CN111264034A

CN111264034A - Receiving circuit and communication device

Info

Publication number: CN111264034A
Application number: CN201880069381.5A
Authority: CN
Inventors: 立海优
Original assignee: Nippon Seiki Co Ltd
Current assignee: Nippon Seiki Co Ltd
Priority date: 2017-10-25
Filing date: 2018-09-25
Publication date: 2020-06-09
Also published as: JPWO2019082578A1; WO2019082578A1; JP7185833B2

Abstract

Provided are a receiving circuit and a communication device which can maintain receiving sensitivity and satisfy explosion-proof requirements. A receiving circuit (65) in a detection device (communication device) (10) is provided with: an antenna circuit (66), wherein the antenna circuit (66) is composed of an antenna (64) and a capacitor (C); first and second limiter circuits (67, 68) each composed of a zener diode (Z11, Z21) and a resistor (R11, R21); and an electronic circuit (63), wherein one end of the antenna circuit (66) and one end of the electronic circuit (63) are connected via a first limiter circuit (67), and the other end of the antenna circuit (66) and the other end of the electronic circuit (63) are connected via a second limiter circuit (68).

Description

Receiving circuit and communication device

Technical Field

The present invention relates to an improved receiving circuit and communication device.

Background

Communication devices are known in which wireless communication is possible between a control substrate received inside a housing and a device provided outside the housing. As a conventional technique relating to such a communication device, there is a technique disclosed in patent document 1.

A communication apparatus such as that disclosed in patent document 1 is of a type that is assumed to be used at a dangerous place. The dangerous place refers to a place where there is a danger that an explosive gas and air are mixed to generate a dangerous atmosphere of not less than an explosion lower limit in a general factory or the like. Assume that the communication device used at the hazardous location must be required to be suitable for intrinsic safety explosion proof requirements (jis S C60079).

For communication devices used in hazardous locations, inductance values and capacitances are limited to suit intrinsically safe explosion-proof conditions. The upper limit of the inductance value that can be used inside the circuit depends on the current and the upper limit of the capacitance value depends on the voltage. Thus, although the current and voltage are limited by increasing the resistance value of the resistor and increasing the rated value of the zener diode, if a value satisfying the intrinsic safety explosion-proof requirement is considered, there is a problem that the receiving sensitivity is lowered.

Documents of the prior art

Patent document

Patent document 1: JP 2009 and 054940 publication

Disclosure of Invention

Problems to be solved by the invention

The invention provides a receiving circuit and a communication device which can maintain receiving sensitivity and meet explosion-proof requirements.

Means for solving the problems

The receiving circuit of the present invention is characterized by comprising:

an antenna circuit configured from an antenna and a capacitor;

first and second limiter circuits formed of a zener diode and a resistor;

an electronic circuit for controlling the operation of the electronic circuit,

wherein one end of the antenna circuit and one end of the electronic circuit are connected via the first limiter circuit, and the other end of the antenna circuit and the other end of the electronic circuit are connected via the second limiter circuit;

the capacitor in the antenna circuit is provided on the first and second limiter circuit sides;

the resistors in the first and second limiter circuits are provided on the electronic circuit side.

The communication device of the present invention includes the above-described receiving circuit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a receiving circuit and a communication apparatus that can satisfy explosion-proof requirements while maintaining reception sensitivity can be provided.

Drawings

Fig. 1 is a diagram schematically showing a plant device state collection system using a detection device (communication device) according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view and a plan view of the detecting unit shown in FIG. 1;

FIG. 3 is a diagram showing a first embodiment of a receiving circuit of the detecting device shown in FIG. 2;

FIG. 4 is a diagram showing a second embodiment of a receiving circuit of the detecting device shown in FIG. 2;

fig. 5 is a diagram showing a measurement value of a communicable distance with a portable terminal and a communication result in the second embodiment of the receiving circuit of the detection apparatus shown in fig. 2.

Detailed Description

Embodiments of the present invention are described below with reference to the drawings.

Refer to fig. 1. Fig. 1 shows a plant equipment state collection system 1 in a petrochemical plant. Petrochemical plants are very large. For this reason, the detection means (communication means) 10 detects each means, and the data storage management means 5 manages the detected information.

More specifically, the description will be given. The plurality of detection devices 10 are installed in the hazardous location DA by being mounted on each device in the factory. The information detected by these detection devices 10 is transmitted to the network construction device 4 via the relay 3 or directly, and is transmitted to the data storage management device 5. A manager of the plant can confirm the information stored in the data storage management apparatus 5 using a notebook personal computer (management terminal), not shown.

