JP2021174099A - Intrinsically safe explosion-proof type detection system - Google Patents

Abstract

To provide an intrinsically safe explosion-proof type detection system capable of reducing management cost of power supply units.SOLUTION: An intrinsically safe explosion-proof type detection system 100 comprises: a plurality of detectors 10 that detect whether predetermined abnormalities are detected and that include input/output units for outputting detection results as digital signals to signal converters 72 and for inputting and outputting the digital signals to and from the signal converters 72; the signal converters 72 for relaying signal transmission and reception between the detectors 10 and a host system 80; power supply units 74 for supplying electric power to the detectors 10; cable units 90 that include a plurality of signal transmission lines provided so as to connect between the signal converters 72 and the input/output units and supply electric power from the power supply units 74 to the detectors 10; and wireless transmission/reception units 76 for transmitting and receiving signals by wireless communication between the host system 80 and the signal converters 72.SELECTED DRAWING: Figure 1

Description

The present invention relates to an intrinsically safe explosion-proof detection system.

Conventionally, a wireless device provided with a sensor has been known as a measuring instrument (Patent Documents 1 and 2).

JP-A-2019-921116 JP-A-2019-90761

Regarding detectors installed in dangerous places filled with flammable gas, etc., there are cases where multiple detectors are installed in the monitoring area. Since it is provided, the cost for battery replacement increases.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an intrinsically safe explosion-proof detection system capable of reducing the management cost of the power supply unit.

In order to achieve the above object, the intrinsically safe explosion-proof detection system according to the present invention monitors environmental information or determines whether or not a predetermined abnormality has been detected based on the sensor information detected by the sensor. A plurality of detectors including a detection unit and an input / output unit that outputs a monitoring result or a determination result by the detection unit to a signal converter as a digital signal and exchanges a digital signal with the signal converter, and the plurality of units. A signal converter that relays the transmission and reception of signals between each of the detectors and the host device, a power supply unit that supplies power to each of the plurality of detectors, and the signal converter and the plurality of detectors. A signal transmission line for transmitting the digital signal provided so as to connect to each of the input / output units of the detector is included, and power is supplied to the detector from the power supply unit. It is configured to include a transmission cable unit for performing signals and a wireless transmission / reception unit for transmitting and receiving signals between the host device and the signal converter by wireless communication.

According to the intrinsically safe explosion-proof detection system, which is one aspect of the present invention, the effect that the management cost of the power supply unit can be reduced can be obtained.

It is a block diagram which shows the structure of the intrinsically safe explosion-proof detection system which concerns on 1st Embodiment of this invention. It is the schematic which shows the structure of the cable part which concerns on 1st Embodiment of this invention. It is a graph which shows the change of the current in the transmission system using Manchester coded bus feeding. It is a figure for demonstrating the transmission system using the balanced differential signal transmission. It is a graph which shows the change of voltage in the transmission system using the balanced differential signal transmission. It is an image diagram when the detector is connected in a tree. It is a graph which shows the change of the voltage in the transmission system using Manchester coded bus power supply. It is a graph which shows the change of voltage in the transmission system using high frequency voltage modulation. It is a block diagram which shows the structure of the detector which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the arithmetic processing part of the detector which concerns on 1st Embodiment of this invention. It is a figure which shows the data structure of the transmission signal from a detector. It is a sequence diagram which shows the exchange of a signal between a superordinate system of an intrinsically safe explosion-proof detection system, a signal converter, and a detector at a normal time. It is a sequence diagram which shows the exchange of a signal between a superordinate system of an intrinsically safe explosion-proof detection system at the time of an abnormality, a signal converter and a detector. (A) A graph showing a change in the current of a single fire signal, (B) a graph showing a change in the current of a single fire signal, and (C) a graph showing a change in the current of a signal obtained by superimposing two fire signals. be. It is a sequence diagram which shows the signal exchange between the superordinate system of an intrinsically safe explosion-proof detection system, a signal converter, and a detector when a fire signal is output at the same time. It is an image diagram at the time of disconnection or short circuit of a cable part. It is a block diagram which shows the structure of the intrinsically safe explosion-proof detection system which concerns on 2nd Embodiment of this invention. It is an image diagram at the time of disconnection or short circuit of a cable part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Outline of Embodiment of the present invention>
An embodiment of the present invention is a network of an intrinsically safe explosion-proof detection system that detects a fire or an abnormal temperature at a dangerous place (combustible gas vapor place, flammable dust place) and transmits the information to a higher-level system by wireless communication. It is related to the configuration.

In addition, most of each detector operates in sleep mode (current consumption: about 400 nA), and environmental data of the installation location (temperature, vibration, pressure, gas concentration, sound, impact, rotation speed, liquid level, etc.) The running mode (current consumption: several μA to several 100 μA) is set only when the above is acquired.

Although the time required to acquire the above environmental data varies depending on the detector, it is about 60 to 90 [s] each time, and even if it is performed about 6 to 8 times a day, the running mode per day is 5 minutes. Most of the time is spent in sleep mode.

Switching to the running mode can be performed by using the built-in timer of the microcomputer of each detector or by interrupting by polling from the signal transmitter / receiver. After acquiring the environmental data and transmitting it to the signal transmitter / receiver, Re-transition to sleep mode.

For example, in the above-mentioned microcomputer, the above-mentioned operation can be executed with extremely low power consumption by stopping the CPU, the flash, and most of the peripheral functions and operating only the clock.

It is also effective to provide a progressive circuit or the like in each detector and control the start of operation from the signal transmitter / receiver. As a result, the number of detectors connected to the cable unit as viewed from the power supply unit (battery unit) is one, and only the operating current of the detector is the current consumption.

