JP2019008560A - Process control module - Google Patents

Abstract

To provide a process control module that independently operates as a mass flow controller system, which is intrinsically safe and explosion-proof, in a process control field of treating, for example, an inflammable gas or liquid.SOLUTION: For the purpose of attaining explosion prevention in a process measuring control system for an inflammable fluid installed in a hazardous place, a process control module installed in a non-hazardous place is included. The process control module is configured such that the features of an intrinsically safe and explosion-proof power supply current repeater A, signal converter B, digital indicator regulator C, and power supply circuit D are integrated into a system and intensively unified in a casing 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a process control module which performs an independent operation as a mass flow controller system.

  In general, various transmitters for TIIS international technical guidelines and technical standards certification, TIIS technical standard certification intrinsic safety related equipment and non-intrinsic safety equipment already exist individually.

  Here, TIIS is a certification body that certifies explosion-proof electrical machinery and equipment in Japan, and its official name is an abbreviation for Japan Industrial Safety Technology Association.

  Conventionally, as shown in Patent Document 1, an intrinsically safe explosion-proof power source using a transformer with an incompatibility prevention plate and a limit voltage area in which the output voltage of the intrinsically safe explosion-proof power source is limited in a non-hazardous area are set. A non-intrinsic safety circuit that is installed in the ground and insulated from the ground or grounding point and operates below the limit voltage, and a ground or grounding point that is installed in a hazardous area and operates below the limit voltage in the non-intrinsic safety circuit A power source for the primary side of the intrinsically safe explosion-proof power source when the voltage is equal to or higher than the limit voltage between the isolated intrinsic safety circuit and the power line of the non-intrinsic safety circuit and the case housing the ground or non-intrinsic safety circuit. There is an intrinsically safe explosion-proof device with a device that cuts off.

  In addition, as shown in Patent Document 2, an intrinsically safe explosion-proof device having a bipolar voltage limiting circuit including a semiconductor element having a voltage limiting characteristic between an intrinsically safe circuit and a case grounded to a ground point that accommodates the circuit. The device exists.

Japanese Utility Model Publication No. 60-19493 Japanese Utility Model Publication No. 60-8520

  However, in the past, TIIS international technical guidelines and technical standards certified intrinsically safe products designed for various types of intrinsically safe transmitters, which are modularized by system integration of intrinsically safe equipment and non-intrinsically safe equipment installed in a safe place. Does not exist.

  In addition, as shown in Patent Document 1 and Patent Document 2 described above, customers can use various TIIS international technical guidelines / technical standards certified intrinsically safe explosion-proof transmitters (for example, flow meters and pressure gauges) installed in hazardous locations. In order to construct an intrinsically safe explosion-proof system when adopting, TIIS technical standard certified intrinsic safety-related equipment, non-intrinsic safety equipment, etc. that are installed in a safe place that is compatible with the intrinsically safe equipment installed in the hazardous area are individually used. Prepare and carry out intrinsically safe construction including cables. For this purpose, the customer needs to have knowledge of intrinsically safe explosion-proof instrumentation.

  However, these days, customers have to know that they have the knowledge of intrinsically safe explosion-proof instrumentation and have the ability to perform system design and construction on their own.

  Therefore, it is said that it is intrinsically safe in terms of explosion-proof grade, and because there is a cost advantage, there is a great demand for everyone to adopt it, but the fact is that it is not so much used in Japan.

  Therefore, the present invention was created in view of the existing circumstances as described above, and is modularized by combining various units having predetermined functions including TIIS technical standard certified intrinsic safety related equipment, for example, combustible An object of the present invention is to provide a process control module capable of performing an independent operation as a mass flow controller system for intrinsically safe explosion-proofing in the field of process control for handling gas or liquid.

  The invention of claim 1 according to the present invention has a process control module installed in a non-hazardous area for explosion prevention in a process measurement / control system (for example, a mass flow system) of a flammable fluid installed in a hazardous area. The process control module is an intrinsically safe power for TIIS technical standards that limits the electrical energy supplied to various transmitters under the TIIS international technical guidelines / technical standards certification for process measurement and control systems to below the ignition limit. A signal converter that converts the signal received by the supply current repeater and the power supply current repeater for intrinsically safe explosion-proof from the transmitter (electrical isolation) and outputs a standard signal, and a standard output signal from the signal converter Is used as a measured value and controlled so that the target setting signal matches the measured value. System integration of the individual indicator controller and power supply circuit for supplying power to each of the intrinsically safe explosion-proof power supply current repeater, signal converter, and digital indicator controller and integrating them into the casing. By doing so, the above-mentioned problems were solved.

