Method for judging fault of heater on line

Abstract

The invention discloses a method for judging a fault of a heater on line, relates to the technical field of liquid crystal glass production, and is suitable for heating equipment in liquid crystal glass production. According to the method, the voltage U1 and the current I1 of the primary side of the transformer output by the power regulator are remotely read through PROFIBUS-DP communication, the ratio of U1 to I1 is calculated and compared with a preset reference value (normal fluctuation + / -30%), and an alarm is triggered when the ratio exceeds 130% or 70%. The system stores historical data in real time and generates a trend curve to assist tracing, a monitoring picture integrates load state display, dynamic alarm threshold adjustment and acousto-optic prompt functions, and supports rapid positioning of open circuit or short circuit fault types. According to the invention, remote monitoring is realized by using an existing industrial protocol and configuration software, hardware does not need to be newly added, the response speed is remarkably improved, poor products and low false alarm rate caused by abnormal heating are reduced, and the method can be expanded to various industrial heating scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal glass production, and in particular to a method for online judging heater failure. Background Art

[0002] During the liquid crystal glass production process, the DCS remote system controls hundreds of heaters in muffle furnaces, forming furnaces, and annealing furnaces. The operation of each heater becomes a key link in temperature control. Remote communication is used here to allow the DCS system to read the data of the underlying power regulator (such as U1, I1, etc.). Combined with multiple fault measurement data, the ratio of the transformer primary side voltage U1 and current I1, and the characteristic that U1 / I1 will immediately undergo sudden changes when the heater load is open-circuited or short-circuited, the system can immediately issue a remote alarm prompt when the U1 / I1 ratio suddenly changes, so that the operator can promptly identify the faulty heating load and deal with it in time, which will better stabilize the process temperature and reduce the occurrence of defects. Summary of the Invention

[0003] In order to solve the technical problems existing in the background technology, the present invention proposes a method for online judgment of heater failure.

[0004] The present invention proposes a method for online heater fault determination, comprising:

[0005] The DCS control system uses PROFIBUS-DP communication technology to remotely read the transformer primary side voltage U1 and current I1 output by the power regulator, calculate the U1 / I1 ratio, and trigger a heating load fault alarm when the ratio exceeds the preset normal fluctuation range.

[0006] Furthermore, the preset normal fluctuation range is 70% to 130% of the U1 / I1 ratio when the heating load operates normally, and a fault is determined when the range is exceeded.

[0007] Furthermore, the normal fluctuation range of the U1 / I1 ratio is determined based on experimental data or historical fault measurement data, and the alarm threshold is dynamically adjusted according to the heating load type.

[0008] Furthermore, the configuration program in the DCS control system implements the following steps:

[0009] Obtain the U1 and I1 values ​​output by the power regulator in real time through the PROFIBUS-DP communication module;

[0010] The U1 / I1 ratio is calculated in real time using the calculation module DIAV;

[0011] The comparison module DACA compares the real-time ratio with the preset alarm threshold and outputs a fault alarm signal.

[0012] Furthermore, the DCS control system stores historical data of the U1 / I1 ratio and displays it in the form of a historical trend graph to trace the failure time and status changes of the heating load.

[0013] Furthermore, a heating load failure alarm interface is set up in the remote monitoring screen, including the following elements:

[0014] The name of each heating load and the corresponding U1 / I1 ratio are displayed;

[0015] Adjustable parameters for alarm high limit setting value (130% of normal value) and alarm low limit setting value (70% of normal value);

[0016] Sound and light prompts and information recording function when the fault alarm is triggered.

[0017] Furthermore, the fault type is determined by the sudden change direction of the U1 / I1 ratio:

[0018] When the ratio suddenly rises and exceeds the high limit alarm value, it is determined to be a load open circuit fault;

[0019] When the ratio drops sharply and exceeds the lower alarm value, it is determined to be a load short circuit fault.

[0020] Furthermore, the method is applicable to fault monitoring of heating loads in muffle furnaces, forming furnaces or annealing furnaces used in the production of liquid crystal glass.

[0021] Furthermore, the alarm signal is linked to the temperature control logic of the DCS system, and when the alarm is triggered, a protective action is automatically executed or an operator is prompted to intervene.

