JP2002008182A - Optical field bus equipment and optical field bus system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide optical field bus equipment capable of eliminating the need of replacement of a battery without impairing the characteristics thereof and an optical field bus system using the optical field bus equipment. SOLUTION: This optical field bus equipment is connected to optical fibers 3A and 5A as transmission media to exchange optical signals so as to communicate with a host control device 11. The equipment comprises a power circuit 25 receiving a power supply from an external power supply line 61, a secondary battery 20, a battery charging circuit 28 for charging the secondary battery 20 from the power circuit 25, a low voltage detection means 27 for detecting a voltage drop of the power circuit 25, and a power switching circuit 29 for switching the power supply to the internal circuit of the optical field bus equipment 2 from the power supply from the external power supply line 61 to the power supply from a secondary battery circuit system. Normally, the device is operated on the power supply from the external power supply line 61 and, when the voltage drop detection means 27 detects the voltage drop of the power circuit 25, operated on the power supply from the secondary battery 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrumentation for measuring measured quantities such as flow rate, pressure and temperature in a plant with a field device installed in a field and collectively processing and controlling data in a remote control room. The present invention relates to an optical fieldbus device which is easily applied to a system and is easy to maintain, and an optical fieldbus system using the device.

[0002]

2. Description of the Related Art FIG. 9 is an explanatory diagram showing an example of use of a conventional optical fieldbus device. In FIG. 9, the control room 8
Between the optical fieldbus host control device 11 and the optical fieldbus devices 82 (82A, 82B, 82C, etc.), the trunk optical fiber 3A, the optical star coupler 4A, and the branch optical fiber 5A.
And are connected through. In FIG. 10, the optical fieldbus device 82 includes an electric / optical (E /
O) an optical unit 21 including a converter and an optical / electrical (O / E) converter, a modem 22, a central processing unit (CPU) 23,
In the illustrated example, a sensor unit 24 that detects field data,
And a primary battery 30 for operating these components.

In such a configuration, data detected by the sensor unit 24 is processed by a central processing unit (CPU) 23 and transmitted to a modem.
22 converts the parallel data into serial data in a format in accordance with the transmission protocol, and the optical unit 21 converts the electrical serial data 0,1 signal into optical 0,1 signal,
Data is transmitted to the host controller 11 via 5A, the optical star coupler 4A, and the trunk optical fiber 3A. Conversely, various commands and data are transmitted from the host control device 11 to the optical fieldbus device 82, and the optical / electrical (O
/ E) The converter converts the optical signal to electrical 0,1 signal and the modem
The data is converted into parallel data in a predetermined format at 22 and is taken into a central processing unit (CPU) 23.

The central processing unit (CPU) 23 can perform a predetermined control operation based on the received data, for example, changing the range of a sensor or setting parameters. Further, although the illustrated example is displayed by the sensor unit 24, this part can be used as, for example, an operation terminal or a local controller. In such an optical fieldbus device, the optical fiber buses 3A and 5A are used.
Since it is difficult to supply sufficient energy for driving a terminal such as 82, a primary battery 30 is used as a drive power supply for this terminal in the prior art. Due to the limitation of the battery capacity of the primary battery 30, once every several years or
When the amount of energy of the battery 30 was reduced and an alarm was notified, maintenance work such as replacing the battery as needed was required.

FIG. 11 is an explanatory view showing an example of use of a conventional electric field bus device 92. As shown in FIG. In FIG.
Electric fieldbus host control device 91 placed in control room 9
The electric field bus devices 92 (92A, 92B, 92C,...) Are connected via a two-wire electric bus 93. The terminating resistor 94 matches the propagation characteristic impedance of the two-wire electric bus 93, prevents reflection of the electric pulse signal, and secures the pulse transmission characteristic. This two-wire electric bus
Reference numeral 93 denotes a type in which a communication signal is superimposed on a DC voltage, and an electric fieldbus device 92 has a two-wire system without a storage function such as a battery 30 inside the device like the optical fieldbus device 82. It operates only with energy from a DC power supply supplied from outside the device via the electric bus 93.

