JP3204058B2 - Field bath positioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field bus positioner which receives a digital signal together with a power supply from a field bus connected to a host system, and controls a valve opening degree of the valve in response to the digital signal. The present invention relates to a field bus positioner improved so that failure data of a valve or surrounding environmental data can be easily grasped.

[0002]

2. Description of the Related Art FIG. 6 is a configuration diagram showing a configuration of a conventional field bus positioner (hereinafter, simply referred to as a positioner). One end of the positioner 10 is connected to a host system (not shown) such as a digital control system via a field bus 11.

In the field bus 11, a digital signal is superimposed on a DC power supply. The DC power supply supplies power to a field device such as the positioner 10, and the digital signal causes a communication between the host system and the field bus positioner. , So that digital communication is possible.

[0004] controlling the valve opening degree to supply the output pressure P ₀ to correspond to the digital signal by using the boost pressure P _S with boost pressure P _S is supplied to the positioner 10 to the valve 14 . The boost pressure P _S is the boost pressure meter 1
2 and the output pressure P ₀ is monitored by the output pressure meter 13.

Further, the field bus 11 is provided with a temperature sensor 15 which is energized by a DC power supply of the field bus and detects an ambient temperature, or a pressure sensor 16 which measures a line pressure to which the valve 14 is connected. Etc. are connected.

[0006]

However, the above-described positioner 10 has the following disadvantages. Positioner 10 when you want to check the boost pressure P _S or the output pressure P _S must read visually these pressure from boost pressure meter 12 or the output pressure meter 13.

Therefore, when any trouble occurs in the valve 14, it is necessary to go to the site and check the indication of the supply pressure meter 12 or the output pressure meter 13, so that there is a problem that it is difficult to respond urgently.

In order to monitor the ambient temperature and the line pressure via the field bus 11, the temperature sensor 15 or the pressure sensor 1 corresponding to the field bus 11 must be individually provided.
6 must be connected and data must be collected on the spot from its own reading, so that the cost is high and the range of data that can be collected is limited.

[0009]

According to the present invention, as a main structure for solving the above-mentioned problems, a digital signal is supplied from a field bus connected to a host system together with a power supply together with a power supply. In a positioner for controlling a valve opening of a valve, an auxiliary input terminal capable of inputting sensor signals from various sensors is provided in the positioner,
The sensor signal obtained from the auxiliary input terminal is transmitted to the host system via the field bus.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention.

Reference numeral 11 denotes the same field bus as the field bus shown in FIG. The valve 14 is the same as the valve 14 shown in FIG. A positioner 20 is connected between the field bus 11 and the valve 14.

The positioner 20 includes a transmission / reception circuit 21,
Modem 22, read-only memory 23, random access memory (RAM) 24, microprocessor (CP
U) 25, bus 26, digital / analog converter (D /
A) 27, valve drive unit 28, supply pressure sensor 29, output pressure sensor 30, analog / digital converter (A / D) 3
1, a displacement sensor 32, a multiplexer 33, an auxiliary input terminal 34, and the like.

The transmission / reception circuit 21 is connected to the field bus 11 via terminals T _A and T _B.
1 to generate a circuit voltage + V _CC to be used in the positioner 20 in response to the supply of the DC current, and also sends the circuit voltage + V _CC to the auxiliary input terminal 34.

Further, the transmission / reception circuit 21 transmits a communication digital signal from an upper system such as a digital control system (not shown) from the field bus 11 or a small-sized handheld terminal for digital communication connected to the field bus 11. It functions as an interface for receiving and, conversely, sending out digital signals from the positioner 20 to the field bus 11.

The modem 22 includes a transmission / reception circuit 21 and a bus 26
And converts the digital signal for communication with the host system into serial data or parallel data and performs modulation and demodulation so as to be suitable for transmission and reception.

The read-only memory 23 stores, for example, operation programs for various operations executed in the positioner 20, or predetermined parameters, and the like. These operation programs and the like also control the microprocessor 25. Then, it is taken out as necessary and the operation is executed.

The operation program includes, for example, a proportional operation, an integral operation, a differential operation, a scaling operation, and a non-linear correction operation for input data. Parameters necessary for these operations are also stored as necessary. I have.

