Gas furnace shutdown interlock industrial automation acquisition control simulation device

Abstract

The utility model provides a kind of gas furnace shutdown interlock industrial automation acquisition control simulation device, including PLC, PLC analog quantity extension unit, touch screen, 24V DC power supply, steam pressure signal generator, balancer water level meter signal generator.The simulation device of the utility model has stronger fault injection capability, optimized control logic debugging, better universality and compatibility.

Description

Technical Field

[0001] This utility model belongs to the field of industrial automation data acquisition and control technology for gas-fired boiler shutdown interlock, and in particular relates to a simulation device for industrial automation data acquisition and control of gas-fired boiler shutdown interlock. Background Technology

[0002] Gas-fired boilers use natural gas as fuel. If abnormal combustion or gas leaks occur, and the boiler is not shut down promptly, it could lead to serious safety accidents such as explosions and fires, causing casualties and property damage. Shutdown interlock technology can quickly cut off the gas supply and stop related operating equipment in the event of a dangerous situation, minimizing safety risks.

[0003] Incomplete combustion of gas in the furnace produces toxic and harmful gases such as carbon monoxide, posing a threat to human health and the environment. A shutdown interlock can promptly shut down the furnace upon detecting combustion abnormalities. To enable maintenance and technical personnel to better understand and troubleshoot gas furnace shutdown interlock faults and conduct maintenance training to meet the technological demands of electrical development, a simulation device is being developed. This device simulates the operating conditions of a gas furnace under various possible fault conditions, such as gas leakage, overheating, and overpressure. The aim is to verify whether the shutdown interlock device can be triggered promptly and accurately, ensuring the safety control requirements for personnel and equipment are met when similar problems occur in real-world scenarios. Utility Model Content

[0004] This invention aims to address the threat to the health and environment posed by maintenance personnel and technicians during the troubleshooting and maintenance training of gas furnace shutdown interlock systems. It provides an industrial automation data acquisition and control simulation device for gas furnace shutdown interlock systems, offering operators a realistic simulation environment to familiarize them with the operation procedures and emergency response methods of the gas furnace shutdown interlock system, enabling them to react correctly and quickly when encountering problems in actual work.

[0005] To achieve the above-mentioned utility model objectives, this utility model provides an industrial automation data acquisition and control simulation device for gas-fired boiler shutdown interlock, including a PLC, a PLC analog expansion unit, a touch screen, a 24V DC power supply, a steam pressure signal generator, and a balancer water level gauge signal generator.

[0006] The main power switch is connected to a 24V DC power supply, which supplies power to the circuit through DC power switch QF3; the PLC is connected to the power supply through PLC power switch QF1.

[0007] PLC input terminals:

[0008] I0.0 connects to the system start button SB1; I0.2 connects to the electrical contact interlock switch QF4; I0.3 connects to the electrode interlock switch QF5; I1.0 connects to the system stop button SB2; I1.1 connects to the electrical contact low water level NO1; I1.2 connects to the electrical contact extremely low water level NO2; I1.3 connects to the spare NO3; I1.4 connects to the electrical contact high water level signal.

[0009] PLC output terminals:

[0010] Q0.0 connects to the system operation indicator light; Q0.1 connects to the system stop indicator light; Q0.2 connects to the high water level alarm light via a relay; Q0.3 connects to the high water level alarm light of the balancer; Q0.4 connects to the low water level alarm light via a relay; Q0.5 connects to the low water level alarm light of the balancer; Q0.6 connects to the low water level shutdown signal light via a relay; Q0.7 connects to the low water level shutdown signal light of the electrode rod via a relay; Q1.0 connects to the high boiler pressure signal light; Q1.1 connects to the buzzer via a relay.

[0011] The PLC analog expansion unit includes analog expansion unit one and analog expansion unit two;

[0012] The analog signal expansion unit is used to receive signals from the steam pressure signal generator and is connected via the RA, A+, and A- interfaces.

[0013] Analog expansion unit 2 is used to receive signals from the balancer level gauge signal generator and is connected via RA, A+, and A- interfaces;

[0014] The PLC is used to determine whether the input signal exceeds the set threshold based on the input signal at the input terminal and outputs a signal through the alarm light or signal light connected to the output terminal.

[0015] The PLC is connected to a touch screen, which is used to monitor the system's operating status and set parameters.