  According to the process control module of the first aspect, the individual functions of the intrinsically safe explosion-proof power supply current repeater, signal converter, digital indicating controller, and power supply circuit are system-integrated and integrated into the casing. For example, in the process control field that handles flammable gases and liquids, even if the customer does not have sufficient knowledge of intrinsically safe explosion-proof instrumentation, intrinsically safe explosion-proof equipment ( For example, a TIIS certified intrinsically safe explosion-proof system can be constructed by connecting a process control module installed in a safe place with a TIIS international technical guideline certified mass flow meter) with an intrinsically safe cable. The control signal from the digital controller is sent to the TIIS certified explosion-proof type operating terminal (for example, TIIS certified explosion-proof type An independent TIIS certified explosion-proof process control system (a so-called hybrid system of intrinsically safe explosion-proof and explosion-proof explosion-proof) can be easily constructed by outputting to an air-driven control valve equipped with an electro-pneumatic conversion positioner.

  Further, the invention of claim 2 according to the present invention is that the power supply current repeater for intrinsically safe explosion-proof is essential to various transmitters based on TIIS international technical guidelines / technical standard certification for process measurement and control systems (for example, mass flow system). By supplying safety power, receiving a current signal from the transmitter, and limiting the electrical energy supplied from the non-hazardous area to the transmitter in the hazardous area by the barrier circuit below the ignition limit, Solved the problem.

  Since the process control module according to claim 2 is a control module specialized in the loop configuration with various TIIS international technical guidelines / technical standard certified intrinsically safe explosion-proof transmitters, the customer can use the intrinsically safe system on their own. It is possible to solve all the problems that must be done in designing at once.

  Further, the invention of claim 3 according to the present invention is such that the signal converter is electrically isolated as a further safety measure before supplying the signal from the power supply current repeater for intrinsically safe explosion-proof to the circuit of the non-intrinsically safe equipment. In addition, the above-mentioned problem was solved by outputting the standard signal as well as the standard signal.

  According to the process control module of the third aspect, the insulation state between the signal converter and the intrinsically safe power supply current repeater for explosion-proof can be reliably maintained, and the next device (digital indicating controller) can be maintained. It is possible to secure further safety against the output.

  Furthermore, the invention of claim 4 according to the present invention solves the above-described problem by supplying power to each component in the module via the no-fuse breaker.

  According to the process control module of the fourth aspect, the protection of the safety power supply device can be doubled by mounting the fuse on the primary power supply side of the intrinsically safe explosion-proof power supply current repeater.

  Further, according to a fifth aspect of the present invention, the digital indicating controller is provided with a remote local changeover switch function, and the target value setting is changed from the setting from the digital indicating controller to the external setting at the remote switching position. Switching to receive an external setting signal, and adjusting the operation end (for example, flow rate adjustment) in a process measurement / control system (for example, a mass flow system as a process control system) is performed on the external setting signal. The problem described above has been solved.

  According to the process control module of the fifth aspect of the present invention, for example, by externally switching the remote local changeover switch function in the digital indicating controller, an external setting signal from a higher-level device such as DCS, PLC, PC, etc. is digitally indicated. By receiving the signal from the controller, it is possible to remotely control a TIIS certified explosion-proof operating terminal (for example, an air-operated control valve equipped with a TIIS certified explosion-proof electropneumatic positioner) installed in a hazardous area.

  Further, in the invention of claim 6 according to the present invention, the measured value signal is output from the digital indicating controller to a host device including DCS, data logger, PLC, and PC. Solved the problem.

  According to the process control module according to claim 6, an intrinsically safe device (for example, various types of intrinsically safe explosion-proof transmitters) installed in a hazardous area by constantly monitoring the measured value signal from the digital indicating controller in the host device. Explosion-proof measures can be taken in advance.

  The present invention is a combination of various units having a predetermined function including TIIS technical standard certified safety related equipment, modularized, and is essential in the field of process control handling flammable fluids such as explosive gases and liquids. As a process control module that operates independently as a mass flow control system for safety explosion-proof, etc., it is expected to shorten construction time, construction cost and total guarantee as a merit for customers.