[0006]

As described above, in the prior art optical fieldbus device, once every several years, or
It is necessary to replace the battery every time the energy amount of the primary battery is reduced, which is troublesome and requires maintenance cost for battery replacement. Although electric fieldbus devices do not require battery replacement, they supply energy to multiple devices through a common wire (bus), so power supplies are not independent. For example, a single device or branch line When a power supply system failure such as a short-circuit failure occurs, there is a problem that devices of the same system cannot operate simultaneously.

The present invention is directed to an optical fieldbus device which does not need to replace batteries without impairing the characteristics of the optical fieldbus device, such as noise resistance, lightning resistance, insulation and independence, and an optical device using this device. A field bus system is provided.

[0008]

According to the present invention, there is provided an optical field bus device which uses an optical fiber as a transmission medium, is connected to the transmission medium, transmits / receives an optical signal, and communicates with a higher-level control device. , A power supply circuit receiving power supply from an external power supply line, a secondary battery, a secondary battery charging circuit for charging the secondary battery from the power supply circuit, a low voltage detecting means for detecting a voltage drop of the power supply circuit, And a power supply switching circuit for switching power supply to the internal circuit of the fieldbus device from a power supply circuit system operated by power supply from an external power supply line to a secondary battery circuit system.

With this configuration, the power supply circuit is normally operated by the power supply from the external power supply line, and can be operated by the power supply from the secondary battery when the low voltage detecting means detects a voltage drop of the power supply circuit. . Further, the optical fieldbus device can include a notifying unit that notifies the higher-level control device of the switching of the power supply circuit system by an optical signal when the low voltage detection unit detects a voltage drop of the power supply circuit.

With this configuration, the operator in the control room can know that some abnormality has occurred in the power supply circuit system of the optical fieldbus device, and can investigate the cause and take appropriate measures. . The optical fieldbus system using this optical fieldbus device can normally perform data transmission by an optical signal using the switched secondary battery circuit system, so that the above-described power supply system abnormality occurs. However, the operation can be continued without affecting the optical fieldbus system.

An optical field bus system using the optical field bus device includes an optical field bus host control device provided in a control room, a power supply device, and an optical field bus device provided in the field (hereinafter, bus). An optical star coupler that branches and couples an optical signal between a higher-level control device and a bus device; a main optical fiber that transmits an optical signal between the higher-level control device and the optical star coupler; A branch optical fiber for transmitting an optical signal between the optical star coupler and the bus device, and an external power supply line for supplying power from the power supply device to the bus device can be provided.

Further, the optical fieldbus system includes an optical fieldbus higher-level control device provided in a control room, a power supply device, an optical fieldbus device provided in a field, and a higher-level control device and a bus device. An optical star coupler for branching / coupling optical signals, a trunk composite cable composed of an optical fiber and a power supply line for transmitting and supplying an optical signal between the host controller and the optical star coupler, an optical star coupler and a bus device And a branch line composite cable composed of an optical fiber for supplying an optical signal and a power supply therebetween and a power supply line.

Further, the optical fieldbus system includes an optical fieldbus host control device provided in a control room, an optical fieldbus device provided in a field, and a light signal between the host control device and the bus device. · Optical star couplers that combine and receive power from an external power supply and supply individual power to each bus device, trunk optical fibers that transmit optical signals between the host control device and the optical star coupler, and optical star couplers It can be configured to include an optical fiber for supplying an optical signal and power to the bus device, and a branch line composite cable including a power supply line.

In the optical fieldbus system, the power supply device disposed in the control room is an energy supply for limiting the output energy supplied to the power supply output end to a voltage or current value specified in advance by an intrinsically safe explosion-proof standard. A barrier can be provided. With this configuration, an optical fieldbus system that satisfies the intrinsically safe explosion-proof standard can be configured.