[0016] The simulation device of this invention has a stronger fault injection capability: it can flexibly and accurately inject various faults during the simulation process, observe the shutdown interlock system's response in real time, and facilitate researchers to comprehensively evaluate the system's reliability in dealing with various faults. In contrast, existing fault injection methods are limited and difficult to simulate complex fault scenarios.

[0017] Optimized control logic debugging: With the help of simulation control software and an intuitive human-machine interface, researchers can easily adjust control logic parameters and repeatedly test the effects of different logic combinations. Compared with traditional debugging on actual equipment, this method is more efficient, lower in cost, and does not affect production operations, significantly improving the speed and effectiveness of control logic optimization.

[0018] Significantly improved training effectiveness: Providing operators and maintenance personnel with a highly realistic simulation training environment that mimics various situations that may be encountered in actual work allows them to accumulate rich experience in a safe environment. Compared to traditional training methods, this hands-on training enables personnel to master operating skills and troubleshooting methods more quickly, significantly improving training effectiveness.

[0019] Improved versatility and compatibility: This utility model's simulation device features a flexible design. Through modular design and parameter adjustment, it can adapt to the research and testing of shutdown interlock systems for different types and specifications of gas-fired boilers. Existing technologies are often limited to specific models or types of gas-fired boilers, resulting in poor versatility. This utility model greatly expands its applicability and promotes the technological development of the entire gas-fired boiler industry. Attached Figure Description

[0020] Figure 1 This is a functional block diagram of the industrial automation data acquisition and control simulation device for gas furnace shutdown interlock of this utility model;

[0021] Figure 2 This is the electrical schematic diagram of the industrial automation data acquisition and control simulation device for gas furnace shutdown interlock of this utility model;

[0022] The components include: 1. PLC; 2. PLC analog expansion unit; 3. 24V DC power supply; 4. Steam pressure signal generator; 5. Balancer water level gauge signal generator; 6. Touch screen. Detailed Implementation

[0023] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed account of the industrial automation data acquisition and control simulation device for gas-fired furnace shutdown interlocking.

[0024] Reference Figure 1 The industrial automation data acquisition and control simulation device for gas-fired boiler shutdown interlock includes a PLC1, a PLC analog expansion unit2, a 24V DC power supply3, a steam pressure signal generator4, a balancer level gauge signal generator5, and a touch screen6.

[0025] PLC1 is a Siemens S7-200 series programmable logic controller (PLC) launched by Siemens, which has the following advantages:

[0026] (1) High cost-performance ratio and high performance. (2) Powerful functions and rich instructions. (3) High reliability, ensuring stable system operation. (4) Low programming difficulty, shortening the development cycle. (5) Good scalability, allowing flexible expansion of system functions and scale according to actual needs. (6) Strong communication capability, supporting multiple communication protocols such as PPI, MPI, and Profibus-DP, facilitating communication with other devices such as host computers and touch screens to achieve system integration and monitoring.

[0027] Touchscreen 2 is a Kunlun Tongtai touchscreen, which has the following advantages:

[0028] (1) Stable performance, adaptable to complex industrial environments. (2) Good display effect and easy operation. (3) Equipped with multiple communication interfaces to realize data transmission and sharing, facilitating integration with industrial equipment such as PLCs and frequency converters to build a complete automated control system. (4) Powerful configuration software, reducing development costs and difficulty.

[0029] The steam pressure signal generator 4 and the balancer level gauge signal generator 5 both use 4-20mA current signal analog generators, which have the following advantages:

[0030] (1) High precision, meeting the requirements of applications with high measurement and control accuracy. (2) Strong stability, less affected by environmental temperature, humidity and other factors. (3) Good compatibility, easy to integrate into existing industrial control systems. (4) Easy to adjust, allowing users to flexibly change the output signal size according to actual needs.

[0031] The PLC is connected to the touch screen, switches, buttons, DC power supply, and signal generator. The 24V DC power supply 3 is connected to the main power switch QF1, PLC, indicator lights, and relays. The PLC communicates with the touch screen. The PLC analog expansion unit is connected to the 4-20mA signal generator.

[0032] Through the above connections, the PLC is input with switch signals via buttons SB1 and SB2, circuit breakers QF4 and QF5, contacts NO1, NO2, and NO3 of the liquid level monitor, and internal variables of the touch screen. The PLC performs internal logic operations to simulate the operation of the boiler system.