  In addition, TIIS certified intrinsically safe explosion-proof equipment and explosion-proof equipment (for example, intrinsically safe explosion-proof flow transmitter and explosion-proof operating terminal) installed in hazardous areas and this process control module installed in safe areas TIIS certified explosion-proof control system (so-called hybrid system of intrinsically safe explosion-proof and explosion-proof) by connecting with intrinsic safety dedicated cable for this safety circuit and general instrumentation cable for explosion-proof type operation end. Can be easily constructed.

It is a block diagram of the circuit block which shows the outline of the example of wiring of the internal apparatus of a process control module in this embodiment. It is a front view which shows the example of a display of the digital indication controller (controller) in a process control module. It is explanatory drawing which shows the connection aspect of the process control module in a non-hazardous area, the mass flow meter and control valve in a hazardous area. It is a front view of a process control module. It is a side view of a process control module.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<Embodiment>
As shown in FIG. 1, the process control module according to the present invention includes a power supply current repeater A (hereinafter referred to as a safety power supply current repeater A), a signal converter B, Individual functions such as the digital indicating controller C and the power supply circuit D are system-integrated and integrated into the casing 1.

  And, for example, TIIS certified international technical guidelines / technical standards certified mass flow meters that measure the flow rate of flammable fluids such as explosive gases and flammable liquids installed in hazardous areas, and TIIS certified explosion-proof explosion proofs that control the flow rate By connecting the air-operated control valve 3 equipped with an electro-pneumatic positioner and the process control system, the electric energy supplied to the mass flow meter is limited to below the ignition limit, and the gas ignition is performed at the explosion-proof operation end. By staying in the case, explosion in a hazardous area is prevented in advance.

  The process control module according to the present invention has a built-in TIIS technical standard certified intrinsic safety holder (genuine power source / current repeater), so it is directly connected to the flow rate transmitter 2A of the technical standard certified regular mass flow meter 2. can do. Therefore, this instrument must be installed in a non-hazardous area.

<Appearance structure of module>
Casing 1 constituting the process control module is a power supply current repeater A, a signal converter B (isolation) for a unified signal 4 to 20 mA, and a digital instruction adjustment by PID control (feedback control) for an external output 4 to 20 mA. Formed in a rectangular box shape incorporating various functions such as C (controller), power supply circuit D, etc., and this casing 1 is attached to a DIN 19-inch rack (or panel), for example, and installed in a non-hazardous area It is a mount type module (see FIGS. 4 and 5).

  The back surface of the casing 1 includes an operation end that can be driven by a control signal of 4 to 20 mA, such as a pneumatically operated diaphragm actuator 5, a TIIS certified explosion-proof electropneumatic positioner 6 and the like, as shown in FIG. A connection terminal 7 that can be connected to the air operated control valve 3 is provided. Moreover, the flow rate transmitter 2A of the certified safety mass flow meter 2 in conformity with the TIIS international standard installed in the hazardous area is passed through the safety cable take-in bracket 8 on the back of the casing 1 with a safety cable. It is directly connected to the main safety side terminals (1) and (2) of the main safety power supply / current repeater A.

  The casing 1 includes a signal converter B that electrically isolates the safety circuit and the non-safety circuit for safety of the circuit. This signal converter B is kept safe for the purpose of making a unified signal. Between the instrument and the digital indicating controller C.

  The specifications of the signal converter B are changed depending on the signal level from the transmitter 2A.

  As shown in FIGS. 2 and 4, a digital indicating controller C is provided on the front surface of the casing 21, and a display unit 11 is provided on the surface thereof.

  As its specific specification, a PV display section 12 for displaying a measured value by a 5-digit 14-segment active color LCD (white / red) 12 and a data display section 13 for displaying a set value by a 5-digit 11-segment color LCD (orange). In addition, a bar graph display unit 14, a group display unit 15, a symbol display unit 16, an event display unit 17, a key navigation display unit 18, a parameter display level unit 19, a status display unit using a 12 segment color LCD (orange and white) 20, a security display unit 21, a ladder operation display unit 22, a second loop display unit 23, and a manual set enter key 24 are provided.

<Circuit configuration inside the module>
As shown in FIG. 1, the main power supply current repeater A includes an AC adapter E for outputting target power from alternating current. The power supply and signal input terminals “1, 2” of this cheap power supply current repeater A are connected to a technical standard certified secure mass flow meter 2 that conforms to the TIIS international standard equipped with a flow rate transmitter 2A. The output signal of the main power supply current repeater A is connected from the terminals “11, 12” to the input signal terminals “1, 4” of the signal converter B.

