

In the final output method, the output signal is determined based on the majority decision principle by combining the output signal through the output buffer and the synchronous control signal.

The disadvantage of this output method is that there is only one majority circuit, which can cause a bottleneck of reliability.

In other words, even if the operation device or input device is normal, if the final output circuit fails, the control cannot be continued anymore. This phenomenon is not limited to the output of the pulse. The same problem may occur.

In the prior art as described above, since the logic of the digital output signal is composed of two out of three, the logic is configured in hardware, so if one fails, the output operates normally. If this output is related to the stop of operation, there is a problem that the operation stops unexpectedly.

Another problem is that with a large number of digital outputs, if there are separate output majority circuits, the number of wires to carry these signals increases, so the majority circuit uses low voltage level signals as logic circuits. There was a problem that becomes vulnerable to noise.

Accordingly, the present invention for solving the above problems constitutes an output circuit without a bottleneck of the output signal in the multiplexing control system, and in general, the majority of circuits used in the output circuit of the multiplexing system should be healthy in two out of three If two outputs are output and two are broken, undesired control may be interrupted unintentionally. In order to prevent this, one of two can be safely stopped at the discretion of the driver without blocking the output even if two are broken. Or one of one to provide flexible selection logic.

The present invention for achieving the above object,

A tripled main controller which outputs a control signal for control and monitoring of the load side and independently communicates with the CPI of the output device by using a signal line for the digital output;

The CPI has a plurality of CPIs respectively connected to the main controller through the signal line, and the CPI is connected to exchange output information of the master controllers received using a separate serial communication line, and the CPI is driven through a data / address bus. An output device configured to exchange data with a board and other signal processing boards;

Characterized in that consisting of.

The relay drive board has a unique address and receives data from the CPI via the data / address bus, transmits only the output data corresponding to its address to the drive circuit through the signal line, and according to the command from the CFI. Or a logic element for blocking or forcibly driving the output to the driving circuit when a failure is detected by an independent determination, and the output of the driving circuit is configured to be connected to the relay terminal board through a signal line.

The relay-terminal block board is configured to drive relays by receiving relay drive signals from each output device using connectors for the configuration of hard-wired logic, and each relay selects two out of three using two contacts. It is characterized in that the load is driven by the power supply when two of the three relays operate normally by configuring a logic circuit.

As a control method of the configured output device,

A first step of checking the state of the upper main controller in a state in which each of the CPIs share data through communication with CPIs of the upper and multiplexed output devices;

A second step of determining that the upper controller is sound when data is received from the main controller at regular intervals;

A third step of identifying a number of higher level controllers currently operating in a healthy state according to the determination of the second step and determining a method of selecting output data according to the result;

A fourth step of selecting an output using two of three selection logics if all three upper controllers are sound as a result of the determination of the third step;

A fifth step of indicating that a failure is detected by one host controller as a result of the third step and determining a final output from the two healthy data;

As a result of the determination in the third step, if two failures of the upper controller are detected, the controller displays the error and informs the driver whether to continue the operation or the data of the sound controller according to the preset operation condition (whether to continue to operate with one healthy main controller). Determining a output power as a sixth step; It characterized in that proceeds to.

1 is a view showing an output device of the triple control apparatus of the present invention.

2 is a circuit diagram showing a relay driver applied to the present invention.

Figure 3 is a circuit diagram showing an output board applied to the present invention.

4 is a flowchart showing a control process of the present invention.

5 is a flowchart showing the output algorithm of the logic element in the relay drive board applied in the present invention.

6 is a control panel configuration diagram of a turbine control system to which the output device of the present invention is applied.

Explanation of symbols for main parts of the drawings

200, 210, 202: Main controller

203, 204, 205: signal line

206, 207, 208

209, 210, 211: signal line

212, 213, 214: data / address bus

215: relay drive board 217: logic element

218: relay drive circuit 220: relay terminal board

224, 225, 226: relay

227: hardwired logic circuit

228: load driving power

229: load

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, FIGS. 1 to 6.

Fig. 1 shows the output device of the present invention, wherein the tripled main controllers 200, 201, and 202 use the signal lines 203, 204, and 205 for the digital output, and the CPI of the output device. CPI is connected to serial communication independently, and CPI configured in each output device exchanges output information received from each main controller 200 to 202 using separate serial communication lines 209, 210 and 211. It was configured to.

In addition, the CPIs 206 to 208 of the respective output devices may exchange data with the relay drive board 215 and other signal processing boards through the data / address buses 212, 213, and 214.

2 shows the configuration of the relay drive board 215.

The CPIs 206, 207, and 207 of the output device write the output data to the relay drive board through the data / address bus 216.

