JPH05159194A - Sensor system - Google Patents

Abstract

PURPOSE:To allow a sensor to detect its abnormality to take emergency measures such as an early replacement for the abnormality before causing the deterioration of products due to the abnormality. CONSTITUTION:A self check part provided on at least one of the flow meters 1a to 1c takes the measurement result of each flow meter 1a to 1c to be compared with the measurement result obtained through the measurement of the self flow meter. The self flow meter judges the state as normal at the time of the set relation, and judges it as abnormal at the time of not satisfying the relation to output an alarm signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor system in which a plurality of instruments are connected to a signal transmission line and used.

[0002]

2. Description of the Related Art In a sensor system used for controlling a plant and detecting various process amounts such as pressure and flow rate, a sensor is attached to a device to be measured and is obtained by each of these sensors. It is often the case that the various process quantities are transmitted to a supervisory controller installed in the center by analog signals of 4 to 20 mADC, and the supervisory controller controls and monitors the various process quantities.

Recently, by superimposing a digital signal on this analog signal, communication is performed between each sensor and the monitoring control device, and a sensor with a communication function and a process amount capable of changing the remote setting of each sensor are also available. Sensors with a communication function that can transmit digital signals have also been developed.

[0004]

By the way, in the conventional sensor used in such a sensor system,
Even if an error occurs in one of the sensors and the measurement error becomes large, the sensor does not have a function to detect the increase in error, so the manufacturing process using such a sensor system When the quality of the product is deteriorated, the sensor abnormality is often noticed for the first time.

Since such characteristics are the same even in a sensor with a communication function, it has been strongly desired to develop a sensor system capable of detecting an abnormality of the sensor before the quality of the product deteriorates.

In view of the above circumstances, the present invention allows the sensor itself to detect the abnormality of the sensor, thereby notifying the abnormality of the sensor before the deterioration of the quality of the product due to the abnormality of the sensor occurs and early It is an object of the present invention to provide a sensor system capable of performing a procedure such as replacement.

[0007]

In order to achieve the above object, a sensor system according to the present invention measures a physical quantity to be measured by a plurality of sensors attached to a measurement object side and monitors and controls the measurement result. In a sensor system that transmits to a device, it is provided in at least one of the sensors, captures the measurement result of each sensor, compares this measurement result with the measurement result obtained by the measurement operation of its own sensor, and sets these in advance. When the relationship is established, the sensor is determined to be normal, and when the relationship is not satisfied, the self-check unit is configured to determine that the sensor is abnormal.

[0008]

In the above structure, the measurement result of each sensor is taken in by the self-check section provided in at least one of the sensors, and the measurement result is compared with the measurement result obtained by the measurement operation of the self sensor. When these are in a preset relationship, the sensor is determined to be normal, and when the relationship is not satisfied, the sensor is determined to be abnormal and an alarm signal is output.

[0009]

1 is a block diagram showing an embodiment of a sensor system according to the present invention.

The sensor system shown in this figure comprises a plurality of flowmeters 1a to 1c serving as sensors, a central control monitoring device 2 provided on the center side, the central control monitoring device 2 and the flowmeters 1a to 1c. It is provided with the bus 3 to be connected, and the measurement result of the own flowmeter, for example, the flowmeter 1a, and another flowmeter,
For example, the central control of the flow rate detection signal obtained by the measurement operation is performed while comparing the measurement results of the flowmeters 1b and 1c and determining whether the measurement result of the own flowmeter 1a is good or not based on these comparison results. It transmits to the monitoring device 2, and the central control monitoring device 2 controls the state of the process whose flow rate is measured by each of the flowmeters 1a to 1c,
To monitor.

Each of the flow meters 1a to 1c outputs a flow rate measuring section for measuring the flow rate of the fluid flowing through the corresponding pipe 4a, 4b, 4c and a flow rate detection signal obtained by the measuring operation of the flow rate measuring section. A signal transmission unit that sends out to the central control and monitoring device 2 by sending it on the bus 3, and a flow measurement signal of another flow meter sent on the bus 3 by taking in the value of this flow measurement signal and A self-check unit for comparing the measurement result of the flow meter with the measurement result of the own flow meter to determine whether the measurement result of the own flow meter is correct, and the measurement result of the other flow meter sent to the bus 3 and the own flow meter. The flow rate detection signal obtained by the measurement operation is sent to the bus while judging whether or not the measurement result of the own flow meter is good based on these comparison results and the central control monitoring. Transmit to device 2.