The random access memory 24 includes a supply pressure sensor 29, an output pressure sensor 30, or the auxiliary input terminal 3.
4 is temporarily stored under the control of the microprocessor 25, and is rewritten as necessary.

The valve driving unit 28 is provided with a supply pressure P _S from outside.
Is supplied via a pressure sensor 29, and the air pressure corresponding to the valve opening signal output from the digital / analog converter 27 is supplied to the valve 14 via the output pressure sensor 30 to displace the stem of the valve.

The displacement sensor 32 converts the displacement of the stem into an electric signal and outputs it to the analog / digital converter 31. The analog / digital converter 31 converts a signal corresponding to the displacement into a digital signal and outputs the digital signal to the microprocessor 25.

The multiplexer 33 has an auxiliary input terminal 34
, Input pressure data output from the air pressure sensor 29, and output pressure data output from the output pressure sensor 30.

These data are stored in the microprocessor 2
The switching is performed at a predetermined timing by a switching signal output from 5, and stored in a predetermined area of the random access memory 24 under the control of the microprocessor 25 via the analog / digital converter 31.

The auxiliary input terminal 34 is connected to a terminal T ₁ ,
It is composed of T ₂ , T ₃ , T ₄ , T ₅ , T _6, T _S , T _0, etc. Among them, the terminal T ₁ receives the circuit voltage + V _CC generated by the transmission / reception circuit 21. And is supplied to a circuit power supply of an external sensor connected to the auxiliary input terminal 34.

Signals from an external sensor are input to the terminals T _{2 to} T ₄ , and the terminal T ₆ is used as a common potential point COM. The signals of the supply pressure sensor 29 and the output pressure sensor 30 are applied to the terminals T _S and T ₀ , respectively.

Next, the operation of the positioner 20 configured as described above will be described. Is from the host system is digital data D _V is transmitted corresponding to the valve opening degree of the valve 14 via the field bus 11 and the modem 22 bus 26
Is stored in a predetermined area of the random access memory 24 via the.

The microprocessor 25 executes necessary operations using the stored data _DV and transmits the necessary operations to the valve drive unit 28 via the digital / analog converter 27.
Valve drive unit 28 converts the output pressure signal P ₀ is a air pressure corresponding to the data D _V for driving the valve 14.

[0027] The actuation of the valves 14, since the stem S _m of the valve 14 is displaced, and outputs to the analog / digital converter 31 as a displacement signal D _S analog this by detecting the displacement sensor 32.

The analog / digital converter 31 'converts the microprocessor 25 the displacement data D _S' the displacement signal D _S digital displacement data D _S stores in a predetermined area of the random access memory 24.

The microprocessor 25, the calculation procedure previously stored in the read only memory 23 as a random access memory 24 displacement data D _S of the data D _V Toko corresponding to the valve opening degree stored in the 'match Therefore control.

Thus, the microprocessor 25
While obtaining the valve opening degree corresponding to the data D _V is a set value for controlling the valve opening degree is transmitted from the host system by, the operation control is a fundamental function required to positioner 20.

In addition, the microprocessor 25 includes:
In response to a request from the host system, the supply pressure data output from the supply pressure sensor 29 and the output pressure data output from the output pressure sensor 30 are obtained via the multiplexer 33, and the modem 22, the transmission / reception circuit 21, the field The data is transmitted to the host system via the bus 11, where the presence or absence of an abnormality is monitored.

Further, the microprocessor 25 acquires various environmental data obtained at the auxiliary input terminal 34 via the multiplexer 33 in response to a request from the host system, and obtains the modem 22, the transmission / reception circuit 21, and the field bus 11
Is transmitted to the higher-level system via the PC and monitored here.

The setting of the valve opening, the request for environmental data or the monitoring of the result are performed not only from the host system but also from a small hand-held communication terminal arbitrarily connected to the field bus 11, for example. Can maintain the same function.

FIG. 2 is a circuit diagram showing a circuit configuration between the transmission / reception circuit 21 and the modem 22 in FIG. The field bus 11 is connected to terminals T _A and T _B, and a transistor Q ₁ , a transistor Q ₂ , a resistor R ₁ , and a feedback resistor R _f are connected in series to both ends thereof.

