JPH035614A - Control of incinerator by doubled sensor - Google Patents

Abstract

PURPOSE:To improve reliability by providing a plurality of monitoring sensors with the same purpose, automatically changing over to a normal sensor when the other sensor is apparently abnormal, warning and letting an operator select the normal sensor when a deviation between both the sensors is above a set value. CONSTITUTION:Two sensors 8 are provided for the same purpose and an input is given to a low order computer 5. A computational processing is performed in a given procedure and a result is fed to a host computer (high order computer) 3. That is, the computer 5 obtains a deviation between the data of the two sensors 8 and compares the deviation with a set value. When the deviation exceeds the set value and the sensor 3 that is not selected is not abnormal, an excessive deviation alarm is emitted, urging sensor changeover. When the selected sensor 8 is apparently abnormal and the other sensor is not abnormal, the sensors are automat-. cally changed over from one to the other. This construction can improve reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a redundant control method for improving the reliability of sensors applied to garbage incinerators.

[Prior Art] Various sensors are used in waste incinerators to detect exhaust gas temperature, furnace internal pressure, temperature, boiler drum water level attached to the furnace, turbine inlet pressure, and the like. In this regard, a duplication method in which two sensors are used for different purposes is often used. Another commonly adopted method is a winner-take-all method in which three sensors are installed at the same location for the same purpose, and the majority rule is used to capture correct information.

[Problems to be Solved by the Invention] However, the prior art duplication method using two sensors used for different purposes does not meet the objective of improving the reliability of information from the sensors themselves. Moreover, the three-way method increases costs.

Therefore, an object of the present invention is to provide a simple and reliable method for controlling sensor redundancy.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, two sensors are installed in the same place for the same purpose, and one sensor is prevented from short-circuiting, disconnection, poor contact, etc. In the event of an obvious abnormality, the system automatically switches to the other normal sensor to capture information, and if the deviation of information (numeric data) from both sensors exceeds a preset value, an alarm is generated. The reliability of the information from the sensor is ensured by having the operator select the normal sensor and switching over to take in normal information.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the simplest configuration of a control and monitoring device for a waste incineration plant. The analog value and ON or OFF digital value input from the sensor 8 are converted into digital values of the required voltage level by the input processing unit 7, and sent to the control calculation unit 6, where they are used as data for calculation. The result is converted into a required voltage, current analogue or voltage, and on-off digital output in the output processing section, and control is realized by operating the operating end 8. This input and output data is also sent to the higher-level computer 3 via the communication bus 4, so that the higher-level computer can display and print out the occurrence of an alarm. In addition, the upper side can change the load of the control calculation software of the control calculation section on the lower side.
This is the so-called man-machine interface part.

FIG. 2 is a flowchart showing an example of the calculation method according to the present invention, and has the functions described below.

1) This control computer stores sensor selection data in a non-volatile memory (11).

2) Unless the deviation of the data from the two sensors exceeds the preset value (13) and the unselected sensor is abnormal (obvious such as short circuit or disconnection) (
14) Generate an excessive deviation alarm (15) to prompt the operator to switch the sensor.

3) If an excessive deviation alarm occurs, the sensor can be switched at the discretion of the operator (16°17.18.19
).

4) If the selected sensor is abnormal and the other is not, the sensor will be automatically switched (12°21.28)
.

5) If both sensors become abnormal, hold the data immediately before the abnormality of the selected sensor.
2, 21, 22, 23), once the sensor abnormality is restored,
Select the sensor that was automatically restored (24, 25,
26.27).

6) If the data is held, the data used for the control calculation is the held data; if the data is not held, the data from the selected sensor is used (29, 30° 31).

[Effects of the Invention] According to the present invention, abnormalities in detected data can be detected early, and normal data can always be detected, and the reliability of detected data is increased, which increases the reliability of alarms. There is also no fear that erroneous control will be performed.

[Brief explanation of drawings]

FIG. 1 is an overall diagram of a control device according to an embodiment of the present invention. FIG. 2 is a flowchart showing the calculation method according to the present invention. 3... Upper arithmetic processing unit (computer), 5...
Lower arithmetic processing unit (computer), 8...sensors, operating devices, etc.

Claims (1)

[Claims] Two sensors with the same purpose are installed to control the waste incinerator and monitor its status, and when one sensor has an obvious abnormality such as a short circuit or disconnection, it automatically switches to the other normal sensor. When information is imported and the deviation of the information (numeric data) from both sensors exceeds a preset value, an alarm is generated and the operator is asked to select and switch to the normal sensor. A control method for ensuring reliability of information from a sensor, characterized by performing arithmetic processing to capture normal information.