For signal transmission between each detector and signal transmitter / receiver, for example, LVDS (Low voltage differential signaling) or MBP with reduced current / voltage modulation is used for the physical layer, and a unique protocol with reduced data volume is used. As a result, the current consumption related to the transmission is also reduced.

Furthermore, for signal transmission of the lower wireless transmitter / receiver, for example, LPWA (Low Power Wide Area, LoRaWAN or Sigfox) is used for the physical layer, and by reducing the amount of data as a unique protocol, the current consumption related to the transmission is also reduced. Reduce.

Here, an example of the monitoring cycle or the detection cycle by the detector is listed below. As shown below, depending on the information to be collected, the detection cycle according to the type of detector may be shortened in the pre-alarm judgment, or conversely, if the normal state continues for a long period of time, it may be possible to shift to a longer detection cycle. Take measures such as Therefore, the network cycle is determined by the detector with the longest detection cycle.

When the type of detection content is flame detection, the high-speed detection type has a detection cycle of 50 ms. In this case, the flame is determined in 3s and restored in 30s. In the standard type, the detection cycle is 500 ms. In this case, when a flame is detected for 1 to 2 consecutive cycles, the pre-alarm shifts to the pre-alarm, and then shifts to the same detection cycle as the high-speed detection type.

When the detector 10 also detects the position of the flame, the position is determined in 10 s after the above flame determination.

Further, when the type of detection content is abnormality detection for flame, abnormal temperature detection (high temperature type), and the temperature in the range of 240 to 480 ° C. is monitored, the detection cycle is 60 s. If the monitored temperature is equal to or higher than the set value, it is judged to be a high temperature object, and if it is judged to be a high temperature object for 1 to 2 cycles, it shifts to a pre-alarm, for example, it is judged to be a high temperature object for 10 minutes in a row. If so, it is determined that the temperature is abnormal.

When the type of detection content is flame abnormality detection, abnormal temperature detection (low temperature type), and the temperature in the range of 80 to 200 ° C. is monitored, the detection cycle is 1 h. If the monitored temperature is equal to or higher than the set value, it is judged to be an abnormal temperature object, and if it is judged to be an abnormal temperature object for 1 to 2 consecutive cycles, it shifts to a pre-alarm. If it is determined to be present, it is determined that the temperature is abnormal.

Further, when the type of detection content is temperature detection, temperature monitoring (high temperature type) is performed, and the temperature in the range of 240 to 480 ° C. is monitored, the monitoring cycle is 60 s. Further, when the type of detection content is temperature monitoring (low temperature type) and the temperature in the range of 80 to 200 ° C. is monitored, the monitoring cycle is 1h.

When the type of detection content is gas leak detection, the detection cycle is 50 ms as in the high-speed flame detection type, or 500 ms as in the standard type.

Further, when the type of detection content is liquid leakage detection, the detection cycle is 1h. When the monitored resistance value is continuously below the threshold value for 5 hours, the process shifts to the pre-alarm, and when it is determined that the resistance value monitored continuously for 10 hours to 24 hours is below the threshold value, it is determined that a liquid leak has been detected. ..

When the type of detection content is impact detection, the detection cycle is 1 ms. When the monitored acceleration is continuously equal to or higher than the threshold value for 5 ms, the process shifts to the pre-alarm, and when it is determined that the monitored acceleration for 10 ms to 24 ms is continuously equal to or higher than the threshold value, it is determined that an impact has been detected.

[First Embodiment]
<System configuration>
Hereinafter, the intrinsically safe explosion-proof detection system according to the first embodiment of the present invention will be described.

As shown in FIG. 1, the intrinsically safe explosion-proof detection system 100 according to the first embodiment of the present invention includes a plurality of detectors 10, a barrier 70, a signal converter 72, a power supply unit 74, and a radio. It includes a transmitter / receiver 76 and a host system 80. A plurality of sets including a plurality of detectors 10, a barrier 70, a signal converter 72, a power supply unit 74, and a wireless transmitter / receiver 76 are provided.

The signal converter 72 and the plurality of detectors 10 are connected by a cable unit 90.

The host system 80 includes any one or more of a host computer 82, a DCS / PLC 84, and a control panel 86, and a wireless transmitter / receiver 88. The host system 80 and the signal converter 72 are connected via wireless communication. The detector 10, the barrier 70, the signal converter 72, the power supply unit 74, and the wireless transmitter / receiver 76 are installed at dangerous locations, and the host system 80 is installed at non-dangerous locations.

The signal converter 72 relays and converts digital signals between the detector 10 and the wireless transmitter / receiver 76. The power supply unit 74 supplies electric power to each detector 10 via the cable unit 90. The power supply unit 74 is composed of a primary battery or a secondary battery. The wireless transmitter / receiver 76 transmits / receives signals between the host system 80 and the signal converter 72 by wireless communication.

A plurality of detectors 10 installed in a dangerous place are connected to a cable portion 90 via a T-branch connector 90C, and are connected to a non-dangerous place via a barrier 70, a signal converter 72, and a wireless transmitter / receiver 76. Half-duplex communication is performed with the provided host system 80. Here, the barrier 70 plays a role of limiting the energy supplied to the detector 10 and suppressing the overvoltage and overcurrent generated at the time of disconnection or short circuit to a level at which sparks leading to ignition do not occur. Further, the signal converter 72 plays a role of converting a transmission signal between the detector 10 and the host system 80, and monitors the network state (monitoring of disconnection and short circuit of the bus line, etc.).

Although FIG. 1 shows a bus connection centered on one cable portion 90, a tree structure is also possible.

<Signal transmission (detector → signal converter)>
As shown in FIG. 2, the cable unit 90 is a signal transmission line 90A for transmitting a digital signal, which is provided so as to connect between the signal converter 72 and the input / output unit described later of the detector 10. A signal transmission line 90B for transmitting a digital signal and supplying power to the detector 10 from the power supply unit 74 is provided.