[0033] As the core component, PLC1 receives switch signals from buttons SB1 and SB2, circuit breakers QF4 and QF5, and contacts NO1, NO2, and NO3 of the level monitor, as well as from the internal variables of the touchscreen. Through internal logic operations, it controls the output signals of the PLC to display relevant indicator lights and the functions on the touchscreen screen. Circuit breaker QF1 is connected to the L and N terminals of the PLC to provide power.

[0034] Figure 2 This is the electrical schematic diagram of this device. The following is an analysis of the schematic diagram.

[0035] Power supply section

[0036] (1) Main power supply: The power input of the entire system is controlled by the main power switch QF2.

[0037] (2) 24V DC power supply: 24V DC power supply is provided to some circuits of the system via DC power switch QF3.

[0038] (3) PLC power supply: The PLC-related circuits are powered by the PLC power switch QF1.

[0039] The core unit of the PLC is used to determine whether the input signal exceeds the set threshold based on the input signal from the input terminal and output the alarm light or signal light connected to the output terminal.

[0040] Input (I) terminal

[0041] I0.0 is connected to the system start button SB1. When SB1 is pressed, the system start signal is transmitted to the PLC.

[0042] I0.2 connects to electrical contact interlock switch QF4, used to monitor the interlock status of relevant electrical contacts.

[0043] I0.3 connects to electrode interlock switch QF5 to monitor the electrode interlock status.

[0044] Connect I1.0 to the system stop button SB2. Pressing SB2 sends a system stop signal to the PLC.

[0045] I1.1-I1.4 are respectively connected to the electrical contact low water level (NO1), electrical contact extremely low water level (NO2), standby (NO3), and electrical contact high water level signals for water level status monitoring.

[0046] Output (Q)

[0047] Q0.0 connects to the system running indicator light, which illuminates when the system is running.

[0048] Q0.1 Connects to the system stop indicator light, which illuminates when the system stops.

[0049] Q0.2-Q0.6 are respectively connected to the high water level alarm light (via relay), the high water level alarm light of the balancer, the low water level alarm light (via relay), the low water level alarm light of the balancer, and the low water level shutdown signal light (via relay).

[0050] Q0.7 is connected to the low water level shutdown signal light on the electrode rod via a relay.

[0051] Q1.0 connects to the boiler pressure over-high indicator light.

[0052] Q1.1 Connect a buzzer via a relay for alarm sound.

[0053] Signal generation and extension section

[0054] Analog expansion unit: There are two analog expansion units: Analog Expansion Unit 1 and Analog Expansion Unit 2.

[0055] The analog signal extension unit receives signals from the steam pressure signal generator and connects via the RA, A+, and A- interfaces to monitor steam pressure.

[0056] The analog signal extension unit 2 receives the signal from the balancer level gauge signal generator and connects through the RA, A+, and A- interfaces to monitor the balancer level.

[0057] Human-computer interaction section

[0058] Touch screen: can be used to monitor system operating status, set parameters, and interact with PLC to achieve visual control.

[0059] Simulated Example:

[0060] Simulated High Water Level: Under the simulated operating environment of this patented device, the boiler, controlled by a Siemens S7-200 PLC, is brought to a stable operating state after startup. During this time, the operator must closely monitor the changes in the electrical contact water level gauge readings and the indicator light status displayed on the Kunlun Tongtai touchscreen. When the simulated boiler water level reaches the +50 position on the electrical contact water level gauge, the corresponding indicator light turns red. Simultaneously, a buzzer connected to the PLC and controlled by programmed logic sounds an alarm. Based on the device's preset interlocking logic and judgment criteria, the high water level test is deemed normal. Afterwards, the simulated return water operation is controlled by the PLC to return the boiler water to the normal level, ending the simulated high water level test.