Although three detection devices 10 are shown in fig. 1, the number of detection devices 10 may be four or more, or may be one or two.

The state detected by the detection device 10 includes temperature, vibration, and the like. When the abnormality of the state is recognized, the manager guides the worker to the detection device 10, in which the abnormality has been detected, to confirm the state.

Refer to fig. 2. After performing a work such as maintenance of the device in which the abnormality has occurred, the worker places the portable terminal 6 (communication device 6) such as a tablet terminal on the detection device 10, and performs communication so as to transmit the work completion to the data storage management device 5. The communication between the portable terminal 6 and the detection device 10 may employ short-range wireless communication, such as an RFID (radio frequency identifier) standard defined by ISO/IEC 14443, an NFC (near field communication) standard defined by ISO/IEC 18092, or the like. For example, by the short-range wireless communication, the work content written from the portable terminal 6 to the detection device 10 is directly transmitted from the detection device 10 to the network construction device 4 via the relay 3 or from the detection device 10, and is further transmitted from the network construction device 4 to the data storage management device 5. The portable terminal 6 may write various information such as authentication information and operation conditions into the detection device 10 by short-range wireless communication when the detection device 10 is attached.

Fig. 2 (a) shows a cross-sectional view of the detection device 10, and fig. 2 (b) shows a plan view of the detection device 10. The main structural elements of the detection device 10 include a metal housing 11; a window member 50 opened in the opening 43 in the housing 11; a control substrate 14 fixed to the housing 11; an auxiliary substrate 60 connected to the control substrate 14; an electronic circuit 63 mounted on the auxiliary substrate 60; a flexible printed circuit board 61 connected to the auxiliary board 60, provided in proximity to the bottom surface of the window member 50, and configured to perform short-range wireless communication; a communication module 16, the communication module 16 being mounted on the control substrate 14; a sensor 70, the sensor 70 being connected to the control substrate 14, for detecting a state of the apparatus; a sensor connector 21, the sensor connector 21 connecting the control substrate 14 to the sensor 70 through a cable 21 a; a battery module 80, the battery module 80 being composed of a battery or the like, and supplying power to the control substrate 14; a battery connector 22, the battery connector 22 connecting the control substrate 14 and the battery module 80 via a cable 22 a; a communication antenna 23, the communication antenna 23 being disposed on the top surface of the housing 11; a connector 24, the connector 24 connecting the control substrate 14 and the communication antenna 23 via a cable 24 a; a connector 25, the connector 25 connecting the cable 21a and the connector 71 of the sensor 70; a connector 62, wherein the connector 62 connects the flexible printed circuit substrate 61 and the auxiliary substrate 60 via a cable 62 a. The direction of the communication antenna 23 from the center of the detection device 10 is the positive direction of the x-axis, the depth direction from the center of the detection device 10 when the communication antenna 23 is placed in the positive direction of the x-axis is the positive direction of the y-axis, and the upper side in the vertical direction of the detection device 10 is the positive direction of the z-axis.

The housing 11 is composed of a first separator 30 provided at a lower portion and opened at an upper portion, and a second separator 40 stacked on the first separator 30. The first and

second segments

30 and 40 are fastened by bolts and nuts not shown in the drawings. The surface of the housing 11 is subjected to surface treatment such as painting as necessary.

The control substrate 14 is a multilayer printed circuit substrate. The control substrate 14 is fixed to the inner surface of the second partition 40 by screws 26. The control substrate 14 is grounded. The control substrate 14 may be provided with a light emitting element for switching between lighting on, turning off when on, and turning off when on by the control substrate 14.

The communication module 16 is formed of, for example, a circuit including at least one processor (e.g., a Central Processing Unit (CPU)), at least one Application Specific Integrated Circuit (ASIC), and/or at least one Field Programmable Gate Array (FPGA), and the like, and may perform at least a part of the functions of the detection apparatus 10 shown in fig. 1. The communication module 16 is automatically activated at a set interval, and has a function of transmitting information detected by the sensor 70 and information input from the portable terminal 6 by short-range wireless communication to the relay 3 and the network construction device 4 via the communication antenna 23.

The first divided body 30 is constituted by a bottom portion 31 having a substantially rectangular shape as viewed from the bottom and a lower side wall portion 32 rising from each edge of the bottom portion 31.

A part of the bottom portion 31 protrudes downward to form a connector housing 33 for receiving the connector 25.

The lower side wall portion 32 is grounded.

The second divided body 40 is constituted by a lid portion 41 having a substantially rectangular shape in plan view and an upper side wall portion 42 descending from each edge of the lid portion 41.

