KR20030018612A - The circuit controling interface central control unit and input or output module in the programmable logic controller - Google Patents

Abstract

PURPOSE: An input/output module control circuit of a PLC(Programmable Logic Controller) control part is provided, which overcomes the limit of driving capability according to fan layout increase. CONSTITUTION: A number of input/output modules(30) connected to thousands of points of input/output devices of a factory facility are connected to a central control part(10) through an address/data bus. And the central processing part comprises a central processing unit(11) and a decoder(13) and an A/D(Analog/Digital) bus driver(12). The A/D bus driver drives an address/data bus(20) to transmit data to the input/output module or the central processing part. And the decoder decodes a module selection input signal(IB) being output from the central processing unit and then outputs a module selection signal(/MID).

Description

Input and output module control circuit of PSI controller {THE CIRCUIT CONTROLING INTERFACE CENTRAL CONTROL UNIT AND INPUT OR OUTPUT MODULE IN THE PROGRAMMABLE LOGIC CONTROLLER}

The present invention relates to the input and output module control circuit of the PSI control unit, more specifically, when the interface between the PIC central control unit and the input and output module, in accordance with the increase in the fan out by a plurality of input and output modules An input / output module control circuit of a PI controller which prevents the driving force of the controller and the address / data drive drive from being restricted.

Programmable Logic Controller (PLC), which is commonly used for the automation of plant equipment in the industrial field, is a central control unit including a central processing unit and an input module that receives a signal from a sensor or a switch. And an output module for transmitting a control signal to a motor or valve, which is a controlled object, a high speed counter, a communication module, a PID control module, a positioning module, and the like.

In addition, PI can play an important role in the construction of unmanned automation system in the future as it is possible to automate large-scale factories through communication such as robots, upper computers, and Ethernet.

In the above-mentioned PSI facility used for factory automation, the process of transmitting, receiving and processing necessary data between PLC and digital or analog I / O modules connected to input and output devices installed in various places of the factory for centralized control is required. It is especially important to be efficient.

FIG. 1 is a conceptual diagram illustrating a process in which a general PI control unit accesses an input / output module. As shown, the central control unit 1 selects input and output ports provided in the plurality of input and output modules 4 through the address / data bus 2 to transmit or read data necessary for control to the corresponding port. It will control the connected equipment. Briefly describing the control method, a control process between a plurality of input and output modules 4 having thousands of relays or controlled units and the central control unit 1 for controlling the input and output modules 4 is applicable. Recognizing the input and output contacts, calculating the input and output addresses, transmitting the address and data through the A / D bus drive, and using the decoder to transmit the select signal to the chip inside the input and output modules, The central control unit 1 reads data from a sensor, which is a device, or transmits and writes control data to a motor or a valve, which is an output device.

However, the conventional method of writing and reading the input and output data through the interface between the PI controller 1 and the input / output module 4, that is, the address / data bus 2 is a microprocessor A and a microprocessor. The driving capability of the IC of the / D bus driver is reduced due to the increase in fanout, thereby limiting the processing speed and capacity.

In addition, the conventional interface circuit method amplifies the signal to a certain level to solve the problem that the signal supplied to each input / output module 4 passing through the address / data bus 2 is reduced in reliability due to external noise or interference. Since the transceiver / receiver 3 is installed, additional cost and maintenance cost increase in the facility, and there is a problem in that an address bus line having a predetermined size or more for controlling the input / output module is provided.

The present invention has been invented in view of the above-described situation, and a plurality of input / output modules having a plurality of input / output ports having a central control unit and a plurality of input / output ports are connected through an address / data bus to build a PI system for facility automation such as steelmaking. In this case, the control signals transmitted by the central control unit via the address / data bus are commonly used in the I / O module, and only the input and output modules of the module mounted on the motherboard of the PSI are recognized. It maintains a one-to-one relationship with input and output modules, and the central control unit can designate each input / output port to read or write data, overcoming the limitations of driving ability due to increased fan out, and eliminating the conventional transceiver / receiver for signal amplification. It is an object of the present invention to provide a control circuit for the input and output module of the PLC control.

1 is a conceptual diagram of an input / output module control circuit of a general PSI controller;

Figure 2 is a block diagram according to an embodiment of the input and output module control circuit of the present inventors PI control,

Figure 3a is a time chart of the control signal according to an embodiment of the input and output module control circuit of the present inventors control panel,

3B is a timing diagram of input and output module control signals according to an embodiment of the input and output module control circuit of the present invention.

Figure 4 is an input module circuit according to an embodiment of the input and output module control circuit of the present inventors PI controller

Figure 5 is an output module circuit according to an embodiment of the input and output module control circuit of the present inventors PI controller.

<Description of the symbols for the main parts of the drawings>

1, 10: central control unit 2, 20: address / data bus

3: Transceiver / Receiver 4, 30: I / O module

11: central processing unit 12: A / D bus drive

13: decoder 31, 41: module decoder

32, 33, 34, 42, 43, 44: bidirectional drive 35 ~ 38: inverting part

45 ~ 48: Register

NOR1, NOR2, NOR1 ', NOR2', NOR3 ': NOR gate

In order to achieve the above object, the input and output module control circuit of the present invention includes a central control unit mounted on the mother board of the PSI and an address / data bus to the central control unit so that the input and output devices of the factory equipment can be controlled. In the circuit for controlling the interface between a plurality of input and output modules connected through,

A module selection input signal IB and an input / output module recognition signal / IOD that recognizes the input / output module 30 so that the central controller 10 operates the input / output module 30. Read signal (/ RD) for reading the input data of the module, write signal (/ WR) for writing control data to the output module, and the input and output module that wants to know and control the type of the input and output module 30 Data to the central control unit 11 for outputting the access signal (AB) to process the input and output data corresponding to the predetermined number of contacts of the 30, and the data to the input and output module 30 or the central control unit (10) Module selection signal (/ MID) by decoding the A / D bus drive 12 for driving the address / data bus 20 and the module selection input signal IB outputted by the central control unit 11 so as to transmit the data. It is configured to include a decoder 13 for outputting