[0022] Furthermore, the PROFIBUS-DP communication technology is replaced by other industrial Ethernet communication protocols, and the power regulator data reading method is compatible with ModbusTCP or OPCUA communication standards.

[0023] Beneficial effects of the present invention:

[0024] 1. Remote alarm for heating load failure can help operators respond quickly and promptly, improving the timeliness and speed of operators' handling of heating load anomalies, better controlling process temperature and reducing the occurrence of defects;

[0025] 2. The ratio of U1 / I1 is stored in the database and displayed in the form of historical trends, making it convenient for operators to view the historical status of each heating load;

[0026] 3. The heating load fault alarm value in the remote control screen can be modified accordingly according to the changes of each load heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A schematic diagram of a single heating load of the present invention;

[0028] Figure 2 This is a configuration block diagram of the heating load fault judgment and alarm program of the present invention;

[0029] Figure 3 Schematic diagram of the historical trend of the ratio U1 / I1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the heating load fault alarm setting screen of the present invention;

[0031] Figure 5 This is the heating electrical principle diagram of the present invention. DETAILED DESCRIPTION

[0032] Reference Figure 1-5 The present invention proposes a method for online heater fault determination, which includes the following contents when implementing the scheme:

[0033] 1. First, you need to build the system architecture, specifically:

[0034] S1.1. Configure the PROFIBUS-DP master module in the DCS control system to establish a communication connection with the on-site power regulator to ensure that the transformer primary side voltage U1 and current I1 signals output by the power regulator are transmitted to the DCS in real time via the DP bus.

[0035] S1.2. Connect the power regulator to the primary winding of the transformer, and the secondary winding of the transformer to the heating load (such as the heater in the muffle furnace, forming furnace or annealing furnace), forming a complete power supply circuit (see Figure 5 Electrical schematics).

[0036] 2. Secondly, data collection and processing are required, specifically:

[0037] S2.1. Create a PROFIBUS-DP communication subroutine in the DCS configuration software, define the power regulator device address and data mapping table, and periodically read U1 (instantaneous voltage value) and I1 (instantaneous current value).

[0038] S2.2. Calculate the U1 / I1 ratio in real time through DIAV (division calculation module) and store it in the DCS real-time database with associated timestamp.

[0039] S2.3. Use DACA (data comparison and alarm module) to set the reference value (the average value of U1 / I1 under normal working conditions) and the alarm threshold (the upper limit is the reference value × 130%, and the lower limit is the reference value × 70%).

[0040] 3. Furthermore, it is necessary to implement fault judgment logic, specifically:

[0041] S3.1. Write a conditional judgment statement in the configuration program. When the real-time U1 / I1 ratio is greater than the upper limit or less than the lower limit, the fault flag is triggered.

[0042] S3.2. Determine the fault type based on the ratio mutation direction:

[0043] If the ratio suddenly increases (for example, from 1.0 to 1.5), it is determined to be a load open circuit fault;

[0044] If the ratio drops suddenly (for example, from 1.0 to 0.5), it is determined to be a load short circuit fault.

[0045] S3.3. After the fault is triggered, the fault occurrence time, load number and ratio data are recorded through the SOE (Sequence of Events) function of the DCS.

[0046] 4. Furthermore, it is necessary to develop the monitoring interface and alarm function, specifically:

[0047] S4.1、Design remote monitoring screen (see Figure 4 ), which contains the following elements:

[0048] The list shows each heating load name and its current U1 / I1 ratio;

[0049] Editable input boxes are used to set the alarm high limit (DACA.PVHIALM.FL) and low limit (DACA.PVLOALM.FL);

[0050] The status indicator light (red / yellow / green) intuitively displays the load operating status;

[0051] S4.2. Integrated sound and light alarm module. When a fault occurs, an alarm window pops up on the monitoring screen accompanied by a buzzer prompt, and a push notification is sent to the operator's mobile terminal.

[0052] 5. Furthermore, historical data and trend analysis is required, specifically:

[0053] S5.1. Create a dedicated data table for the U1 / I1 ratio in the DCS historical database, set the storage period to 1 second, and retain the latest 90 days of historical records;

[0054] S5.2. Develop a historical trend query interface (see Figure 3 ), supports filtering data by time range and load number, and displays ratio fluctuations in the form of a curve to assist in fault tracing.