The detector 10 transmits signals (unique address / fire signal / abnormal temperature signal / state information, etc.) to the signal converter 72 via signal transmission lines 90A and 90B by two different transmission methods. Here, as the first transmission method on the signal transmission line 90A, Manchester-coded Bus Powered (MBP), in which a Manchester-encoded transmission signal is placed on the power supply line, is used. In MBP, the basic current consumption is supplied to each detector 10, and the communication current (for example, 6 [mA]) is supplied to the detector 10 that performs signal transmission, and the current modulation (for example) in the detector 10 is performed. A current signal is transmitted at ± 6 [mA]) (see FIG. 3). The second transmission method on the signal transmission line 90B is balanced differential signal transmission of voltage amplitude, and the two paired signal lines constituting the signal transmission line 90A have opposite phases. A voltage signal is transmitted (see FIGS. 4 and 5). Both transmission methods are established technologies as transmission methods to dangerous places, and are extremely reliable transmission methods.

In the intrinsically safe explosion-proof detection system 100 according to the present embodiment, a network having high redundancy is realized by transmitting signals using both different transmission methods. Here, the features of each transmission method are shown in Table 1.

Further, both of the above data transmissions are carried out at a low transmission speed of about 30 kbps at the maximum. For example, the transmission speed of the digital signal is 10 kbps to 30 kbps. At the above speeds, it is not necessary to consider impedance matching except for long-distance transmission (several tens of kilometers or more) (there is no need to consider signal reflection due to branching of the transmission line), and the detectors 10 are arranged in a tree shape. It can also be done (see FIG. 6).

The amount of data transmitted by the intrinsically safe explosion-proof detection system 100 is about several tens of bits, and the specifications are sufficiently practical even at the above transmission speed. The signals output separately from the detector 10 by the above method are converted into arbitrary transmission signals (LoRaWAN, Zigbee, LTE-M, etc.) by the signal converter 72, and sent to the host system 80 by the wireless transmitter / receiver 76. Will be sent. Since the transmitted signal has the property of notifying a fire or an abnormal temperature, the signal is transmitted to the host system 80 even when the signal is transmitted from either of the two types.

<Signal transmission (signal converter → detector)>
In the intrinsically safe explosion-proof detection system 100 according to the present embodiment, the signals (address / status confirmation signal, etc.) transmitted from the signal converter 72 to the detector 10 are also transmitted by using two types of methods in combination. .. However, there is a limit to the maximum current that can be supplied at dangerous points, and if the current for MBP transmission is supplied to all the detectors 10, the number of detectors 10 connected to the cable section 90 is greatly limited. .. For example, the permissible output current of the FISCO power supply for the detector 10 (equipment group IIC, protection level ia) installed at the dangerous location (ZONE0) is 183mA (@ output voltage 14 [V]), and the maximum number of connectable units is 9. It becomes a stand. Therefore, in the first transmission method, signal transmission is performed by modulating the voltage applied to the detector 10. As an example, when the voltage applied to the detector 10 during non-transmission is 3 [V], the voltage is lowered to 2.5 V during transmission, and voltage modulation (communication voltage ± 0.5 [V]) is used. A Manchester-encoded voltage is transmitted (see FIG. 7). At this time, the applied current is a value obtained by integrating the basic current consumption required for the operation of abnormality detection by the number of installed units (for example, 1 [mA / unit] x 32 units = 32 [mA]). According to this method, it is possible to suppress the current consumption during communication on the same line as the MBP transmission line, and it is possible to increase the number of detectors 10 that can be installed. In this method, signals can be transmitted to all detectors 10 at the same time. However, the above method is an example, and a transmission method for forming a signal by high-frequency voltage modulation of 0.75 to 1.0 [V] is also possible (see FIG. 8).

In the second transmission method, differential signal transmission is used, and voltage signals having opposite phases are transmitted by two paired signal lines. In this way, the reliability of the intrinsically safe explosion-proof detection system 100 can be improved by making the signal transmission redundant by two different transmission methods.

<Transmission cable>
In the present embodiment, two types of signal transmission lines 90A and 90B (for MBP and differential signal transmission) are housed in one cable section 90 (see FIG. 2). As a result, it is possible to reduce the construction cost by saving wiring and reduce the risk of incorrect cable connection. In addition, the risk of loss of intrinsic safety due to incorrect connection can be reduced. In addition, the cable portion 90 is provided with connectors on both ends so that the connector can be connected to the detector 10, the T-branch connector 90C, and the terminating resistor, so that the construction cost can be further reduced, and erroneous connection or detection can be performed. The risk of foreign matter entering the housing of the vessel 10 can also be reduced.

<Detector configuration>
As shown in FIG. 9, the detector 10 according to the first embodiment of the present invention includes the first sensor 12 that detects infrared light in a band near 4.5 μm of the carbon dioxide resonance radiation band emitted by the flame. , The second sensor 14 that detects infrared light in the band near 4.0 μm in the wavelength band shorter than the carbon dioxide resonance radiation band, and red in the band near 5.0 μm in the wavelength band longer than the carbon dioxide resonance radiation band. It includes a third sensor 16 that detects external light, and a fourth sensor 318 that detects light in a band in the vicinity of 3.0 μm, which is shorter than the above three bands, through the monitoring window 330. Further, the detector 10 includes an amplification unit 18 that amplifies the signal from the first sensor 12, an amplification unit 20 that amplifies the signal from the second sensor 14, and an amplification unit 22 that amplifies the signal from the third sensor 16. The amplification unit 322 that amplifies the signal from the fourth sensor 318, the switch 24 that switches the signals from the amplification units 18, 20, 22, and 322, and the AD conversion unit 26 that converts the signal from the switch 24 into a digital value. And have. Further, the detector 10 includes an arithmetic processing unit 28 that performs processing for detecting a flame or an abnormal temperature, and an input / output unit 32.