[0061] Simulated Low Water Level at Electrical Contact Points: To conduct this simulation experiment, first disconnect the electrode rod power switch using the corresponding circuit breaker QF5 (electrode rod power switch) on the operating device. Then, under the control logic of the PLC, observe the value of the electrical contact water level gauge and the changes in the indicator light on the Kunlun Tongtai touchscreen during the simulated boiler water return process. When the simulated boiler water level reaches the -50 position on the electrical contact water level gauge, the indicator light turns red, the buzzer sounds an alarm, and an alarm sound is emitted. The simulated boiler continues to return water. When the water level reaches the -75 to -100 range on the electrical contact water level gauge (the boiler will shut down if the water level is below -75), according to the interlock shutdown logic set by the device, the low water level experiment is determined to be normal. Subsequently, the simulated water return operation is controlled again by the PLC to return the boiler water to the normal level, ending the simulated low water level experiment.

[0062] Simulated Low Electrode Rod Water Level: When conducting this electrode rod interlocking experiment, first control the corresponding power-off contact interlock via software programming or operation, then perform the electrode rod experiment. On the intelligent liquid level control panel (operated via the Kunlun Tongtai touchscreen), press the drain button twice. At this time, all indicator lights on the electrical contact water level gauge will turn red and an alarm sound will be emitted. Press the corresponding mute button on the touchscreen to silence the alarm. Simulate boiler water return. When the water level drops below -75, the boiler will shut down under the PLC's preset interlocking control, indicating the low boiler electrode rod water level experiment is normal. Finally, control the simulated water return to bring the boiler water back to the normal level via the PLC, ending the simulated low boiler water level experiment.

[0063] Simulated high steam pressure: The normal setting in this patented simulation device is that the boiler steam pressure exceeds 1.2 MPa, triggering a shutdown. In the simulation panel operating system (based on the Kunlun Tongtai touchscreen interface), make the following settings: Login password 9878, select engineer mode; normal setting value is 0.80 MPa, shutdown deviation 0.40 MPa. Modify the shutdown deviation to 0.00 MPa via the touchscreen. Adjust the setting value according to the actual steam pressure of the simulated boiler (simulated by a 4-20mA current signal generator and pressure sensor, and transmitted to the PLC). The set value must be lower than the actual steam pressure. After clicking the confirmation button on the touchscreen, the simulated boiler should shut down and automatically restart under the logic control of the PLC. After completing the test, restore the setting value and shutdown deviation value to the normal setting value (setting value 0.80 MPa, shutdown deviation 0.40 MPa) via the touchscreen, click confirmation and exit, and delete the login password.

Claims

1. A gas furnace shutdown interlock industrial automation acquisition control simulation device, characterized in that: Includes PLC (1), PLC analog expansion unit (2), touch screen (6), 24V DC power supply (3), steam pressure signal generator (4), balancer water level gauge signal generator (5); The main power switch is connected to a 24V DC power supply (3), and the 24V DC power supply (3) supplies power to the circuit through the DC power switch QF3; the PLC (1) is connected to the power supply through the PLC power switch QF1; PLC(1) input terminals: I0.0 connects to the system start button SB1; I0.2 connects to the electrical contact interlock switch QF4; I0.3 connects to the electrode interlock switch QF5; I1.0 connects to the system stop button SB2; I1.1 connects to the electrical contact low water level NO1; I1.2 connects to the electrical contact extremely low water level NO2; I1.3 connects to the spare NO3; I1.4 connects to the electrical contact high water level signal. PLC(1) output terminals: Q0.0 connects to the system operation indicator light; Q0.1 connects to the system stop indicator light; Q0.2 connects to the high water level alarm light via a relay; Q0.3 connects to the high water level alarm light of the balancer; Q0.4 connects to the low water level alarm light via a relay; Q0.5 connects to the low water level alarm light of the balancer; Q0.6 connects to the low water level shutdown signal light via a relay; Q0.7 connects to the low water level shutdown signal light of the electrode rod via a relay; Q1.0 connects to the high boiler pressure signal light; Q1.1 connects to the buzzer via a relay. The PLC analog expansion unit (2) includes analog expansion unit one and analog expansion unit two; The analog signal extension unit is used to receive the signal from the steam pressure signal generator (4) and is connected through the RA, A+, and A- interfaces; The analog quantity expansion unit 2 is used to receive the signal from the balancer water level gauge signal generator (5), and is connected through the RA, A+, and A- interfaces; The PLC(1) is used to determine whether the input signal from the input terminal exceeds the set threshold and output the alarm light or signal light connected to the output terminal; The PLC (1) is connected to the touch screen (6), which is used to monitor the system's operating status and set parameters.

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