A substantially rectangular opening 43 is opened in the center of the cover 41. The area of the opening 43 when viewed from the plane is set to 1600mm²The following. An antenna mounting hole (not shown) for mounting the communication antenna 23 is opened adjacent to the opening 43.

The upper side wall portion 42 is connected to the lower side wall portion 32.

The window member 50 is provided to close the opening 43 of the second partition body 40. The raw material of the window member 50 is made of resin having electrical insulation and transmitting radio waves or magnetism for short-range wireless communication.

The auxiliary substrate 60 employs a multilayer printed circuit substrate. The auxiliary substrate 60 has an electronic circuit 63. The auxiliary substrate 60 is connected to the control substrate 14 through the spacer 27, BtoB (board-to-board)

connectors

28 and 29.

The auxiliary substrate 60 is connected to a flexible printed circuit substrate 61 having an antenna 64 (refer to fig. 3) through a cable 62a and a connector 62. Since the flexible printed circuit substrate 61 has flexibility, the degree of freedom of arrangement is high. The antenna 64 can be located closer to the window member 50, and high communication performance can be ensured.

Reference is also made to the first embodiment of the receiving circuit 65 of fig. 3. The detection device 10 includes a receiving circuit 65 for performing short-range wireless communication with the portable terminal 6. The receiving circuit 65 is constituted by an electronic circuit 63, an antenna circuit 66, and first and

second limiter circuits

67 and 68. The capacitor C of the antenna circuit 66, the first and

second limiter circuits

67 and 68, and the electronic circuit 63 are mounted on the auxiliary substrate 60, and the antenna 64 of the antenna circuit 66 is mounted on the flexible printed circuit substrate 61.

The electronic circuit 63 is formed of, for example, an Integrated Circuit (IC), and is activated by short-range wireless communication with the portable terminal 6 or supply of electric power from the control board 14 through the

connectors

28 and 29, and has a function of storing information input from the communication module 16 or the portable terminal 6, and a function of transmitting the stored information to the communication module 16 or the portable terminal 6.

The antenna 64 is an antenna for performing short-range wireless communication with the mobile terminal 6. The antenna 64 is formed of a patterned antenna or a coil formed on the flexible printed circuit substrate 61 by a material having conductivity.

The capacitor C of the antenna circuit 66 is used to adjust the resonance frequency of the antenna 64, and its capacity is determined according to the frequency of the short-range wireless communication.

In the first and

second limiter circuits

67 and 68, resistors R1 and R2 are connected in series to wirings L1 and L2, respectively (one resistor is provided for each wiring). The resistors R1 and R2 function as current limiting elements that limit the current supplied from the wirings L1 and L2 to the receiving circuit 65. Further, on the wirings L1 and L2, zener diodes Z11, Z21 are connected in parallel between the capacitor C of the antenna circuit 66 and the resistors R1 and R2 (one zener diode is provided for each wiring). In the zener diodes Z11 and Z21, the negative electrodes are connected to the wirings L1 and L2, and the positive electrodes are grounded. The zener diodes Z11, Z21 function as voltage limiting elements that limit the voltage applied to the receiving circuit 65 from the wirings L1 and L2. Thus, for intrinsic safety explosion-proof requirements, a protection level that does not apply the concept of counting failures can be met.

Reference is made to a second embodiment of the receiving circuit 65 of fig. 4. In the first and

second limiter circuits

67 and 68, resistors R1 and R2 are connected in series to wirings L1 and L2, respectively (one resistor is provided for each wiring). The resistors R1 and R2 function as current limiting elements that limit the current supplied from the lines L1 and L2 to the receiving circuit 65. Further, on the wirings L1 and L2, two zener diodes are connected in parallel between the capacitor C of the antenna circuit 66 and the resistors R1 and R2. That is, the zener diodes Z11 and Z12 are connected in parallel to the wiring L1, and the zener diodes Z21 and Z22 are connected in parallel to the wiring L2 (two zener diodes are provided for each wiring). In the zener diodes Z11, Z12, Z21, and Z22, the cathodes are connected to the wirings L1 and L2, and the anodes are grounded. The zener voltages of the zener diodes Z11, Z12, Z21, and Z22 are substantially the same, but are not uniform due to the unevenness. Therefore, one of the zener diodes Z11, Z12 and one of Z21, Z22 function as voltage limiting elements that limit the voltage applied to the receiving circuit 65 from the wirings L1 and L2. The other of the zener diodes Z11 and Z12 and the other of Z21 and Z22 do not function as voltage limiting elements and are used for redundancy. Therefore, all protection levels can be met for the requirements of intrinsic safety and explosion prevention.