The power supply circuit for receiving power supply from the external power supply line of the optical field bus device includes an insulating transformer or an inverter and an insulating transformer, and insulates between the external power supply line and the internal circuit power supply. be able to. With this configuration, it is possible to insulate between the external power supply line and the internal circuit power supply of the optical fieldbus device. In particular, when a part of the electrode of the sensor unit is structurally connected to the ground line, it is possible to improve the noise resistance by cutting off the circuit.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a main part of an optical field bus system according to an embodiment of the present invention, FIG. 2 is a block diagram of a main part of another optical field bus system, and FIG. FIG. 4 is a block diagram of an optical fieldbus device, FIG. 5 is a cross-sectional view of a composite cable,
6 is a block diagram of a main part of an optical star coupler, FIG. 7 is a block diagram of a zener barrier by intrinsically safe explosion protection, FIG. 8 is an insulated power supply circuit diagram, and the same members corresponding to FIGS. It is attached. (Embodiment 1) In FIGS. 1 and 4, an optical fieldbus device 2 according to the present invention uses an optical fiber (3A), 5A as a transmission medium, is connected to the transmission medium, transmits and receives optical signals, and It communicates with the external power supply line.
61, (5C) Power supply circuit 25 receiving power supply and secondary battery
20, a battery charging circuit 28 for charging the secondary battery 20 from the power supply circuit 25, a low voltage detecting means 27 for detecting a drop in the output voltage of the power supply circuit 25, and an external power supply to the internal circuit of the optical fieldbus device 2. Power supply circuit operated by power supply from power supply line 61, (5C)
And a power supply switching circuit 26 for controlling switching from the 25 system to the secondary battery circuit 20 system.

With this configuration, the external power supply line 6 is normally
When the low-voltage detecting means 27 detects the voltage drop of the power supply circuit 25, it operates with the power supply from 1, (5C).
It can be operated with the power supply from. Also, in this optical fieldbus device 2, the low voltage detecting means 27
When detecting the voltage drop of 25, a notification unit that notifies the higher-level control device 11 of the switching of the power supply circuit 25 by an optical signal can be provided.

With this configuration, the operator in the control room 1 can know that any abnormality has occurred in the power supply circuit 25 of the optical fieldbus device 2, and investigate the cause and take appropriate measures. be able to. Note that the optical fieldbus system using the optical fieldbus device 2 has a switched secondary battery circuit system 20.
Since data transmission by optical signals can be performed normally, even if an abnormality occurs in the power supply system (6), 61, or 25 described above, operation can be continued without affecting the optical fieldbus system. it can. (Embodiment 2) In FIG. 1, an optical fieldbus system using an optical fieldbus device 2 is provided in an optical fieldbus host control device 11 provided in a control room 1, a power supply device 6, and a field. An optical fieldbus device 2, an optical star coupler 4 for branching / coupling an optical signal between the upper control device 11 and the bus device 2, and a trunk line for transmitting an optical signal between the upper control device 11 and the optical star coupler 4 An optical fiber 3 (3A), a branch optical fiber 5 (5A) for transmitting an optical signal between the optical star coupler 4 and the bus device 2, and an external power supply line 61 for supplying power from the power supply device 6 to the bus device 2; And can be configured.

With such a configuration, the optical fieldbus device 2 always operates with the power supply from the external power supply line 61, (5C), and when the low voltage detecting means 27 detects a voltage drop of the power supply circuit 25, It can operate with the power supply from the secondary battery 20. In particular, when the low voltage detection means 27 detects a voltage drop of the power supply circuit 25, the operator in the control room 1 notifies the host control device 11 of the switching of the power supply circuit 25 system by an optical signal, thereby Since it is possible to know that some abnormality has occurred in the power supply circuit 25 of the optical fieldbus device 2, it is possible to investigate the cause and take appropriate measures.

[0020]

(Embodiment 1) In FIG. 1, an optical fieldbus host device 11 placed in a control room 1 includes a trunk optical fiber 3A,
It is connected to the optical fieldbus device 2 (2A, 2B, 3C,...) Via the optical star coupler 4A and the branch optical fiber 5A, and communicates using optical signals as transmission means. Further, a power supply from the power supply device 6 is connected to the optical fieldbus device 2 via an external power supply line 61, and the optical fieldbus device 2 always operates with energy supplied via the external power supply line 61. . Here, when the power supply voltage supplied from the power supply device 6 is a DC voltage such as 24 V DC, for example, the external power supply line 61 may use the two-wire electric bus 93 shown in FIG. It is possible. If the optical fieldbus device 2 can operate by receiving a wide range of power from a DC voltage such as DC 24 V to an AC voltage AC 100 V, for example, the commercial power supply wiring system can be used as the external power supply line 61. it can.