[0055] 6. Furthermore, dynamic parameter adjustment and extended application are required, specifically:

[0056] S6.1. Manually modify the baseline value and alarm threshold value through the monitoring screen according to the heating load change or process change. The DCS automatically saves the modification record to the audit trail log.

[0057] S6.2. Encapsulate this method into a standardized functional module, open the interface through the OPCUA protocol, support integration into other industrial control systems (such as PLC or SCADA systems), and expand its application to transformer load monitoring scenarios in industries such as metallurgy and chemical industry.

[0058] 7. Finally, linkage control and emergency response are required, specifically:

[0059] S7.1. Embed a fault response subroutine in the DCS control logic. When the same load fault is detected in three consecutive scan cycles, the following operations are automatically performed:

[0060] Cut off the output power of the corresponding power regulator;

[0061] Start the backup heating circuit (if configured);

[0062] Increase heater power in adjacent areas to compensate for temperature fluctuations;

[0063] S7.2. Generate a fault handling work order and push it to the maintenance terminal, instructing on-site personnel to bring designated spare parts (such as fuses and contactors) for maintenance.

[0064] Implementation effect verification

[0065] Through the simulated load open circuit / short circuit test, it is verified that the alarm trigger delay is less than 2 seconds and the false alarm rate is less than 0.1% (based on 1000 hours of continuous operation data).

[0066] In actual application, the operator response time was shortened to less than 5 minutes, and the product defect rate due to heating failure decreased by 85%.

[0067] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for online judgment of heater failure, characterized in that: include: The DCS control system uses PROFIBUS-DP communication technology to remotely read the transformer primary side voltage U1 and current I1 output by the power regulator, calculate the U1 / I1 ratio, and trigger a heating load fault alarm when the ratio exceeds the preset normal fluctuation range.

2. The method for online heater failure determination according to claim 1, characterized in that: The preset normal fluctuation range is 70% to 130% of the U1 / I1 ratio when the heating load is working normally. If it exceeds this range, it is determined to be a fault.

3. The method for online heater failure determination according to claim 1 or 2, characterized in that: The normal fluctuation range of the U1 / I1 ratio is determined based on experimental data or historical fault measurement data, and the alarm threshold is dynamically adjusted according to the heating load type.

4. The method for online heater failure determination according to claim 1, characterized in that: The configuration program in the DCS control system implements the following steps: Obtain the U1 and I1 values ​​output by the power regulator in real time through the PROFIBUS-DP communication module; The U1 / I1 ratio is calculated in real time using the calculation module DIAV; The comparison module DACA compares the real-time ratio with the preset alarm threshold and outputs a fault alarm signal.

5. The method for online heater failure determination according to claim 1, characterized in that: The DCS control system stores historical data of the U1 / I1 ratio and displays it in the form of a historical trend chart to trace the failure time and status changes of the heating load.

6. The method for online heater failure determination according to claim 1, characterized in that: Set up the heating load failure alarm interface in the remote monitoring screen, including the following elements: The name of each heating load and the corresponding U1 / I1 ratio are displayed; Adjustable parameters for alarm high limit setting value and alarm low limit setting value; Sound and light prompts and information recording function when the fault alarm is triggered.

7. The method for online heater failure determination according to claim 1, characterized in that: Determine the fault type by the sudden change direction of the U1 / I1 ratio: When the ratio suddenly rises and exceeds the high limit alarm value, it is determined to be a load open circuit fault; When the ratio drops sharply and exceeds the lower alarm value, it is determined to be a load short circuit fault.

8. The method for online heater failure determination according to claim 1, characterized in that: Suitable for fault monitoring of heating loads in muffle furnaces, forming furnaces or annealing furnaces used in LCD glass production.

9. The method for online heater failure determination according to claim 1, characterized in that: The alarm signal is linked to the temperature control logic of the DCS system. When the alarm is triggered, the protection action is automatically executed or the operator is prompted to intervene.

10. The method for online heater failure determination according to claim 1, characterized in that: The PROFIBUS-DP communication technology is replaced by other industrial Ethernet communication protocols, and the power regulator data reading method is compatible with ModbusTCP or OPCUA communication standards.

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