Disclosure of Invention
The present application is directed to provide an IO channel circuit, so as to solve the problem that a DI module and a DO module in an input/output module cannot be multiplexed.
To solve the above technical problem, an IO channel circuit includes: the amplitude limiting circuit comprises a first switching tube and a second switching tube;
the first end of the first switch tube is used for being connected with a first power supply, the second end of the first switch tube is connected with the anode of an input/output interface, the control end of the first switch tube is connected with a control circuit, the first end of the second switch tube is connected with the first end of the amplitude limiting circuit, the second end of the second switch tube is connected with the anode of the input/output interface, the control end of the second switch tube is connected with the control circuit, the anode of the input/output interface is connected with the control circuit, and the cathode of the input/output interface is connected with the second end of the amplitude limiting circuit and is grounded;
when the circuit is used as an input channel circuit, the control circuit controls the first switch tube to be opened and the second switch tube to be closed, and when the circuit is used as an output channel circuit, the control circuit controls the second switch tube to be opened and the first switch tube to be opened and closed according to the received signals.
Preferably, the circuit further comprises: a current limiting circuit;
the first end of the current limiting circuit is used for being connected with the first power supply, and the second end of the current limiting circuit is connected with the first end of the first switching tube.
Preferably, the circuit further comprises: a rectifier diode;
the negative pole of the rectifier diode is used for being connected with the first power supply, and the positive pole of the other end of the rectifier diode is connected with the control end of the first switch tube.
Preferably, the first switch tube and the second switch tube are MOS tubes.
Preferably, the circuit further comprises: and one end of the filter circuit is connected with the anode of the input/output interface, and the other end of the filter circuit is grounded.
Preferably, the limiter circuit is a diode limiter.
Preferably, the control circuit comprises an analog-to-digital converter, a reference source and a drive circuit.
Preferably, the reference source is a 2.5V reference source.
Preferably, the filter circuit is a filter capacitor.
In order to solve the above problem, the present application further provides a DCS system including the IO channel circuit.
The IO channel circuit provided by the application can realize the conversion between the DI module and the DO module by controlling the opening and closing of the first switch tube and the second switch tube, when the input and output interface is connected with a field power supply, the DI module is used, at the moment, the second switch tube is closed, the first switch tube is disconnected, the voltage of the input and output interface is obtained, the voltage is controlled in the range which can be identified by the control circuit after being limited by the limiting circuit, so that a corresponding digital signal is obtained, when the input and output interface is connected with a load, the DO module is used, the second switch tube is disconnected, the opening and closing of the first switch tube are controlled by the value of the digital signal received by the control circuit, so that the corresponding control of the load on the field is realized, the functions of the DI module and the DO module are simultaneously realized on the same circuit, compared with the DI module and the DO module which are not used by different circuits respectively, corresponding circuit disassembly is not needed when input and output are required to be switched, flexibility and maintainability of system IO channel circuit configuration are improved, and system construction cost and later maintenance cost are reduced.
The DCS that this application provided includes above-mentioned IO passageway circuit, and beneficial effect is the same as above.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the present application.
The core of this application is to provide an IO passageway circuit, fig. 1 is a DCS system structure schematic diagram, the IO passageway of present DCS system is with the form access system of IO module, an IO equipment module generally comprises 8 passageways or 16 passageways IO passageways of the same type, like DI module (digital input module), DO module (digital output module), AO module (analog output module), AI module (analog acquisition module), the IO passageway that the system held is also more and more simultaneously along with DCS system scale is bigger and bigger, the IO equipment module quantity that needs is also more and more, and different kinds of IO module can not substitute each other, be not convenient for the group building or the later stage DCS maintenance management of DCS system. The DI channel and the DO channel of the existing DCS input type IO module realization scheme can not be multiplexed, the DI module and the DO function can not be realized on the same IO module at the same time, the IO module has various types, and the system cost and the maintenance cost are increased, for example, the field A and the field B are mutually communicated, when an input signal is made on the field A to control the field B, the field A is connected with the DI channel, the field B is connected with the DO channel, when the field B is required to input, the DO channel on the field B needs to be firstly removed and then the DI channel is installed, which is very troublesome, in view of the above situation, the DI and DO general digital quantity realization method provided herein can multiplex the DI channel and the DO channel in the same IO module, thereby increasing the flexibility of the DCS IO module, facilitating the early-stage construction and later-stage maintenance management of the DCS system, and only needing to connect the corresponding load or power supply on the input and output interface, the DO channel is used when the load is connected, the DI channel is used when the power supply is connected, and when IO conversion is required on site, the circuit does not need to be disassembled and assembled.
In order that those skilled in the art will better understand the disclosure, the following detailed description will be given with reference to the accompanying drawings.