  The (+) terminal “9” of the signal converter B is connected to the terminal “203” for the measured value (PV value) of the digital indicating controller C, and the (−) terminal “12” of the signal converter B is digitally indicated. It is connected to a terminal “204” for a measurement value (PV value) of the controller C.

  The digital indicating controller C is connected from the terminals “205” and “206” for measurement values (PV values) to the host device of the monitoring center server S, and is connected to terminals “305” and “target values setting (SP value)”. 306 ”is connected to the upper device of the monitoring center server S.

  Terminals “207” and “208” for the control output signal of the digital indicating controller C are connected to the pneumatic control valve 3 which is a TIIS explosion-proof operation end.

  The power supply circuit D has three distribution terminals “A”, “B”, and “C” for outputting target power from an alternating current from a commercial power supply (100 Vac), and the distribution terminal “A” The signal converter B is connected to the (U +) terminal “13” and the (V−) terminal “14”, and the distribution terminal “B” has three terminals “110” for command signals of the digital indicating controller C, “111” and “112” are connected, and the distribution terminal “C” is connected to the AC adapter E through a fuse on the hot line side.

<Functions of module components>
(1) The Honan power supply current repeater A supplies the Honan power supply (+ 24Vdc) to various transmitters (here, shown in FIGS. 1 and 3) of the TIIS international technical guidelines / technical standards certification. The measurement signal from 6 is received. Here, the electric energy supplied from the non-hazardous area side to the flow rate transmitter 2A of the safety standard mass flow meter 2 in the hazardous area is limited to the ignition limit or less by the barrier circuit.

(2) The signal converter B is electrically insulated (isolated) as a further safety measure before supplying the signal from the safe power supply current repeater A to the digital indicating controller C which is a non-safety device. And a standard signal is output to the next digital indicating controller C.

(3) The digital indicating controller C receives the standard output signal (4... 20 mA) from the signal converter B as a measured value (PV value), displays it on the indicator of the display unit 11, and sets the target setting signal (SP Value: for example, 50 liters per minute), and if there is a deviation, a control output signal for eliminating the deviation is supplied to the operation end by a feedback control (PID control) function, and a target setting signal (SP Value) and measurement signal (PV value) are controlled to match. With this control output signal, it is possible to drive the air pressure adjustment valve 3 which is a pressure-proof explosion-proof operation end.

  For example, when the operation end is the air pressure control valve 3, the gas flow rate is increased or decreased by adjusting the on-off valve by the control output signal, and the target setting signal (SP value) and the measurement signal (PV value) coincide. Control to do.

  The digital indicating controller C has a flow rate upper / lower limit alarm output function (not shown).

(4) The power supply circuit D supplies power to each component device (A, B, C) in the casing 1 via the no-fuse breaker V. Further, a fuse is disposed on the primary power supply side of the main power supply current repeater A for protection. However, the primary source power supply must be 250 Vac or 250 Vdc or less.

  In the following, the operation description when the process control module in the present embodiment is applied to a mass flow control system for gas flow rate control will be described in detail with reference to FIG.

  First, a 24 Vdc main power supply is supplied from the main power supply current repeater A to the main mass flow meter 2.

  The main power supply current repeater A receives an output signal (measurement value: 15... 20 mA) from the main safety mass flow meter.

  So-called signal processing that produces the same signal as the output signal (measured value: 15 ... 20 mA) from the main safety mass flow meter after electrically isolating the main safety / non-main safety with the main power supply current repeater A The signal (15... 20 mA) is output to the signal converter B.

  The signal converter B receives this signal (15... 20 mA) as an input, further electrically isolates it, converts the signal into a standard signal (4... 20 mA), and outputs it to the next digital indicating controller C. .

  The digital indicating controller C receives the output signal (4... 20 mA) from the signal converter B as a measured value (PV value), displays the measured value on the display unit 11, and simultaneously displays the SP (target) of the display unit 11. Set the target flow rate in (Setting).

  Then, the controller built-in controller (not shown) automatically compares the measurement signal (PV value) and the target setting signal (SP value).

  The opening of the air pressure control valve 3 always fluctuates due to changes in process conditions (pressure, temperature fluctuation, etc.) and the influence of electrical noise on the electrical signal (this is called disturbance), and therefore the measurement signal (PV value) And a target setting signal (SP value).

  If there is a deviation, the operation end (in this case, an electric signal is converted into air pressure so that the deviation is zero, and the needle on-off valve 4 is opened and closed through a diaphragm that expands or contracts by the air pressure, for example. Thus, the control signal is output to the air pressure control valve 3) that adjusts the flow rate, and the flow rate is increased or decreased by adjusting the opening of the air pressure control valve 3. As a result, the measured value is synchronized with the target value. Adjustments are made.