The connection point of one end of the resistor R ₁ and a feedback resistor R _f, is a common potential point COM of the circuit, the common potential point C
And OM, between the emitter collector terminals T _A connected to the transistor Q _1, Zener diode Z to the capacitor C ₁ is connected in parallel is connected.

[0036] collector to the base of the transistor Q _1,
A transistor Q ₂ whose emitter is connected to the other end of the resistor R ₁
The base is connected to the output terminal of the operational amplifier Q _3. The algebraic sum of the operational amplifier non-inverting input terminal of Q ₃ (+) is the feedback voltage V _f generated by the current I ₀ flowing through the reference voltage E _S of the reference voltage source 35 to the feedback resistor R _f, the resistance R _2,
R ₃ , a divided voltage V _D divided by the feedback resistor R _f is applied.

Further, the inverting input of the operational amplifier Q ₃ (-)
A communication voltage V _CM obtained by dividing a communication voltage obtained from a communication signal output from the modem 22 through the waveform shaping circuit 36 by the resistors R ₄ and R ₅ is applied.

Further, the digital signal transmitted from the field bus 11 via the terminal T _A , such as the valve opening, is cut off the DC component by the capacitor C ₂ and then received by the receiving filter 3.
The filter is filtered at 7, and unnecessary noise is removed at the comparator 38 and transmitted to the modem 22.

Next, the operation of the transmitting / receiving circuit 21 configured as described above will be described. The operational amplifier Q ₂ is, as the reference voltage E _S divided by the divided voltage V _D and the feedback voltage V _f satisfies matches, by controlling the base current of the transistor Q ₁ through a base of the transistor Q ₂ feedback The current I ₀ flowing through the resistor R _f is controlled.

As a result, a constant Zener voltage is generated at both ends of the Zener diode Z, and this voltage + V _CC is used as a circuit voltage for operating the circuit. The digital signal transmitted from the field bus 11 is a capacitor C
₂ , transmitted to the modem 22 via the reception filter 37 and the comparator 38.

Further, communication signal transmitted from the positioner 20, the field bus 11 as a form superimposed on the current I ₀ by controlling the internal resistance of the transistor Q ₁ through a base of the transistor Q ₂ as the communication voltage V _CM transmission Is done.

FIG. 3 is a configuration diagram showing a configuration when a three-wire sensor is connected as an external sensor. 3-wire sensor 3
9 detects, for example, the ambient temperature near the position where the positioner 20 is installed.

The power supply terminal of the three-wire sensor 39 is connected between terminals T ₁ and T ₆ which are one of the auxiliary input terminals 34 of the positioner 20, and is supplied with a circuit voltage + V _CC required for signal processing. You.

For example, the temperature signal V _T1 detected by the three-wire sensor 39 is supplied to the terminal T _{5 of the} auxiliary input terminal 34.
Is output to one of the input terminals of the multiplexer 33 in the positioner 20 via the.

Thereafter, the temperature signal V _T1 is supplied to the multiplexer 3
3 and after that the microprocessor 25
As a result, the data is stored in a predetermined area of the random access memory 24 and subjected to necessary signal processing.

FIG. 4 is a configuration diagram showing a configuration when a two-wire sensor is connected as an external sensor. Two-wire sensor 4
“0” shares the power supply line and the output signal line and detects, for example, the ambient temperature near the positioner 41 is installed.

The power supply terminal of the two-wire sensor 40 is connected between terminals T ₁ and T ₆ , one of the auxiliary input terminals 34 of the positioner 41, and is supplied with a circuit voltage + V _CC required for signal processing. that is, the temperature signal in this case is transmitted to the terminal T ₆ as a current signal I _S.

Inside the positioner 41, a resistor R ₆ for current / voltage conversion is connected, and this current signal I _S is converted by the resistor R ₆ into a temperature signal V _T2 which is a voltage signal for the common potential point COM. After that, the data is output through the multiplexer 33, and thereafter, stored in a predetermined area of the random access memory 24 by the microprocessor 25 and subjected to necessary signal processing.

FIG. 5 is a configuration diagram showing the configuration of an external sensor for obtaining power from the field bus. In this case, an example is given in which the external sensor 42 detects the ambient temperature near the position where the positioner 43 is installed.