The input / output unit 32 outputs to the signal converter 72 as a digital signal that the arithmetic processing unit 28 has detected a flame or an abnormal temperature, and also exchanges a digital signal with the signal converter 72.

Further, as shown in FIG. 9, the detector 10 is provided with a monitoring window 330 in a part of the housing 310A.

The first sensor 12 detects the filter 12A that transmits infrared light in the band near 4.5 μm of the carbon dioxide resonance radiation band emitted by the flame and the infrared light that has passed through the filter 12A, and converts it into an electric signal of a DC component. It includes an array sensor 12B in which detection elements to be converted are arranged in a two-dimensional manner, and an optical lens 12C arranged in front of the filter 12A.

The second sensor 14 detects the filter 14A that transmits infrared light in the band near 4.0 μm in the wavelength band shorter than the carbon dioxide resonance radiation band and the infrared light that has passed through the filter 14A, and detects the electricity of the DC component. It includes an array sensor 14B in which detection elements for converting signals are arranged in a two-dimensional manner, and an optical lens 14C arranged in front of a filter 14A.

The third sensor 16 detects the filter 16A that transmits infrared light in a band near 5.0 μm in a wavelength band longer than the carbon dioxide resonance radiation band and the infrared light that has passed through the filter 16A, and detects electricity as a DC component. It includes an array sensor 16B in which detection elements for converting signals are arranged in a two-dimensional manner, and an optical lens 16C arranged in front of the filter 16A.

The fourth sensor 318 transmits the filter 318A that transmits light in the short wavelength region, which is at least a part of the range including the visible light region of 4.0 μm or less, and the filter 318A, among the natural light transmitted through the monitoring window 330. It includes a detection element 318B that detects light and converts it into an electric signal of a DC component.

Each detection element of the array sensor 12B is arranged so as to correspond to each detection element of the array sensor 14B and each detection element of the array sensor 16B.

Further, the array sensors 12B, 14B, 16B detect infrared light at a predetermined monitoring angle (for example, 90 degrees), and the corresponding detection element of the array sensor 12B, the detection element of the array sensor 14B, And the detection element of the array sensor 16B detects infrared light from the same predetermined region.

Further, each of the optical lenses 12C, 14C, and 16C is composed of one or more lenses. It is desirable that the optical lenses 12C, 14C, and 16C are each composed of two or more lenses. This is to focus as much as possible on the flat surface with respect to the wide monitoring angles of the detection element of the array sensor 12B, the detection element of the array sensor 14B, and the detection element of the array sensor 16B. Further, in order to reduce the loss due to the reflection of the lens, it is possible to increase the sensitivity of the detection element by depositing an antireflection film (AR coat) on the lens. Lens materials include sapphire, chalcogenide glass, silicon, germanium and the like.

In addition, the same sensor as the first sensor 12 may be further provided in order to reliably capture a weak electric signal that detects infrared light in a band in the vicinity of 4.5 μm of the carbon dioxide resonance radiation band.

The detection elements of the first sensor 12 to the fourth sensor 318 are composed of thermopile, but other photoelectromotive power type elements such as InAsSb element, microbolometer element utilizing resistance change, and photoconductivity such as PbSe. It may be composed of type elements. Compared with thermopile and microbolometer, other elements have extremely high infrared detection speed. Therefore, even if the circuit configuration is the same, by increasing the AD conversion speed, it is possible to configure a detector capable of detecting a flame at an extremely high speed.

The amplification units 18, 20, 22, and 222 include an electric signal of each detection element of the first sensor 12, an electric signal of each detection element of the second sensor 14, an electric signal of each detection element of the third sensor 16, and a fourth. The electric signal of the detection element 318B of the sensor 318 is amplified independently.

The switch 24 includes a switch unit (not shown) that sequentially switches the electric signals individually amplified by the amplification units 18, 20, 22, and 222 and aggregates them into one electric signal at a fixed time. Outputs an integrated electrical signal. In addition, without providing the switch 24, an AD conversion unit is provided for each of the amplification units 18, 20, 22, and 322, and the amplified electric signal is individually converted into a digital value in the arithmetic processing unit 28. It may be output.

The arithmetic processing unit 28 is composed of a CPU. The arithmetic processing unit 28 will be described by a functional block divided for each function realization means. As shown in FIG. 10, the arithmetic processing unit 28 includes a signal acquisition unit 40, a detection unit 44, and an input / output control unit 46. There is.

The signal acquisition unit 40 uses the signal output from the AD conversion unit 26 to obtain the value of the electric signal from each detection element of the first sensor 12, the value of the electric signal from each detection element of the second sensor 14, and the third sensor. The value of the electric signal from each of the 16 detection elements and the value of the electric signal from the detection element 318B of the fourth sensor 318 are acquired.

The detection unit 44 includes the value of the electric signal from each detection element of the first sensor 12, the value of the electric signal from each detection element of the second sensor 14, and the value of the electric signal acquired by the signal acquisition unit 40, and the third sensor 16. Based on the value of the electric signal from each detection element, it is determined whether or not a flame or an abnormal temperature is detected for each detection element of the array sensor 12B. Since the determination method is the same as the method described in Patent Document (International Publication No. 2018/198504), the description thereof will be omitted.

Further, the detection unit 44 determines, among the detection elements of the array sensor 12B, a predetermined position with respect to the detection element determined to have detected the flame as a fire position.

When the detector 10 is installed, the predetermined position with respect to the detection element may be set by measuring the detection position in the real space for each detection element using the position measuring instrument.