The logic element 217 of the relay driving board has a unique address and transmits only the output data corresponding to its address to the driving circuit 218 through the signal line 230, and the logic element 217 is an output device. If a fault is detected according to the command sent from the CFI of the or independently, the output to the driving circuit is cut off or forcedly driven.

The output of the drive circuit 218 is connected to the relay terminal board via the signal line 219.

FIG. 3 is a relay-terminal block board that receives relay driving signals 221, 222, and 223 from each output device using a connector to configure hard-wired logic, and drives relays 224, 225, and 226, respectively.

Each relay constitutes two logic circuits 227 out of three using two contacts.

In this configuration, when two of the three relays operate normally, the load 229 is driven through the power source 228.

4 is a flowchart of a process relating to a failure detection and output selection method in the CPI of an intelligent output device.

This flow chart begins with each CPI 206-208 already sharing data through communication with the CPI of the upper and multiplexed output devices.

First, check the state of the upper main controller (200 ~ 202) (S1).

Conventional methods use a hardware synchronization signal or a heartbeat signal (heartbeat) that emits a pulse signal with a constant frequency when the controller is healthy, but the present invention replaces it by using serial communication transmitted at a constant period instead. .

That is, when data is received from the main controllers 200 to 202 at regular intervals, the CPIs 206 to 208 of the output device determine that the upper main controllers are sound, and thus a separate signal line of hardware is not required.

Each CPI of the output device checks the number of the presently healthy upper controller through the confirmation of the above state and determines the method of selecting the output data from the result (S2).

That is, when all three upper controllers 200 to 202 are sound, the output is selected by two of the normal three selection logics (S6).

If one host controller detects a failure (S3), the final output is determined from the two healthy data (S6).

If two faults of the upper controller are detected (S4), this is indicated and the driver is notified whether the operation is to be continued (S5) or if the condition of the sound controller is maintained according to a preset operating condition (whether to continue operation with one healthy main controller). The data is determined as an output (S7) or the output is interrupted and the operation is stopped (S8).

By diversifying the fault detection and output selection methods as described above, the data of the failed controller is cut off from the output so that the effect of the failure is not spread to the control target. The driver can decide whether to continue driving without having to do so, so that the driver can stop safely or avoid unnecessary stops.

The output data thus determined is finally output through the relay drive board.

5 is a flowchart of signal processing relating to output logic in the logic element 217 of the relay drive board.

The logic elements 217 in the relay drive board 215 are connected to a common data-address bus 212 for data transfer with the CPIs 206 to 208 of the output device.

The CPIs 206 to 208 of the output device write the output data periodically through the bus 212.

Accordingly, the logic element 217 of the relay driving board 215 checks whether data arrives within a limited time (S10) and determines whether its output device is sound. If the data does not arrive within the limited time, it is determined that the own CPI (206 to 208) has failed and displayed it (S11), and resets its output data (S12).

Thereafter, instead of a complete stop, the flow chart automatically returns when data reception is resumed while the data is in the standby state again according to S13.

When data arrives within the limited time, the data is output (S14) and the process is repeatedly performed.

This logic is characterized by the fact that even if the host controller fails, it participates in the determination of the final output if it is sound and shuts itself down on its own failure including loss of control power so that the failed controller does not affect the final output. It works.

As described in the above description, the present invention uses a method of transmitting output data to an intelligent digital output device having CPI on its own by using serial communication, instead of directly outputting the majority circuit through the digital output device from the main controller in charge of operation. According to this, the wiring from the tripled controller can be minimized, and each tripled main controller has its own output device and selects each output. Therefore, even if one output device fails, the output can be continuously output. have.

In addition, instead of constructing a logic circuit directly for each digital signal to select a majority of votes, a plurality of outputs are selected by software by receiving output data from another digital output device using a separate serial communication. The CPI of the digital output device can determine the health of the upper main computing device or other digital output device through the inspection of the communication status, which is a synchronization signal or a heartbeat signal (periodic clock signal) through the existing hardware signal line. By means of the controller, the controller can replace a signal that transmits soundness to the outside.

The CPI of the digital output device determines how many host controllers or other output devices, including itself, are healthy and selects the output using two out of three logics or one out of one accordingly.

The present invention operating as described above can be applied to you.

For example, the control and monitoring of steam turbines in thermal power plants is of paramount importance in terms of their importance as a power plant and the protection of expensive turbines. In addition, the shutdown of the turbine signifies the interruption of power generation, so it is necessary to continue operation whenever possible to maximize the utilization of the facility.

For this reason, triple control systems are used to control and monitor steam turbines. In the case of a turbine control system that monitors and controls not only the main equipment but also related auxiliary equipment, the input / output score reaches hundreds of points, and in particular, the digital outputs such as relays, solenoid valves, and magnetic contactors often exceed 200 points.