Next, an optical fieldbus device 2 according to the present invention will be described. In FIG. 4, the optical fieldbus device 2
In the illustrated example, an information processing portion as the optical fieldbus device 2 that performs information processing of the sensor signals illustrated by the member numbers 21 to 24 and communicates with the host control device 11 by optical signals,
The member number that supplies power to the internal circuit of this information processing part
20, 25-29.

This information processing portion is the same as the content described in the section of the prior art in FIG. 10 except that the driving power supply circuit uses the primary battery 30. That is, electricity / light (E
An optical unit 21 including a / O) converter and an optical / electrical (O / E) converter, a modem 22, a central processing unit (CPU) 23,
In the illustrated example, a sensor unit 24 that detects field data,
The power supply circuit section 20, 25 to 29 for operating these sections is constituted.

In such a configuration, the data detected by the sensor unit 24 is processed by the central processing unit (CPU) 23,
22 converts the parallel data of the CPU 23 into electrical serial data (0, 1 signals) in a format in accordance with the transmission
This converts the electricity (0,1 signal) into optical (0,1 signal) and transmits data to the host controller 11 via the branch optical fiber 5A, optical star coupler 4A, and trunk optical fiber 3A. Is done. Conversely, various commands and data are transmitted from the higher-level control device 11 to the optical fieldbus device 82, and the optical unit
21 optical / electrical (O / E) converters convert optical signals into electrical (0,1 signals)
The data is converted into parallel data in a predetermined format by the modem 22, and is taken into the central processing unit (CPU) 23.

The central processing unit (CPU) 23 can perform a predetermined control operation based on the received data, for example, changing the range of a sensor or setting parameters. Further, although the illustrated example is displayed by the sensor unit 24, this part can be used as, for example, an operation terminal or a local controller. The energy used as the operating power for the optical fieldbus device 2 is supplied from an external power supply line 61 (see FIG.
Supplied from 1), (5C / Figs. 2, 3). This external feeder 61 (5C)
Is connected to a power supply circuit 25.The power supply circuit 25 receives a supply power supply voltage such as DC24V or AC100V, for example.
While supplying power energy as a voltage suitable for the operation of the internal circuit, sneak circuits through noise elimination and grounding circuits, especially when some electrodes of the sensor unit are structurally connected to the ground line In order to block the sneaking around, a function such as insulation of the power supply circuit 25 can be provided as needed.

FIG. 8 shows an embodiment of the power supply circuit 25. For example, in FIG. 8A, when an AC power supply of 100 V is supplied, this AC voltage is rectified by a rectifier REC1.
Smoothing with capacitance C1, pulse width modulation with switching regulator SWR, insulation with transformer PT, rectification (REC2), smoothing (C
2) Obtain a DC output voltage and feed back this DC output voltage to the switching regulator SWR to control the voltage required by the internal circuit.As a result, the DC power supply voltage such as DC24V can be controlled to AC100V etc. AC power supply can be adapted to a wide range of power supplies.

For example, the insulation of the DC power supply of 24 VDC may be performed by the switching regulator SWR described above, or alternatively, the high frequency pulse signal may be isolated by the inverter circuit in the circuit shown in FIG. It is also possible to obtain a DC output voltage by insulating with a transformer PT, rectifying (REC2) and smoothing (C2). Returning to FIG. 4, the internal circuit of the optical fieldbus device 2 inputs the output of the power supply circuit 25 to the power supply switching circuit 29 via the diode 26A, and normally outputs the power supply switching circuit 29 to the output of the power supply circuit 25. By selecting and switching so that the internal circuit is driven by
It can be operated with the power supply from the external power supply line 61 (5C).

The output of the power supply circuit 25 is also connected to a secondary battery charging circuit 28. Normally, when electric energy is supplied from the power supply circuit 25, the secondary battery 20 is connected via a diode 26B. And energy is stored in the secondary battery 20. Since the secondary battery charging circuit 28 can use a dedicated IC or the like and is a well-known technology, the description thereof is omitted here. Here, for example, when a failure such as a short circuit or disconnection occurs in the power supply circuit 25 itself or the external power supply line 61 (5C), the energy stored in the secondary battery 20 is discharged backward to the outside when the diodes 26A and 26B are used. It is to prevent that.