The detection unit 44 determines the scale W, which is the spatial magnitude of the flame, based on the value of the electric signal from the detection element determined to have detected the flame.

When it is determined that a disaster has been detected, the detection unit 44 controls the input / output control unit 46 so as to notify the fire position. For example, the input / output control unit 46 transmits a fire signal to the signal converter 72 via the cable unit 90.

Further, the detection unit 44 determines that the value of the electric signal from the detection element of the third sensor 16 and the value of the electric signal from the detection element 318B of the fourth sensor 318 satisfy predetermined conditions. The monitoring window 330, the third sensor 16, the fourth sensor 318, the amplification units 18, 20, 22, 222, the switch 24, the AD conversion unit 26, or the arithmetic processing unit 28 determine that the abnormal state is present and notify the abnormal state. The input / output control unit 46 is controlled so as to do so. For example, the input / output control unit 46 causes the signal converter 72 to transmit a signal indicating window dirt or other abnormality via the cable unit 90.

<Operation of intrinsically safe explosion-proof detection system>
Next, the operation of the intrinsically safe explosion-proof detection system 100 according to the first embodiment of the present invention will be described.

First, an individual address is assigned to each of the detectors 10 installed in the intrinsically safe explosion-proof detection system 100. As a result, in the data transmission between the detector 10 and the signal converter 72, a signal including an address and various information is exchanged. As an example, when 32 detectors 10 are connected on the cable unit 90, the address unit is represented by 5 bits, and several bits of state information (fire signal, abnormal temperature, window dirt, fire position, etc.) are behind it. Is added (Fig. 11). This address can be arbitrarily changed by signal transmission from the host system 80, a DIP switch provided in the detector 10, or the like.

Further, the detector 10 repeatedly executes the process of detecting the flame or the abnormal temperature at regular intervals. Further, the detector 10 repeatedly executes the process of determining the abnormal state of the detector 10 at regular intervals.

At this time, in the intrinsically safe explosion-proof detection system 100, the following data is normally exchanged.

<Data transfer (normal time)>
In the intrinsically safe explosion-proof detection system 100, the state of each detector 10 is normally checked in a polling format. Specifically, the signal converter 72 outputs a status information request signal to each detector 10 (each address) in order (S1), and the designated detector 10 outputs the information (address and no abnormality / window dirt). / Other abnormalities, etc.) are output (S2). This is performed for each detector 10 in the order of addresses, and the state information collected when one cycle is completed is transmitted to the host system 80 by wireless communication. This is repeated in a fixed time cycle (Fig. 12).

By this state check, it is possible to identify the disconnection point, which will be described later. The disconnection location can be specified by the number and address of the detectors 10 that do not respond to the state information request signal from the signal converter 72.

As described above, by periodically diagnosing the functions of the detector 10 and the network and transmitting the diagnosis result to the host system 80 by wireless communication, not only the reliability of the intrinsically safe explosion-proof detection system 100 can be improved, but also maintenance Costs can be reduced.

Further, when the detector 10 detects a flame or an abnormal temperature, or when the detector 10 is determined to be in an abnormal state, the intrinsically safe explosion-proof detection system 100 transfers the following data.

<Data transfer (when fire is detected, when abnormal temperature is detected, when abnormal condition is judged)>
When an abnormal state is detected by an arbitrary detector 10, the information (address and fire signal / abnormal temperature signal, etc.) is output from the detector 10 to the signal converter 72 as shown in FIG. (S3). Upon receiving this signal input, the signal converter 72 transmits a fire signal, an abnormal temperature signal, an abnormal state signal, or the like to the host system 80 via the wireless transmitters / receivers 76 and 88 (S4). In addition, the signal converter 72 outputs a signal to all the detectors 10 at the time when the information of the address portion of the above signals is transmitted from the detectors 10 of the address (S5). ). In response to the above signal transmission, all detectors 10 except the detector 10 stop outputting the fire signal, abnormal temperature signal, or abnormal state signal until after an arbitrary time elapses, and an arbitrary time (in millisecond order) elapses. If there is a detector 10 that has detected an abnormality by then, a fire signal, an abnormal temperature signal, or an abnormal state signal is output after the lapse of the arbitrary time. As a result, it is possible to prevent loss or communication failure due to overlapping of the signals output from the plurality of detectors 10 with a slight time difference. The above time can be arbitrarily changed according to the amount of signal to be transmitted (when the output information is only a fire signal, an abnormal temperature signal, or an abnormal state signal, it is short, and the abnormal position information, temperature information, etc. are also combined. If you want to output it, make it longer, etc.).

If the consent signal is not transmitted from the signal converter 72 even after a lapse of a certain period of time, the detector 10 outputs a fire signal or the like again and repeatedly executes this until the consent signal is transmitted. If a fire signal or the like is output from two or more detectors 10 at the same time, or if a fire signal or the like is output from an arbitrary detector 10 during the status check of the detector 10, two or more detectors are output. The combined signal is input to the signal converter 72 (FIG. 14). In this case, depending on the conditions, the signal cannot be restored and may be lost. Therefore, the state of each detector 10 is checked in a polling format. Specifically, as shown in FIG. 15, when it is determined that the signal converter 72 has output from a plurality of detectors 10, the address and status information request signals are output to all the detectors 10 in order. Then, each designated detector 10 outputs the information (address and no abnormality / fire signal, etc.) (S7). This is performed for each detector 10 in the order of addresses, and when a fire signal, an abnormal temperature signal, or an abnormal state signal is confirmed, the information is transmitted to the host system 80 by wireless communication (S8). As a method for determining that the signal converter 72 has output from a plurality of detectors 10, for example, in MBP transmission, there is a method of monitoring the output current from the power supply and making a determination based on the amount of increase in the current. .. On the other hand, regarding balanced differential signal transmission, although there is a method of determining by increasing the amplitude of the signal input to the signal converter 72, it becomes difficult to determine when the signals completely overlap.