In the first and second embodiments, the parasitic capacitance of the zener diodes of the first and

second limiter circuits

67 and 68 may be 30pF or less, and the resistance value of the resistor may be 51 Ω. Therefore, the receiving sensitivity can be kept, and meanwhile, the requirement of intrinsic safety explosion prevention can be met.

In the intrinsic safety explosion-proof requirement, a capacitance value that can be used in conjunction with a voltage applied to a circuit is determined, and the voltage can be determined by limiting electric power flowing from an external circuit using a zener voltage of a zener diode. However, since the parasitic capacitance of the zener diode functions as a low-pass filter, the reception signal of the antenna 64 is attenuated, and the communication performance (reception sensitivity) is lowered. Therefore, it is found that the parasitic capacitance of the zener diode is preferably sufficiently small, and in the present invention, it is 30pF or less.

In the intrinsically safe explosion-proof requirement, an inductance value that can be used with a current applied in a circuit is determined, and the current can be determined by limiting an electric power flowing from an external circuit using a resistor. However, when the resistance value is increased, the reception sensitivity is lowered, and when the resistance value is decreased, the current flowing through the circuit is increased, so that it is difficult to satisfy the intrinsically safe explosion-proof requirement. Therefore, the present invention has found that the resistance value satisfying the requirements for intrinsic safety and explosion prevention is 51 Ω while maintaining the receiving sensitivity.

Reference is made to the measurement value of the communicable distance between the detection apparatus 10 and the portable terminal 6 and the communication result in the second embodiment of fig. 5. When the center of the antenna 64 is 0mm, y is 0mm, and z is 0mm on the upper surfaces of the lid 41 and the window member 50 of the second partition 40, the communicable distance in the z direction between the detection device 10 and the portable terminal 6 and the communication result are measured. As shown in the figure, when the portable terminal 6 is located at the center of the antenna 64, the communicable distance is longest and communication is possible. Even when the portable terminal 6 is offset in the x direction and the y direction, communication can be performed despite the short communicable distance.

As described above, the other one of the zener diodes Z11, Z12 and the other one of Z21, Z22 of the first and

second limiter circuits

67 and 68 in the second embodiment are not used as the voltage limiting elements but are used for redundancy. Therefore, when the parasitic capacitance is sufficiently small, the other of the zener diodes Z11 and Z12 and the other of Z21 and Z22 are not included in the first and

second limiter circuits

67 and 68 in action. Therefore, the communicable distance and the communication result shown in fig. 5 can also be applied to the first embodiment.

In addition, in the first embodiment, the antenna circuit 66, the first limiter circuit 67, and the second limiter circuit 68 include the wiring section area, and the wiring widths of the wirings L1 and L2 in the wiring area may be 2mm or more. For example, in the first embodiment, the wiring section area LA1 is provided between the capacitor C of the antenna circuit 66 and the zener diode Z11 of the first limiter circuit 67 on the auxiliary substrate 60, and the wiring section area LA2 is provided between the capacitor C of the antenna circuit 66 and the zener diode Z21 of the second limiter circuit 68. Therefore, it can be considered that the wiring between the capacitor C of the antenna circuit 66 and the zener diodes Z11 and Z21 of the first and

second limiter circuits

67 and 68 is not disconnected for the requirement of intrinsic safety explosion prevention. Thus, the value of the voltage applied to the capacitor C is determined, and the capacitance can be evaluated.

Further, in the second embodiment, the antenna circuit 66, the first limiter circuit 67, and the second limiter circuit 68 include a wiring section area in which the wiring widths of the wirings L1 and L2 may be 2mm or more. For example, in the second embodiment, the wiring section area LA1 is provided between the capacitor C of the antenna circuit 66 and the zener diodes Z11 and Z12 of the first limiter circuit 67 on the auxiliary substrate 60, and the wiring section area LA2 is provided between the capacitor C of the antenna circuit 66 and the zener diodes Z21, Z22 of the second limiter circuit 68. Therefore, it can be considered that the wiring between the capacitor C of the antenna circuit 66 and the zener diodes Z11, Z12 and Z21, Z22 of the first and

second limiter circuits

67 and 68 is not cut for the requirement of intrinsic safety explosion prevention. Thus, the value of the voltage applied to the capacitor C is determined, and the capacitance can be evaluated.

The present invention described above has the following effects.