The low-voltage detecting means 27 uses, for example, a comparator (not shown) for comparing a reference voltage for monitoring a voltage with an output voltage of the power supply circuit 25 to be monitored. Power supply circuit
When the supply voltage from 25 falls below a predetermined voltage, the signal output to power supply switching circuit 29 and central processing unit (CPU) 23 is inverted. By the inversion operation of the output signal of the low voltage detecting means 27, the power supply switching circuit 29 switches the power supply to the internal circuit from the energy directly supplied to the power supply circuit 25 to the energy stored in the secondary battery 20. Thus, power supply energy can be continuously supplied.

When the output signal of the low voltage detecting means 27 is inverted, the central processing unit (CPU) 23 detects that the power supply to the internal circuit has been switched from the external power supply line 61 (5C) to the secondary battery 20. can do. The central processing unit (CPU) 23 detects the switching of the power supply, thereby
And output to the branch optical fiber 5A as an optical signal conforming to a transmission protocol defined as an optical fieldbus system via an electric / optical (E / O) converter of the optical unit 21,
It is possible to notify the optical fieldbus host control device 11 that a failure has occurred in the power supply system. (Embodiment 2) An optical fieldbus system using an optical fieldbus device 2 will be described as another embodiment of the present invention with reference to FIGS.

In FIG. 2, an optical fieldbus host control device 11 provided in the control room 1, a power supply 6, and an optical fieldbus device 2 (2A, 2B, 2C.
.), An optical star coupler 4 (4B) for branching / coupling an optical signal between the host control device 11 and the bus device 2, and a host control device
An optical fiber signal between the optical star coupler 4B and the bus device 2, and a trunk composite cable 3B composed of an optical fiber 3A and a power supply line 3C for transmitting an optical signal and supplying power between the optical star coupler 11B and the optical star coupler 4B. Optical fiber 5A to supply power and power supply line 5C
And a branch line composite cable 5B.

The difference from FIG. 1 is that the wiring part of the external power supply line 61 in FIG. 1 is composed of the trunk composite cable 3B and the branch composite cable 5B in FIG. 2, and the optical fibers 3A, 5A and the power supply line 3 are connected.
C and 5C are integrated. With this configuration, since the optical fibers 3A, 5A and the feeder lines 3C, 5C are integrated by the composite cables 3B, 5B, the cable routing is integrated, and the cable laying and inspection of the cables are performed by an external power supply. It can be handled at the same level as the conventional technology without the electric wire 61 (5C).

In FIG. 5, the illustrated example is a cross-sectional view of a commercially available metal composite cable in which a metal communication line is combined with a control line or a communication line in an optical fiber cable. In FIG. 5A, an optical fiber core wire 51 and a communication wire 52 are provided on an outer peripheral portion of a tension member 53 for imparting mechanical strength of a composite cable, and a buffer layer 54, a presser winding 55, and a sheath 56 are connected. An example of a layered composite cable provided is illustrated. FIG. 5B shows the tension member of the composite cable.
Optical fiber unit 51A and communication line 52
A illustrates an example of a unit-type composite cable provided with A and including a presser winding 55 and a sheath 56. In addition, FIG.
The optical fiber core 51 is provided on an outer peripheral portion of a tension member 53 of the composite cable via a spacer 57, a communication line 52A is provided on the outer peripheral portion, and a holding coil 55 and a sheath 56 are provided. An example of a spacer type composite cable is illustrated.

In FIG. 3, an optical fieldbus host control device 11 provided in the control room 1 and an optical fieldbus device 2 (2A, 2B, 2C,...) Provided in the field,
An optical star coupler 4C that branches and combines an optical signal between the host control device 11 and the bus device 2 and receives power from an external power source and supplies individual power to each bus device 2;
A main line optical fiber 3A for transmitting an optical signal between the optical star coupler 4C and a branch line composite comprising an optical fiber 5A for supplying an optical signal and power between the optical star coupler 4C and the bus device 2 and a power supply line 5C. And a cable 5B.