Therefore, when any signal is input by the transmission method, reliable transmission is performed by checking the state of each detector 10 in a polling format in the same manner as the above MBP. However, this method is an example, and there is also a method such as carrier wave detection multiple access / collision detection (CSMA / CD) in which detectors 10 monitor the status of signals flowing through the cable section 90 and adjust the line usage right. Applicable. As described above, by using polling that is simple and has high transmission reliability, it is possible to prevent the loss of the fire signal from the detector 10 and the communication failure, and improve the reliability of data transfer in both transmission methods.

<Countermeasures against disconnection / short circuit>
When a wire break or short circuit occurs in the cable portion 90, there is a possibility that an arbitrary detector 10 may not be able to monitor (a state in which power is not supplied, a state in which signal transmission is not performed, etc.) (FIG. 16). The intrinsically safe explosion-proof detection system 100 monitors disconnection and short circuit by the following method, and transmits a disconnection / short circuit alarm to the host system 80 by wireless communication.

(Disconnection monitoring)
In the intrinsically safe explosion-proof detection system 100, as described above, the state of the detector 10 is checked at regular intervals. Therefore, if there is no response to the state information request signal from the signal converter 72, it is suspected that a disconnection has occurred. Here, since a unique address is assigned to the detector 10, as shown in FIG. 16A, when a disconnection occurs on the cable portion 90, or as shown in FIG. 16B. When a disconnection occurs on the branch line of the cable portion 90, the signal converter 72 can identify the disconnection location based on the address where there is no response after one cycle of the state check.

(Short circuit monitoring)
In the intrinsically safe explosion-proof detection system 100, when a short circuit occurs on the cable portion 90 as shown in FIG. 16 (C), or when a short circuit occurs on the branch line of the cable portion 90 as shown in FIG. 16 (B). If it occurs, the short-circuit location cannot be specified, but the short-circuit can be detected by monitoring the short-circuit current with the signal converter 72 or the power supply unit 74.

<Battery maintenance of power supply>
The intrinsically safe explosion-proof detection system 100 periodically replaces the primary battery of the power supply unit 74 or charges the secondary battery. At this time, since the number of power supply units 74 is smaller than the number of detectors 10, maintenance of the battery of the power supply unit 74 can be reduced. The power supply unit 74 may be an external power source as long as the intrinsic safety is ensured. In that case, maintenance of the battery is not required, so that the management cost can be further reduced.

As described above, according to the intrinsically safe explosion-proof detection system according to the embodiment of the present invention, a power source is supplied by supplying electric power from a power source unit to a plurality of detectors via a signal transmission line. Since the number of units can be reduced, the management cost of the power supply unit can be reduced.

Further, each of the input / output unit and the signal converter of the detector has a simple configuration and is highly reliable by transmitting and receiving the digital signal on a plurality of signal transmission lines using different signal transmission methods. An intrinsically safe explosion-proof detection system can be provided.

In addition, the cable section that includes multiple signal transmission lines ensures that the fire or abnormal temperature detected by the detector is transmitted to the higher-level system even if a problem (disconnection or short circuit) occurs in the cable section, ensuring a safety level. A high intrinsically safe explosion-proof detection system can be realized.

In addition, a fire / abnormal temperature monitoring environment at a dangerous place (ZONE0), which has the strictest technical requirements, can be realized at low cost.

In addition, multiple detectors installed in the dangerous place are connected to one cable part by T-branch, and are installed in the non-dangerous place via the barrier, the signal converter, and the wireless transmitter / receiver. Performs half-duplex communication with the system. Specifically, the signals transmitted from the detector to the signal converter (unique address / fire signal / abnormal temperature signal / state information, etc.) are the current signal supplied by the Manchester coded bus and the balanced differential signal transmission. It is redundantly transmitted as two types of voltage signals. There are two types of signals (address / status confirmation signal, etc.) transmitted from the signal converter to the detector: voltage transmission generated by modulation of the voltage applied to the detector, and voltage signal by differential signal transmission. It is transmitted as a signal in a redundant manner. As a result, the fire signal or the abnormal temperature can be reliably transmitted to the host system.

Further, by using the voltage transmission by the voltage modulation, it is possible to suppress the current supplied to the dangerous place, and it is possible to increase the number of detectors installed in the dangerous place.

Further, by carrying out each of the two types of signal transmission at a low transmission speed of about several tens of kbps, a network capable of tree branching can be obtained.

Further, the construction cost can be reduced by accommodating the above two types of signal transmission lines in one cable section.

In addition, polling from the signal converter periodically diagnoses the functions of the detector and network, and transmission to the host system by wireless communication improves the reliability of the intrinsically safe explosion-proof detection system and maintenance costs. Etc. are reduced.

Further, when a fire signal or the like is output from a plurality of detectors at the same time, polling from the signal converter prevents the fire signal from failing in communication and improves the reliability of data transfer.

[Second Embodiment]
<System configuration>
Hereinafter, the intrinsically safe explosion-proof detection system according to the second embodiment of the present invention will be described. The parts having the same configuration as that of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 17, the intrinsically safe explosion-proof detection system 200 according to the second embodiment of the present invention includes a plurality of detectors 10, barriers 70A and 70B, signal converters 72A and 72B, and a power supply unit. It includes 74A and 74B, wireless transmitters and receivers 76A and 76B, and a host system 80. A plurality of sets including a plurality of detectors 10, barriers 70A and 70B, signal converters 72A and 72B, power supply units 74A and 74B, and wireless transmitters and receivers 76A and 76B are provided.

The signal converter 72A and the plurality of detectors 10 are connected by a cable unit 290A, and the signal converter 72B and the plurality of detectors 10 are connected by a cable unit 290B. The power supply units 74A and 74B are composed of a primary battery or a secondary battery.