The external sensor 42 is supplied with power from the field bus 11 in the vicinity of the positioner 43, the temperature signal to the terminal T ₂ and T _6, which is one of the auxiliary input terminal 34 of the positioner 43 from the detection of the environmental temperature V Outputs _T3 .

In this case, since the external power supply sensor 42 needs to be insulated DC from the circuit power supply + V _CC of the positioner 43 in order to obtain power from the field bus 11, the temperature signal V is supplied to the multiplexer 33 via the isolator 44.
Outputs _T3 .

In the configuration shown in FIG.
4 is housed inside the positioner 43, but the present invention is not limited to this, and the isolator 44 may be housed inside the external power sensor 42 and transmitted to the positioner as an insulated signal.

In the above description, the case where the environmental temperature is measured as an external sensor has been described. However, the present invention is not limited to this, and the piping (line) to which the valve 14 is connected is described.
An arbitrary sensor such as measurement of the fluid temperature of the fluid flowing through or the line pressure can be connected.

[0054]

As described above, concretely together with the embodiments of the present invention.
According to the first aspect of the present invention, as described,
Sensor signals from various sensors
Auxiliary input terminal for inputting signals
Sensor signal from the host system via the field bus.
System, so in the event of an emergency, the supply pressure P
_SOr output pressure P_SInstantly and easily
Ambient temperature using an external sensor.
Monitor temperature, fluid temperature, line pressure, etc. at low cost
Therefore, it is easy to collect various data
it can.

According to the second aspect of the present invention, since the circuit power is obtained from the auxiliary input terminal, there is an advantage that the external sensor can be easily driven using the circuit power.

According to the third and fourth aspects of the present invention, in addition to the effect of the second aspect of the present invention, even if a three-wire sensor is used as an external sensor connected to the auxiliary input terminal, a two-wire sensor can be used. A type sensor may be used, and various sensor configurations are possible.

According to the fourth aspect of the present invention, the driving power of the external sensor is supplied from the field bus and the sensor signal is input to the auxiliary input terminal.
Even an external sensor that consumes large power can be easily connected to the auxiliary input terminal.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing a circuit configuration between a transmission / reception circuit and a modem in FIG. 1;

FIG. 3 is a configuration diagram showing a configuration when a three-wire sensor is connected as an external sensor.

FIG. 4 is a configuration diagram showing a configuration when a two-wire sensor is connected as an external sensor.

FIG. 5 is a configuration diagram showing a configuration of an external sensor that obtains power from a field bus.

FIG. 6 is a configuration diagram showing a configuration of a conventional field bus positioner.

[Explanation of symbols]

 10, 20, 41, 43 Positioner 11 Field bus 12 Supply pressure meter 13 Output pressure meter 14 Valve 15 Temperature sensor 16 Pressure sensor 21 Transmission / reception circuit 22 Modem 25 Microprocessor 29 Supply pressure sensor 30 Output pressure sensor 33 Multiplexer 34 Auxiliary input terminal 39 3-wire sensor 40 2-wire sensor 42 External power supply sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-141202 (JP, A) JP-A-2-76201 (JP, U) JP-A-2-93502 (JP, U) JP-A-3-93 62201 (JP, U) Jiko 3-20561 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F15B 9/07 F15B 5/00

Claims (5)

(57) [Claims] 1. A field bus positioner which receives a digital signal together with power from a field bus connected to a host system and controls a valve opening degree of a valve in response to the digital signal. In the field bus positioner, various sensors are connected to the field bus positioner. A field bus positioner, comprising: an auxiliary input terminal capable of inputting the sensor signal of (1), and transmitting the sensor signal obtained from the auxiliary input terminal to the host system via the field bus. 2. The field bus positioner according to claim 1, wherein a circuit power supply used in said field bus positioner is applied to said auxiliary input terminal, and an external sensor is driven using said circuit power supply. 3. The field bus positioner according to claim 2, wherein the sensor signal is transmitted to the auxiliary input terminal as a voltage signal. 4. The field bus positioner according to claim 2, wherein the sensor signal is transmitted as a current signal to the auxiliary input terminal. 5. A driving power supply for the external sensor is supplied from the field bus, and the sensor signal is transmitted from the field bus in a direction insulated from the field bus either before or after input of the auxiliary input terminal. The field bus positioner according to claim 1, wherein