With this configuration, when supplying power to the optical fieldbus device 2, electric energy is supplied from the external power supply 63 to the optical star coupler 4C, for example, from a commercial power supply of AC100 or a DC power supply of DC24V. Optical star coupler 4C
Using the electric energy supplied from the external power supply 63,
For example, in the case of a commercial power supply of AC100, the voltage is insulated and stepped down by a transformer, rectified and smoothed to form a voltage (for example, 24 V DC) suitable for the optical fieldbus device 2, and each optical fieldbus device 2 is individually supplied with power. Can be. This optical star coupler
The power supply circuit unit 64 incorporated in the 4C includes the above-described simple insulated DC circuit or the power supply circuit 25 described in the optical fieldbus device 2 shown in FIG. A similar circuit can be used.

In FIG. 6, the optical star coupler 4 (4A, 4B, 4
C) is a mixing rod 41, an optical fiber (42A-42I) for transmitting an optical signal to an optical terminal (43A-43I), and an electric terminal (45A-
45I), the power supply circuit section 64 described above, and the wiring 44 for distributing the voltage from the power supply circuit section 64. In such a configuration, the mixing rod 41 of the illustrated example uses a reflection type optical waveguide. For example, an optical signal incident from the optical terminal 43A is incident on one end face of the mixing rod 41 via the optical fiber 42A, and The light propagates through 41, is reflected on the other end face, and returns to one end face. When the length of the mixing rod 41 is properly selected, the optical signal returning to the one end face is almost uniformly dispersed, the optical signal is evenly distributed to each optical fiber (42A to 42I), and the optical terminal (43A ~
43I). If the other end face of the mixing rod 41 is formed of, for example, a diffuse reflection mirror, the length of the mixing rod 41 can be further reduced, and the optical signal incident from any of the optical terminals (43A to 43I) can be uniformly reduced. The light can be dispersed and output from each of the optical terminals (43A to 43I). Further, the mixing rod 41 can be configured using a transmission optical waveguide in addition to the reflection optical waveguide. Now, assuming that the optical terminal 43A is an optical terminal for connecting to the host control device 11, the other optical terminals (43B to 43I) can be optical terminals for connecting to the optical fieldbus device 2 (2A to 2H).

The electric terminal 45A is used as a power receiving terminal of a power supply from the external power supply 63. For example, when a commercial power supply is received, a power supply circuit section 64 for converting to a voltage suitable for the power supply of the optical fieldbus device 2 is connected. This output voltage is
Is distributed to each of the electric terminals (45B to 45I). In addition, electric terminal
When the input voltage to the 45A is, for example, 24 VDC and the power of the optical fieldbus device 2 is also 24 VDC, the power supply circuit section 64 is naturally provided.
Are omitted, and power is directly distributed to the respective electric terminals (45B to 45I) by the wiring 44.

In the optical field bus system using the optical star coupler 4C according to FIG.
In an area where the optical fieldbus device 2 is installed at a distance from the remote location and separated by Km, and where the external power supply line 61 of the system shown in FIG. 1 is easily affected by lightning strikes, the optical star bus shown in FIG. Using an optical fieldbus system using a coupler 4C, receiving power from commercial power supply from a place relatively close to the field, and opening a power supply for this commercial power supply during a lightning strike, avoiding the effects of lightning strikes, and Communication with the control device 11 is performed by receiving power from the secondary battery 20 built in the optical fieldbus device 2 and performing communication control by an optical signal, thereby continuing the operation of the system without interrupting the system. be able to. (Embodiment 3) The power supply device 6 provided in the control room 1 applies output energy supplied to the power supply output terminals (45B to 45I) of the optical star couplers 4A and 4B to a voltage determined in advance by an intrinsically safe explosion-proof standard. An energy barrier 62 for limiting the current value to a current value or less can be provided.

When electric equipment is installed in a place where the explosive hazardous gas may stagnate in the field installation environment, explosion-proof measures are taken. Generally, in the field of measurement and control, in particular, devices installed in a field are configured to operate with low energy. Therefore, in such a case, the intrinsically safe explosion-proof system is applied, and the equipment installed in the field uses intrinsically safe explosion-proof equipment, and the power supply device 6 installed in a safe place and the bus equipment 2A- The power supply to 2C
(Generally a zener barrier).