In this case, the flow rate of the fluid flowing through each of the pipes 4a to 4c has the relationship shown by the following equation from the connection relation of the pipes 4a to 4c.

Q1 = Q2 + Q3 (1) where Q1: the flow rate of the fluid flowing through the pipe 4a Q2: the flow rate of the fluid flowing through the pipe 4b Q3: the flow rate of the fluid flowing through the pipe 4c and the self-check of each of the flow meters 1a-1c Part is Figure 2
When a flow rate detection signal is output from another flow meter as shown in the flow chart of FIG. 3, the flow rate detection signal is taken in (step ST1), and the flow rate detection signal value and the flow rate detection value obtained by the measurement operation of the own flow meter are obtained. Are compared with each other to check whether or not a preset relationship between them is satisfied, for example, the relational expression shown in the following equation is satisfied (step ST
2).

| Q1-Q2-Q3 | ≦ n (2) where n is a constant indicating an allowable range, and when the equation (2) is no longer satisfied, the self-check unit detects this and the self-flow meter It is determined that an abnormality has occurred in the vehicle, an alarm signal is generated, and this is transmitted to the central control monitoring device 2 via the bus 3 to be notified.

The central control and monitoring device 2 is provided with a CPU and the like for performing various processes, and each flow meter 1 is connected via the bus 3.
The flow rate detection signals output from a to 1c are taken in to monitor the flow rate of the fluid flowing through each of the pipes 4a to 4c,
Based on this monitoring result, various control signals are generated and supplied to each part of the process, and when an alarm signal is supplied via the bus 3, the control signal is taken in and any of the flowmeters 1a to 1c is fetched. An alarm indicating that an abnormality has occurred is generated and the operator is notified of this.

As described above, in this embodiment, the measurement results of other flow meters are compared with the measurement results of the own flow meter, and it is determined whether the measurement result of the own flow meter is good or not based on these comparison results. Since the flowmeters 1a to 1c can detect the abnormality in the flowmeters 1a to 1c themselves, the flowmeters 1a to 1c can be detected before the product quality deterioration due to the abnormality in the flowmeters 1a to 1c occurs. It is possible to notify the abnormality of 1c and perform an action such as early replacement.

Further, in this embodiment, each flow meter 1
Since a self-check of a to 1c is performed to check whether an abnormality has occurred in the own flow meter, a new cable or the like is laid between each flow meter 1a to 1c and the central control monitoring device 2. Each flow meter 1a without
It is possible to detect an abnormality of 1 to 1c, thereby minimizing the cost increase when providing this function.

Further, in the above-mentioned embodiment, it is determined whether or not an abnormality has occurred in the own flow meter based on the value of the flow rate detection signal output from each flow meter 1a-1c. Based on the value of each flow rate detection signal output from each of these flow meters 1a to 1c, operation information of an actuator (not shown) such as a valve, and information such as the set amount of these actuators, as shown in FIG. Calculate the allowable range for determining whether the meter is normal, compare the normal operating range obtained by this calculation operation with the value of the flow rate detection signal obtained by the measurement operation of the own flow meter, When the value of is out of the normal operation range, it may be determined that the own flow meter is abnormal and an alarm signal may be output.

Even in this case, the flowmeter itself can detect an abnormality in the flowmeters 1a to 1c while minimizing the cost increase as in the above-described embodiment, and thus the flowmeters 1a to 1c can be abnormal. Before the deterioration of the product quality due to the above occurs, it is possible to notify the abnormality of the flowmeters 1a to 1c and to perform the action such as the early replacement.

[0020]

As described above, according to the present invention, a sensor abnormality can be detected by the sensor itself, which allows the sensor abnormality to occur before the product quality deterioration due to the sensor abnormality occurs. The user can be informed of the fact that an early replacement or the like can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a sensor system according to the present invention.

FIG. 2 is a flowchart showing an operation example of the sensor system shown in FIG.

FIG. 3 is a schematic view showing another embodiment of the sensor system according to the present invention.

[Explanation of symbols]

 1a to 1c Flowmeter (sensor, self-check unit) 2 Central control monitoring device 3 Bus

Claims (1)

[Claims] 1. In a sensor system for measuring a physical quantity to be measured by a plurality of sensors attached to a measurement target side and transmitting the measurement result to a monitoring control device, at least one of the sensors is provided with When the measurement result of the sensor is taken in and the measurement result obtained by the measurement operation of the own sensor is compared and these have a preset relationship, it is determined that the sensor is normal, A sensor system comprising: a self-check unit that determines that the sensor is abnormal when the relationship is not satisfied.