The receiving circuit 65 of the detection apparatus 10 includes: an antenna circuit 66 configured by the antenna 64 and the capacitor C; first and

second limiter circuits

67 and 68 constituted by zener diodes Z11 and Z21 and resistors R1 and R2; and an electronic circuit 63. One end of the antenna circuit 66 and one end of the electronic circuit 63 are connected via a first limiter circuit 67, and the other end of the antenna circuit 66 and the other end of the electronic circuit 63 are connected via a second limiter circuit 68. Thereby, a protection level to which the concept of counting failures is not applied can be satisfied, and high intrinsically safe explosion-proof performance can be provided.

The first and

second limiter circuits

67 and 68 of the reception circuit 65 may connect in parallel zener diodes Z11, Z12 and zener diodes Z21, Z22. Accordingly, all protection levels can be satisfied, and higher intrinsically safe explosion-proof performance can be provided.

The first and

second limiter circuits

67 and 68 of the reception circuit 65 can set the parasitic capacitances of the zener diodes Z11, Z12, Z21, and Z22 to 30pF or less, and can make the resistance values of the resistors R1 and R2 51 Ω. Accordingly, it is possible to provide both the receiving sensitivity and the high intrinsically safe explosion-proof performance.

The antenna circuit 66 of the reception circuit 65 and the first and

second limiter circuits

67 and 68 include a wiring section area where the wiring widths of the wirings L1 and L2 may be 2mm or more. Accordingly, it is considered that the wiring between the capacitor C and the zener diodes Z11, Z12, Z21, and Z22 is not cut. Accordingly, it is possible to evaluate whether the capacitance value is within the upper limit, and it is possible to provide high intrinsically safe explosion-proof performance.

Although the communication device of the present invention has been described as an example of the case where it is used in a petrochemical plant, it may be used in other dangerous places. Examples of dangerous places include liquefied petroleum gas filling stations, tunnel excavation sites, thermal power plants, paint plants, and the like.

In addition, the communication device has been described taking the detection device as an example, but the communication device is not limited to the detection device, and may be applied to other devices as long as the device performs wireless communication with a device outside the housing.

That is, the present invention is not limited to the above-described embodiments as long as the functions and effects of the present invention are achieved. For example, the window member and the auxiliary substrate may be provided integrally with the second separator, and the control substrate may be fixed to the first separator.

Possibility of industrial application

The receiving circuit and the communication device of the present invention are suitable for use as a detection device used in a petrochemical plant.

Description of reference numerals:

reference numeral 6 denotes a portable terminal (communication device);

reference numeral 10 denotes a detection device (communication device);

reference numeral 11 denotes a housing;

reference numeral 14 denotes a control substrate;

reference numeral 30 denotes a1 st divided body;

reference numeral 40 denotes a2 nd divided body;

reference numeral 41 denotes a cover portion;

reference numeral 50 denotes a window member;

reference numeral 60 denotes an auxiliary substrate;

reference numeral 61 denotes a flexible printed circuit substrate;

reference numeral 63 denotes an electronic circuit;

reference numeral 64 denotes an antenna;

reference numeral 65 denotes a receiver circuit;

reference numeral 66 denotes an antenna circuit

Reference numerals

67, 68 denote clip circuits;

reference numeral 80 denotes a battery module;

symbol C represents a capacitor;

symbol DA represents a hazardous location;

symbols L1 and L2 denote wirings;

symbols LA1 and LA2 denote wiring portion regions

Symbols R1 and R2 represent resistors (current-limiting elements);

symbols Z11, Z12, Z21, Z22 denote zener diodes (voltage limiting elements).

Claims

1. A receiving circuit, characterized in that the receiving circuit comprises:

an antenna circuit composed of an antenna and a capacitor,

first and second limiter circuits formed of a zener diode and a resistor;

an electronic circuit, wherein,

one end of the antenna circuit and one end of the electronic circuit are connected via the first limiter circuit, the other end of the antenna circuit and the other end of the electronic circuit are connected via the second limiter circuit,

2. The receiver circuit according to claim 1, wherein two of said zener diodes are connected in parallel in the first and second limiter circuits.

3. The receiver circuit according to any one of claims 1 and 2, wherein in the first and second limiting circuits, a parasitic capacitance of the zener diode is 30pF or less, and a resistance value of the resistor is 51 Ω.

4. The receiving circuit according to any one of claims 1 to 3, wherein the antenna circuit and the first and second limiter circuits include a wiring region;

the wiring regions are connected with a wiring width of 2mm or more.

5. A communication device, characterized in that it comprises a receiving circuit according to any one of claims 1 to 4.