An example of such an energy barrier 62 is shown in FIG. In FIG. 7, the energy barrier 62 includes a fuse F, at least two Zener diodes 67,
And a current limiting circuit 65. Intrinsically safe explosion-proof grounding is performed on the 0V circuit side. The fuse F is, for example, AC55
Even if a voltage of 0 V or DC 430 V is applied, use a cooperative member so that the fuse F is disconnected first and the Zener diode 67 is not blown.In such a state, the current limiting circuit 65 To limit the energy to dangerous places.

According to the present invention, since each optical fieldbus device individually has a power supply for the secondary battery, a charging circuit for the secondary battery, and a switching circuit for the power supply system,
The independence of the power supply is high as in the case of the optical fieldbus device receiving power supply from the primary battery in the prior art. In the present invention,
Even in the event of a breakage in the trunk optical fiber, if a device having a master function, for example, a local controller is arranged on the optical fieldbus device side and the system is configured, the PID control operation can be performed only by the fieldbus device. It is possible, and control can be performed without intervention of a higher-level control device, so that so-called independent distributed control can be stably constructed.

In an electric field bus system in which power is supplied and communication is performed from a common electric wire, the electric field bus system can be independently dispersed in a normal operation state. When the error occurs, a plurality of devices cannot operate at the same time. Therefore, even if a device having a master function exists on the field bus device side, the device cannot perform the function. In this sense,
The optical fieldbus system of the present invention can construct a system with high autonomous dispersion.

In the electric field bus system, since the communication line and the power supply line are common, the communication system and the power supply system are not usually duplicated. In addition, our optical fieldbus equipment can easily duplicate the communication line (main line), but basically operates with only one primary battery. If the battery replacement is delayed for some reason, in the worst case, the operation may be stopped.

That is, in any case, the power supply is not duplicated. In the present invention, in other words, the above-mentioned autonomous decentralization is realized by duplicating the power supply, and enabling the construction of a higher-reliability control system with an optical field bus device and an optical field bus device using this device. The ability to provide a bus system.

[0044]

According to the present invention, by providing the external power supply line, the battery charging circuit, the secondary battery, and the low voltage detecting means in the optical field bus device, the energy from the external power supply line is always provided. It operates by power supply, and when the supply of energy from the external power supply line is no longer available, it operates by switching to a secondary battery as a power supply, so it has an optical field such as noise resistance, lightning resistance, insulation, autonomous dispersion and independence It is possible to realize an optical fieldbus device that does not need to replace batteries without impairing the features of the bus device and an optical fieldbus system using this device.

The optical fieldbus device can notify the host control device that it is operating on a battery, so that the operator can immediately know that a failure has occurred in the power supply system. The operation can be continued as a system until the power supply system is restored, and a highly reliable instrumentation system can be constructed. Also,
When used in place of an electric field bus device, the already laid two-wire electric bus line can be used as a power line as it is, so there is no need to lay a new power line and it is economical.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an optical fieldbus system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of another optical field bus system.

FIG. 3 is a configuration diagram of a main part of another optical field bus system.

FIG. 4 is a block diagram of an optical fieldbus terminal.

FIG. 5 is a sectional view of a composite cable

FIG. 6 is a configuration diagram of a main part of an optical star coupler.

FIG. 7 is a block diagram of an intrinsically safe explosion-proof zener barrier.

FIG. 8 is a circuit diagram of an insulated power supply, (A) is a circuit diagram of a switching regulator, and (B) is a circuit diagram of an inverter.

FIG. 9 is a configuration diagram of a main part of an optical fieldbus system according to the related art.

FIG. 10 is a block diagram of an optical fieldbus terminal.

FIG. 11 is a configuration diagram of a main part of an electric field bus system.