  The digital indicating controller C has a remote local changeover switch function. When switched to remote, the SP (target value setting) is switched from the local setting from the digital indicating controller C to the external setting by remote and receives the external setting signal. The flow rate is adjusted with respect to the external setting signal.

  Further, from the digital indicating controller C, the measurement value signal is a higher-level device, for example, a distributed control system (DCS: distributed-control-system has a control device connected to each device constituting the system via a network. Data logger, PLC (programmable-logic-controller is a product name of Mitsubishi Electric, which is a control device developed as an alternative device for a relay circuit), and the monitoring center server S side of a PC, etc. Is output.

  On the monitoring center server S side, this external output signal is monitored, and an external setting signal corresponding to this is generated, and the setting signal is directly supplied to the digital indicating controller C built-in controller (local setting at the time of remote control) Is bypassed).

  The present invention is a process control module specializing mainly in overseas products with various TIIS international technical guidelines and technical standards certified intrinsically safe transmitters such as flow meters, pressure gauges, etc. TIIS explosion-proof guideline certified intrinsically safe explosion-proof transmitters and other products that are mainly compatible with domestic equipment can be added.

  Although the application is not different from the current industrial field, the use area of the intrinsically safe explosion-proof measurement control system can be expanded, and it is widely used as a technique for explosion-proof purposes.

A ... Genuine power supply current repeater B ... Signal converter C ... Digital indicating controller D ... Power supply circuit S ... Monitoring center server V ... No-fuse breaker E ... AC adapter 1 ... Casing (module)
2 ... Technical standard certified genuine mass flow meter 2A ... Flow rate transmitter 3 ... Pneumatic control valve 5 ... Pneumatically operated diaphragm actuator 6 ... TIIS certified explosion-proof electropneumatic positioner 7 ... Connection terminal 8 ... Bulk for pulling in secure cable DESCRIPTION OF SYMBOLS 11 ... Display part 12 ... PV display part 13 ... Data display part 14 ... Bar graph display part 15 ... Group display part 16 ... Symbol display part 17 ... Event display part 18 ... Key navigation display part 19 ... Parameter display level part 20 ... Status Display unit 21 ... Security display unit 22 ... Ladder operation display unit 23 ... Second loop display unit 24 ... Manual set enter key

Claims (6)

In order to prevent explosion in the process measurement and control system for flammable fluids installed in hazardous areas, it has a process control module installed in non-hazardous areas.
The process control module
TIIS technical standard certification intrinsically safe explosion-proof power supply current repeater that limits the electrical energy supplied to various transmitters based on TIIS international technical guidelines / technical standard certification of process measurement and control systems,
A signal converter that converts the signal received by the intrinsically safe explosion-proof power supply current repeater from the transmitter and outputs a standard signal;
A digital indicating controller that receives a standard output signal from the signal converter as a measurement value and controls the target setting signal and the measurement value to match,
Power supply circuit for supplying power to each of the intrinsically safe explosion-proof power supply current repeater, signal converter, and digital indicating controller;
A process control module that integrates and integrates individual functions of the system into a casing.   Intrinsically safe power supply current repeater supplies intrinsically safe power to various transmitters based on TIIS international technical guidelines / technical standards certification for process measurement and control systems, receives current signals from transmitters, and uses barrier circuits. The process control module according to claim 1, wherein the electric energy supplied from the non-hazardous area side to the transmitter in the hazardous area is limited to an ignition limit or less.   2. The signal converter as claimed in claim 1, wherein the signal converter electrically isolates and outputs a standard signal as a further safety measure before supplying the signal from the intrinsically safe explosion-proof power supply current repeater to the circuit of the non-intrinsic safety device. Process control module.   The power supply circuit supplies power to each component in the module via a no-fuse breaker, and a fuse is disposed on the primary power source side of the intrinsically safe power supply current repeater for protection. Process control module.   The digital indicating controller has a remote local changeover switch function. At the remote switching position, the target value setting is switched from the setting from the digital indicating controller to the external setting, and the external setting signal is received. The process control module according to claim 1, wherein an operation end in the process measurement / control system is adjusted.   The process control module according to claim 1, wherein a measurement value signal is output from a digital indicating controller to a host device including a DCS, a data logger, a PLC, and a PC.

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