As described above, in the present embodiment, the first medium configuration including the cable unit 290A, the wireless transmitter / receiver 76A, the power supply unit 74A, the signal converter 72A, and the barrier 70A, the cable unit 290B, the wireless transmitter / receiver 76B, and the power supply A second neutral configuration including a portion 74B, a signal converter 72B, and a barrier 70B is provided. In accordance with this, each detector 10 includes two input / output units 32, and one input / output unit 32 is connected to the first neutral configuration and is flamed by the arithmetic processing unit 28 via the cable unit 290A. Is output to the signal converter 72A as a digital signal, and a digital signal is exchanged with the signal converter 72A. Further, the other input / output unit 32 is connected to the second medium configuration, and outputs the detection of the flame by the arithmetic processing unit 28 as a digital signal to the signal converter 72B via the cable unit 290B, and also outputs a signal. It sends and receives digital signals to and from the converter 72B.

The cable portions 290A and 290B include a signal transmission line 90A and a signal transmission line 90B, similarly to the cable portion 90 of the first embodiment.

In the intrinsically safe explosion-proof detection system 200, the lines from the cable portions 290A and 290B to the wireless transmitters and receivers 76A and 76B are duplicated. By duplicating the network in this way, it is possible to avoid a state in which monitoring becomes impossible in the event of a disconnection or short circuit (FIG. 18). Specifically, when the signal converter 72A or 72B detects a disconnection / short circuit in one network by the same method as in the first embodiment, a short circuit alarm is transmitted to the host system 80 by wireless communication and a short circuit alarm is transmitted. , Automatically switch the transmission line to the other network. As a result, it is possible to avoid a state in which fire / abnormal temperature monitoring becomes impossible due to disconnection or short circuit, and a highly reliable fire monitoring environment can be constructed.

Since a unique address is assigned to the detector 10, as shown in FIG. 18 (A), when a disconnection occurs on the cable portion 290B, or as shown in FIG. 18 (B), When a disconnection occurs on the branch line of the cable portion 290B, the signal converter 72B can identify the disconnection location based on the address where there is no response after one cycle of the state check. Further, as shown in FIG. 18C, when a short circuit occurs on the cable portion 290B, or as shown in FIG. 18B, when a short circuit occurs on the branch line of the cable portion 290B, the short circuit occurs. Although the location cannot be specified, a short circuit can be detected by monitoring the short circuit current with the signal converter 72B or the power supply unit 74B.

As described above, according to the intrinsically safe explosion-proof detection system according to the second embodiment, by duplicating the line from the cable section to the power supply section, further redundancy can be achieved, and a fire or an abnormal temperature can be achieved. Realize a reliable network for monitoring at low cost. In this case, it is a quadruple system in terms of signal transmission. Due to the duplication, even if a disconnection or short circuit occurs, the fire or abnormal temperature monitoring environment can be continued. In actual operation, it is possible to use a detector with two cable connection connectors as a standard product, and to select the presence or absence of duplication according to the safety level (SIL) and cost required by the customer. be.

<Modification example>
The present invention is not limited to the above-described embodiment, and various modifications and applications are possible without departing from the gist of the present invention.

For example, the case where an array sensor is used in all of the first sensor 12, the second sensor 14, and the third sensor 16 of the detector 10 has been described as an example, but the present invention is not limited thereto. An array sensor may be used in at least one of the first sensor 12, the second sensor 14, and the third sensor 16. For example, the first sensor 12 may be configured by using the array sensor 12B, and the second sensor 14 and the third sensor 16 may be configured by using one detection element instead of the array sensor.

Further, the first sensor 12, the second sensor 14, and the third sensor 16 are configured by using one detection element instead of the array sensor, and infrared light in the band from around 2.0 μm to around 5.0 μm. The fifth sensor may be configured to further include a fifth sensor for detecting the above, and the fifth sensor may be configured by using an array sensor. In this case, the detection unit sets a predetermined position with respect to the detection element having the maximum electric signal value based on the electric signal value detected by each detection element of the array sensor of the fifth sensor. , It may be judged as a fire position.

Further, the present invention may be applied to a system such as a gas detector or a temperature sensor that outputs an alarm indicating that a predetermined abnormality has been detected at a predetermined threshold value or higher. For example, the present invention is applied to a system that outputs an alarm indicating that a predetermined abnormality is detected when the humidity, pressure, vibration, impact, gas concentration, sound, or rotation detected by the sensor is equal to or higher than a threshold value. May be applied. Further, the present invention may be applied to a system that outputs an alarm when a liquid leak is detected based on the sensor information detected by the sensor. Further, the present invention may be applied to an intrinsically safe explosion-proof detection system using a field device in which a plurality of units are installed in a row at a dangerous place as a detector.

Further, the case where MBP is used as the first transmission method has been described as an example, but the present invention is not limited to this, and for example, Manchester code by voltage modulation or Ethernet (registered trademark) may be used. When Ethernet (registered trademark) is used as the first transmission method, power can be supplied by a communication line using a technology called PoE (Power over Ethernet).