[Explanation of symbols]

 1, 8, 9 Control room 11 High-level control device for optical field bus 2, 2A, 2B, 2C Optical field bus device 20 Secondary battery 21 Optical unit 22 Modem unit 23 Central processing unit 24 Sensor unit 25 Power supply circuit 26A, 26B Diode 27 Low voltage detection means 28 Secondary battery charging circuit 29 Power supply switching circuit 3 Trunk cable 3A Trunk optical fiber 3B Trunk composite cable 3C, 5C Power supply line 30 Primary battery 4,4A, 4B, 4C Optical star coupler 41 Mixing rod 42A to 42I Optical fiber 43A to 43I Optical terminal 44 Wiring 45A to 45I Electric terminal 5 Branch cable 5A Branch optical fiber 5B Branch cable composite cable 51,51A Optical fiber core 52,52A Communication line 53 Tension member 54 Buffer layer 55 Presser winding 56 Sheath 57 Spacer 6 Power supply 61 External power supply line 62 Zener barrier 63 External power supply 64 Power supply circuit 65 Current limiting circuit 67 Zener diode F Fuse PT Transformer SWR Switching regulator INV Inverter REC1, REC2 Rectifier circuit C1, C2 Capacity 91 Electric fieldbus host control device 92 Electric fieldbus device 93 2-wire electric bus 94 Terminating resistor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F073 AA19 AB01 BB06 BC04 CC03 CC07 DD06 EE12 EF09 FG01 FG02 FH02 FH17 2H001 BB01 DD04 FF02 MM08 5G369 AA16 BA08 EA04

Claims (7)

[Claims] An optical field bus device connected to an optical fiber as a transmission medium for transmitting and receiving an optical signal to communicate with a higher-level control device, comprising: a power supply circuit for receiving power supply from an external power supply line; A secondary battery, a secondary battery charging circuit for charging the secondary battery from the power supply circuit, a low voltage detecting means for detecting a voltage drop of the power supply circuit,
A power supply switching circuit for switching power supply to the internal circuit of the optical field bus device from a power supply circuit system operated by power supply from an external power supply line to a secondary battery circuit system, and always supplies power from the external power supply line. And an optical field bus device which operates with a power supply from a secondary battery when the low voltage detecting means detects a voltage drop of the power supply circuit. 2. The optical fieldbus device according to claim 1, wherein when the low voltage detecting means detects a voltage drop of the power supply circuit,
An optical fieldbus device comprising: a notifying unit that notifies a higher-level control device that the power supply circuit system has been switched by an optical signal. 3. An optical fieldbus system using the optical fieldbus device according to claim 1 or 2, wherein: an optical fieldbus host control device provided in a control room;
A power supply device, an optical fieldbus device (hereinafter abbreviated as “bus device”) provided in the field, an optical star coupler for branching / coupling an optical signal between the upper control device and the bus device, and an upper control device. A trunk optical fiber for transmitting an optical signal between the optical star coupler, a branch optical fiber for transmitting an optical signal between the optical star coupler and the bus device, and an external power supply line for supplying power from the power supply device to the bus device And an optical fieldbus system comprising: 4. An optical fieldbus system using the optical fieldbus device according to claim 1 or 2, wherein an optical fieldbus host control device disposed in a control room;
A power supply device, an optical fieldbus device provided in the field, an optical star coupler for branching / coupling an optical signal between the higher-level control device and the bus device, and an optical signal between the higher-level control device and the optical star coupler. A trunk composite cable composed of an optical fiber for supplying transmission and power and a power supply line, and a branch composite cable composed of an optical fiber for supplying an optical signal and power between the optical star coupler and the bus device and a power supply line. An optical field bus system, comprising: 5. An optical fieldbus system using the optical fieldbus device according to claim 1 or 2, wherein: an optical fieldbus higher-level control device provided in a control room;
An optical fieldbus device deployed in the field, and an optical star coupler that branches and combines optical signals between a higher-level control device and the bus device, receives power from an external power supply, and supplies individual power to each bus device. A trunk optical fiber for transmitting an optical signal between the host control device and the optical star coupler, and a branch line composite cable comprising an optical fiber for supplying an optical signal and power between the optical star coupler and the bus device, and a power supply line. An optical field bus system, comprising: 6. The optical fieldbus system according to claim 3, wherein the power supply device disposed in the control room is configured to supply the output energy supplied to the power supply output terminal with intrinsic safety in advance. An optical field bus system, comprising: an energy barrier that limits the voltage and current values to values less than or equal to explosion-proof standards. 7. An optical field bus device according to claim 1, wherein the power supply circuit for receiving power supply from the external power supply line includes an insulation transformer or an inverter and an insulation transformer. An optical field bus device, which insulates between an electric wire and an internal circuit power supply.