Fig. 2 is a schematic diagram of an IO channel circuit provided in an embodiment of the present application, and as shown in fig. 2, the IO channel circuit includes: the limiter circuit 1, the first switch tube S1, the second switch tube S2;
a first end of the first switch tube S1 is configured to be connected to a first power VCC, a second end of the first switch tube S1 is connected to an anode of the input/output interface, a control end of the first switch tube S1 is connected to the control circuit, a first end of the second switch tube S2 is connected to a first end of the amplitude limiting circuit 1, a second end of the second switch tube S2 is connected to an anode of the input/output interface, a control end of the second switch tube S2 is connected to the control circuit, an anode of the input/output interface is connected to the control circuit, and a cathode of the input/output interface is connected to a second end of the amplitude limiting circuit 1 and grounded;
when the input channel circuit is used, the control circuit controls the first switch tube S1 to be opened and the second switch tube S2 to be closed, and when the output channel circuit is used, the control circuit controls the second switch tube S2 to be opened and controls the first switch tube S1 to be opened and closed according to the received signals.
In practical application, the input channel circuit or the output channel circuit is determined by judging whether the input/output interface is connected to a field power supply or a load, if the input channel circuit is connected to the field power supply, the input channel circuit is the control circuit, the control circuit collects input voltage (usually 0-24V) of the field power supply, the voltage is limited in a range which can be identified by the control circuit through a limiting circuit, and the collected input voltage is converted into a digital signal, for example, the identification range of the control circuit is 0-2.5V, when the voltage of 0V is received, the collected digital signal is 0, when the voltage of 24V is received, the voltage is limited to 2.5V, the collected digital signal is 1, and it can be understood that the digital signal 0 is low level and the 1 is high level. If the input/output interface is connected with a load, the input/output interface is an output channel circuit, for example, if the load is a relay, the output signal of the control circuit is determined to be 0 or 1, if the output signal is 0, the first switch tube S1 is controlled to be opened, the relay and the first power source VCC are opened, that is, the relay is controlled to be opened, and if the output signal is 1, the first switch tube S1 is controlled to be closed, and the relay and the first power source VCC are turned on, that is, the relay is controlled to be closed.
Those skilled in the art will appreciate that the configuration shown in fig. 2 does not constitute a definition of an IO channel circuit and may include more or fewer components than those shown. It should be noted that, the first switch tube S1 and the second switch tube S2 provided in the present application have three ports, an input end, an output end, and a control end, so that the first switch tube S1 and the second switch tube S2 are triodes or field effect transistors, and are not limited to the embodiment because the first switch tube and the second switch tube shown in fig. 2 are MOS transistors, that is, the types and types of the first switch tube and the second switch tube in the embodiment are not specifically limited. The type of the amplitude limiting circuit 1 is not limited, the control circuit contains content, namely the control circuit can be used as an acquisition circuit to acquire corresponding voltage and convert the voltage into a digital signal, and the switching on and off of the switching tube can be controlled according to the digital signal, and the specific type of the control circuit is not limited.
The IO channel circuit provided by the application can realize the conversion between the DI and DO modules by controlling the opening and closing of the first switch tube S1 and the second switch tube S2, when the input/output interface is connected with a field power supply, the DI module is the DI module, the second switch tube S2 is closed at the moment, the first switch tube S1 is disconnected, the voltage of the input/output interface is obtained, after the voltage is limited by the limiting circuit 1, the range which can be identified by the control circuit is controlled, so that a corresponding digital signal is obtained, when the input/output interface is connected with a load, the DO module is the DO module, the second switch tube S2 is disconnected, the opening and closing of the first switch tube S1 are controlled by the value of the digital signal received by the control circuit, so that the corresponding control on the load on the field is realized, the functions of the DI module and the DO module are simultaneously realized on the same circuit, and different circuits are respectively used compared with the DI module and the DO module before, corresponding circuit disassembly is not needed when input and output are required to be switched, flexibility and maintainability of system IO channel circuit configuration are improved, and system construction cost and later maintenance cost are reduced.
In practical application, considering the complex situation of the site in the DCS system, a short circuit may occur externally, or a load may overflow, and therefore, considering the problem of site security, the preferred scheme is provided in this embodiment, and the IO channel circuit further includes: a current limiting circuit 2;
the first terminal of the current limiting circuit 2 is connected to the first power VCC, and the second terminal of the current limiting circuit 2 is connected to the first terminal of the first switch tube S1.
It should be noted that the current limiting circuit 2, i.e. the circuit for limiting the current, may be one of current limiting resistors, current limiting valves, current limiters, etc., or a circuit formed by combining these components, and the specific type of the current limiting circuit 2 is not limited in this embodiment.
When the first switch tube S1 is closed, the first power source VCC is connected to a load, and the current limiting circuit 2 is provided to protect the power source in consideration of the possibility of a short circuit of the input/output interface, and also to protect the control circuit and the connected load elements from being damaged by overcurrent due to various field complications.