10 Detector 28 Arithmetic processing unit 32 Input / output unit 70, 70A, 70B Barrier 72, 72A, 72B Signal converter 74, 74A, 74B Power supply unit 76, 76A, 76B Wireless transmitter / receiver 80 Higher system 90, 290A, 290B Cable unit 90A, 90B Signal transmission line 100, 200 Intrinsic safety explosion-proof detection system

Claims (18)

Based on the sensor information detected by the sensor, a detection unit that monitors environmental information or determines whether or not a predetermined abnormality has been detected, and a signal converter that uses the monitoring result or determination result by the detection unit as a digital signal. Multiple detectors including the signal converter and the input / output unit that sends and receives digital signals while outputting to
A signal converter that relays the transmission and reception of signals between each of the plurality of detectors and the host device, and
A power supply unit that supplies power to each of the plurality of detectors,
A signal transmission line for transmitting the digital signal provided so as to connect between the signal converter and the input / output unit of each of the plurality of detectors is included, and the detector is provided with a signal transmission line. And the transmission cable unit that supplies power from the power supply unit
A wireless transmission / reception unit that transmits / receives signals between the host device and the signal converter by wireless communication.
Intrinsically safe explosion-proof detection system including. The transmission cable unit includes a plurality of the signal transmission lines.
The first aspect of claim 1, wherein each of the input / output unit and the signal converter of each of the plurality of detectors transmits / receives the digital signal on the plurality of signal transmission lines using different signal transmission methods. Intrinsic safety explosion-proof detection system. Each of the input / output unit and the signal converter uses the digital signal generated by modulation of the voltage applied to the input / output unit or the amplitude of the voltage as one of the signal transmission methods, and the digital signal is used. The intrinsically safe explosion-proof detection system according to claim 2, wherein signals are sent and received. Each of the input / output unit and the signal converter uses the digital signal generated by modulating the current flowing from the input / output unit to the signal converter as one of the signal transmission methods, and uses the digital signal. The intrinsically safe explosion-proof detection system according to claim 2 or 3, wherein signals are sent and received. Claims 2 to claim that each of the input / output unit and the signal converter uses Ethernet (registered trademark) as one of the signal transmission methods to send and receive the digital signal and supply the power. Item 4. The intrinsically safe explosion-proof detection system according to any one of items 4. The intrinsically safe explosion-proof detection system according to any one of claims 2 to 5, wherein the transmission cable unit includes one transmission cable containing the plurality of signal transmission lines. The intrinsically safe explosion-proof detection system according to any one of claims 1 to 6, wherein the power supply unit is composed of a primary battery or a secondary battery. The one according to any one of claims 1 to 7, further comprising a barrier unit provided between the input / output unit and the signal converter for limiting the current and voltage supplied from the power supply unit. Intrinsic safety explosion-proof detection system. Each of the plurality of detectors is connected to the transmission cable section and is connected to the transmission cable section.
The intrinsically safe explosion-proof detection system according to any one of claims 1 to 8, wherein each of the plurality of detectors performs bidirectional communication with the signal converter. A unique address is assigned to each of the plurality of detectors in advance.
The intrinsically safe explosion-proof detection system according to any one of claims 1 to 9, wherein the digital signal transmitted and received between the detector and the signal converter includes an address of the detector. The signal converter monitors the state of each detector, the state of the transmission cable unit, and the determination result in order by polling at regular time intervals, and the state of the detector or the state of the transmission cable unit is in an abnormal state. In some cases, or when the determination result indicates that the predetermined abnormality has been detected, or when the detector outputs a digital signal of the determination result indicating that the predetermined abnormality has been detected. The intrinsically safe explosion-proof detection system according to any one of claims 1 to 10, wherein a predetermined message is transmitted to a higher-level device by wireless communication. The signal converter is a digital signal indicating that the state of the detector is in an abnormal state from two or more detectors, or a digital signal indicating that the determination result has detected the predetermined abnormality. The intrinsically safe explosion-proof detection system according to any one of claims 1 to 11, which monitors the state of each detector and the determination result in order when there is an output, and transmits the monitoring result to a higher-level device. The intrinsically safe explosion-proof detection system according to claim 12, wherein the abnormal state of the transmission cable unit is a disconnection or short circuit of the signal transmission line or the power cable. The detector includes a plurality of input / output units.
A plurality of medium configurations including the transmission cable unit, the power supply unit, and the signal converter are provided.
The essence of any one of claims 1 to 13, wherein the digital signal is exchanged using any one of the plurality of input / output units and any one of the plurality of intermediate configurations. Safety explosion-proof detection system. The detection unit monitors humidity, pressure, vibration, shock, gas concentration, sound, or rotation as the environmental information, or temperature, humidity, pressure, vibration, shock, gas concentration, as the predetermined abnormality. The intrinsically safe explosion-proof detection system according to any one of claims 1 to 14, which determines whether or not an abnormality related to sound or rotation, a fire, or a liquid leak is detected. Claim that any or all of the detector, the power supply unit, the signal converter, the wireless transmission / reception unit, and the transmission cable unit are installed in a dangerous place (ZONE 0) specified by an explosion-proof guideline for factory electrical equipment. The intrinsically safe explosion-proof detection system according to any one of claims 1 to 15. The detector is
A first band filter that transmits infrared light in the first band including the peak wavelength of the carbon dioxide resonance radiation band,
A second band filter that transmits infrared light in a second band different from the first band and whose center of the band is located away from the center of the carbon dioxide resonance radiation band, and the first band and A plurality of band filters including a third band filter provided at a position where the band center is distant from the band center of the carbon dioxide resonance radiation band while transmitting infrared light of a third band different from the second band. ,
A detection unit provided for each of the plurality of band filters and including a detection element for detecting infrared light transmitted through the band filters and converting the infrared light into an electric signal, and at least one of the plurality of band filters. The detection elements provided for each of them are a detection unit configured as an array sensor arranged in a two-dimensional manner and a detection unit.
A detector that monitors the temperature or determines whether a flame or abnormal temperature has been detected based on the electrical signal detected by each detection element.
The intrinsically safe explosion-proof detection system according to claim 15. The one according to any one of claims 1 to 17, wherein a plurality of sets including the plurality of detectors, the signal converter, the power supply unit, the transmission cable unit, and the wireless transmission / reception unit are included. Intrinsic safety explosion-proof detection system.

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