In the triplexing system, three times the final input / output must be processed, and wiring and signal transmission problems arise in that these signals must be collected again into the selection circuit in order to configure the selection circuit.

The present invention is applied to the digital output device of the triple turbine control system to reduce the number of wiring between the control panel and to continue operation even if the main controller up to two failures to improve the reliability of the power plant control and to increase the utilization rate Can contribute.

On the other hand, Figure 6 shows an example of the control panel configuration of the triplex turbine control system to which the intelligent output device is applied.

In order to triple the unit controllers, which are multiplexed, are stored in one control panel 230, 240, and 250, and a main controller 231 for controlling and a protection controller 232 for protecting are installed therein.

The main controller receives external input / output data from the digital input / output rack 233 and the analog input / output rack 234, and arithmetic processing and delivers the result. The intelligent output device 235 is composed of the CPI 237 and the relay drive boards 238 and receives the output data in serial communication.

The signals of the intelligent output device and the input / output rack are connected to the outside through the terminal block board installed on the terminal block board 236.

The control panel of the same structure constitutes a triple control system, in which the intelligent digital output device can minimize the wiring between the control panels. In addition, this intelligent output device can eliminate the reliability bottleneck of the output selection circuit, and improve the reliability and utilization rate by allowing the main controller to continue operation normally even if two main controllers fail.

As described above, the present invention can expect the following effects.

First, it eliminates the part that lowers the reliability of the whole system by triplening the output selection circuit (many triple systems have one circuit for selecting the final output) in which the reliability bottleneck occurs in the triple system. It also prevents the system from shutting down due to the failure of a single component by triple the output devices such as relays as well as the controller.

Second, by configuring the selection circuit of the output necessary in the triple system using serial communication and intelligent output device, the wiring can be reduced, and the selection logic, which is generally adopted by software implementation of the selection logic, is 'three' In addition to the 2 'selection logic, the utilization of the plant is maximized by giving the flexibility to continue operation until a single controller is finally sound.

Third, if a failure occurs in the CPI of the main controller or output device due to the application of intelligent output device, the fault control system can be covered by covering the failure so that the failure can continue operation without affecting the control target. Can build effectively.

Fourth, by processing the synchronization signal or heartbeat signal (heartbeat signal) necessary in the output selection circuit of the triplex system by communication instead of a separate hardware signal line, it is possible to configure the output and the control circuit of the system more simply.

Claims (4)

Triple control main controller outputs control signal for control and monitoring of load side and independent of CPI (206, 207, 208) of output device using signal line (203, 204, 205) for digital output (200, 201, 202); The plurality of CPIs 206 to 208 connected to the main controllers 200, 201, and 202 through the signal lines 203, 204, and 205, respectively. An output device connected to exchange output information and configured to exchange data with the relay drive board 215 and other signal processing boards through the data / address buses 212, 213, and 214; Output device using serial communication of the triple control device, characterized in that consisting of. The relay driving board 215 receives data from the CPI via the data / address bus 216, and outputs only the output data corresponding to its own address through the signal line 230. And a logic element 217 which transmits a signal to the driving circuit 218 and shuts off or forcibly drives the output to the driving circuit when a failure is detected in response to a command from the CPI or on its own. Output of the furnace 218 is an output device using the serial communication of the triple control device, characterized in that configured to be connected to the relay terminal board through the signal line (219). 3. The relay terminal board of claim 2, wherein the relay-terminal block board receives relay drive signals 221, 222, and 223 from each output device using a connector to configure the hard-wired logic, respectively, and drives the relays 224, 225, and 226, respectively. Each relay has a logic circuit 227 that selects and outputs two out of three using two contacts. When two of the three relays operate normally, the load 229 is driven by the power supply 228. Output device using serial communication of the triple control device characterized in that the drive. A first step (S1) of checking the state of the upper main controller in a state in which each of the CPIs share data through communication with CPIs of the upper and multiplexed output devices; A second step of determining that the upper controller is sound when data is received from the main controller at regular intervals; A third step (S2) of checking the number of higher level controllers currently operating in a healthy state according to the determination of the second step and determining a method of selecting output data according to the result; A fourth step (S6) of selecting an output using two of three selection logics if all three upper controllers are sound as a result of the determination in the third step; A fifth step (S6) of indicating that a failure is detected by one host controller as a result of the third step (S3) and a final output is determined from the two healthy data; As a result of the determination in the third step, if two failures of the upper controllers are detected (S4), the controller displays the error (S4) and informs the driver whether to continue the operation (S5) or the preset driving condition (whether to continue to operate with one healthy main controller). According to a sixth step (S7) to determine the data of the sound controller as an output; Output device control method using serial communication of the triple control device characterized in that proceeds to.