In order to reduce the influence of the ac power on the IO channel circuit, the present embodiment provides a preferable scheme, and the IO channel circuit further includes: a rectifier diode;
the cathode of the rectifier diode is used for being connected with a first power supply VCC, and the anode of the rectifier diode is connected with the control end of the first switch tube S1.
A rectifier diode is a semiconductor device for converting alternating current to direct current. The most important characteristic of a diode is one-way conductivity. In the circuit, current can only flow in from the anode and flow out from the cathode of the diode. The rectifier diode has a significant unidirectional conductivity. The rectifier diode can be made of semiconductor germanium or silicon. The silicon rectifier diode has high breakdown voltage, small reverse leakage current and good high-temperature performance. High-voltage high-power rectifier diodes are usually made of high-purity monocrystalline silicon (reverse breakdown is easy when the doping is more).
The rectifier diode in this embodiment is used for cutting off first power VCC and control circuit, prevents that the voltage of first power VCC from influencing control circuit, and under alternating current power supply's effect, rectifier diode periodically switches on and cuts off, makes the load obtain the pulsation direct current for load work is more stable.
In the above embodiments, the types of the first switch tube S1 and the second switch tube S2 are not limited, and it is preferable that the first switch tube S1 and the second switch tube S2 are MOS transistors.
The MOS transistor is a metal-oxide-semiconductor (semiconductor) field effect transistor or is referred to as a metal-insulator-semiconductor (insulator). The source and the drain of the MOS tube can be reversed, and the source and the drain are both N-type regions formed in a P-type channel. In most cases, the two poles are identical, and even if the two poles are reversed, the performance of the device is not affected. Such devices are considered symmetrical. That is, the first end and the second end of the first switch tube S1 and the second switch tube S2 mentioned in the above embodiments may be the source or the drain of the MOS transistor in this embodiment, and the control end is the gate, and the specific type of the MOS transistor is not specifically limited herein.
In practical applications, because the MOS transistor is smaller and more power-saving than most field effect transistors due to the semiconductor material and nature, the MOS transistor is easy to install and also saves energy.
In view of the potential voltage floating problem due to field instability, the present embodiment proposes a preferable solution, and the circuit further includes: and one end of the filter circuit is connected with the anode of the input/output interface, and the other end of the filter circuit is grounded.
It should be noted that the type of the filter circuit is not limited herein, and may be a filter capacitor, a resistor, an inductor, or a combination thereof. Filtering the IO channel circuit can make the input of the whole IO channel circuit more stable.
In the above embodiment, the limiter circuit 1 is not limited, but in the present embodiment, a preferable scheme is proposed, and the limiter circuit 1 is a diode limiter.
The diode used for clipping is referred to as a diode limiter. Clipping is to limit the amplitude of the signal to a desired range. Since most of the circuits required for clipping are high-frequency pulse circuits, high-frequency carrier circuits, medium-high frequency signal amplification circuits, high-frequency modulation circuits, etc., diode clips are required to have steep U-I characteristics, so that the diode clips have good switching performance.
The diode amplitude limiter is high in conduction speed and stable in voltage drop, and therefore the working efficiency and stability of an IO channel circuit can be improved.
In the above embodiments, the control circuit is not limited, and the preferred solution of the present embodiment is that the control circuit includes an analog-to-digital converter, a reference source, and a driving circuit.
The analog-to-digital converter is used to convert an analog signal (electrical signal) and a digital signal, that is, convert the acquired voltage into a digital signal, the driving circuit is used to control the on/off of the switching tube, and the reference source is used to determine the value of the acquired voltage-converted digital signal.
In the above embodiments, the reference source is not limited, and a preferred scheme is proposed here, and the reference source is a 2.5V reference source.
It should be noted that, due to the requirement of the control circuit, most of the field voltage is limited between 0 and 2.5V by the limiter circuit 1, so that the accuracy of the circuit can be improved by selecting 2.5V as the reference source.
In the above embodiments, the form of the filter circuit is not limited, and a preferable scheme is proposed here, and the filter circuit is a filter capacitor C1.
The filter capacitor C1 is selected as a filter because the filter capacitor C1 has high reliability, stable performance and single-phase filtering.
Fig. 3 is a schematic structural diagram of a DCS system provided in an embodiment of the present application, where the DCS system includes an IO channel circuit mentioned in the foregoing embodiment, and as shown in fig. 3, DI and DO channels in the DCS system are multiplexed, and compared with a DCS system in which a DI module and a DO module are independently used, there is no need to disassemble a corresponding circuit when input and output need to be switched, so that flexibility and maintainability of a DCS system configuration are increased, and a building cost and a post-maintenance cost of the DCS system are reduced.
The IO channel circuit provided in the present application is described in detail above. The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.