The input module of the input / output module 30 includes a module decoder 31, a plurality of bidirectional drives 32, 33, 34, an inverting unit 35, 36, 37, 38, and a NOR gate (N0R1, NOR2). A module decoder 31 and a plurality of NOR gates N0R1 and NOR2 are applied to the module selection signal / MID and the input / output module recognition signal / IOD to provide the bidirectional drives 32 to 34. The central decoder 10 reads the data of the input module by operating the inverting units 35 to 37 by receiving the access signal AB and the read signal / RD from the module decoder 31. ,

The output module of the input / output module 30 includes a module decoder 41, a plurality of bidirectional drives 42, 43, 44, registers 45, 46, 47, 48, NOR gates (NOR1 ', NOR2', NOR3 '), and a plurality of NOR gates NOR1' and NOR2 'are applied to the module selection signal / MID and the input / output module recognition signal / IOD to bidirectionally communicate with the module decoder 41. The drives 42 to 44 are operated and driven, and the module decoder 41 receives the access signal AB and the write signal / WR to receive the output data of the central controller 10 through the registers 45 to 48. Characterized in writing to the output module.

Hereinafter, a configuration of a preferred embodiment of the input / output module control circuit of the present invention Plc controller will be described in detail.

Figure 2 is a block diagram of an embodiment of the input and output module control circuit of the present invention, PI controller, Figure 4 and Figure 5 is a detailed circuit diagram of the input and output module according to a temporary embodiment of the present invention, respectively. As shown in FIG. 2, the input and output module control circuit of the present invention Plc controller has a plurality of input and output modules 30 connected to thousands of points of input and output devices of a factory facility and connected to an address / data bus. It is connected to the control unit 10. In the present embodiment, the configuration of the present invention is briefly described by installing eight input and output modules. In addition, the central control unit 10 is configured with a microprocessor central processing unit 11, a decoder 13, and an A / D bus drive connected to each other.

As shown in FIG. 4, the input module is composed of a plurality of semiconductor chips, and two NOR gates NOR1 and NOR2 receiving an input signal are connected in series, and the input signal is also connected to the module decoder 31. The output signals of the NOR gates NOR1 and NOR2 are applied to the bidirectional drives 33 and 34, and the output of the module decoder 31 receives the bidirectional drive 32 and the input device. It is connected to be applied to the inverting unit (35 ~ 37) receiving data from the in control equipment, the inverting unit (35 ~ 37) is connected to the bidirectional drive (33, 34) via a photo coupler (not shown) It is. The bidirectional drive 32 is also connected to the bidirectional drives 33 and 34.

As shown in FIG. 5, the output module is composed of several semiconductor chips, and two NOR gates (NOR1 'and NOR2') receiving an input signal are connected in series, and an output terminal of the NOR gate is a module decoder 41. ) And the bidirectional drives 43 and 44 receiving data from the data bus DB, and the terminal 7 (Y7) of the module decoder 41 is connected to the terminal 19 of the bidirectional drive 42 receiving ID information. It is connected. In addition, the output terminals 14 and 15 of the module decoder 41 are connected to the registers 45 to 48, respectively, and the output data of the bidirectional drives 42 to 44 are respectively input to the registers 45 to 48. The reset signal is configured to be input to the CLR terminals of the resists 45 to 48 through the NOR gate NOR3 '.

Hereinafter, with reference to the drawings will be described in detail the operation of the preferred embodiment of the input and output module control circuit of the present invention PI controller.

First, the interface process between the central control unit 10 and the input and output modules 30 will be described in terms of overall flow. When the central control unit 11 in the central control unit 10 recognizes an individual corresponding facility that is an input / output device to be controlled and sends a control output to the corresponding facility, the decoder 31 in the input / output module 30 is provided. In 41), the directions of the bidirectional drivers 32 to 34, 42 to 44 are appropriately selected for the input and the output so that the input and output modules 30 can operate. And the signal output generated to control the equipment in the central control unit 10 is directly output to the input and output module 30 specified by the central control unit 11 of the central control unit 10 of the input and output module 30 The bidirectional drivers 32 to 34 and 42 to 44 control the sensors, switches, or motors or valves connected to the respective input and output contacts. When viewed from the central control unit 10 side, the configuration that can maintain a one-to-one relationship with the input and output module 30 in response to the control signal has an advantage that can solve the problem of the fan out.

On the other hand, the process of reading data by the central controller 10 calculates the address of the input module of the equipment to be controlled and selects a control signal (/ MID), / IOD, When AB01, AB02, / RD) is sent, the chip select signals are enabled through the output terminal of each device inside the input module 30, and the data inputted from the contact or sensor of the corresponding equipment side is transmitted to the central control unit 10. Is read by the central control unit 11).

In addition, based on the input data, the central control unit 11 of the PSI is to write data in order to control the output equipment per line according to the PSI sequence program, and in the writing process, unlike the reading process, the central control unit 11 ) Is sent to the output module with the corresponding address. It can be understood that the other process is developed in the reverse order to the reading process.

Hereinafter, the operation of the input and output modules of FIGS. 4 and 5 will be described with reference to the control signal developed during each cycle period of FIG. 3.

FIG. 3A is a time chart of a control signal according to an embodiment of an input / output module control circuit of the present invention, and FIG. 3B is a timing diagram of an input / output module control signal according to FIG. 3A. As shown in the block diagram of FIG. 2, the central control unit 11 may include a module selection input signal IB, an input / output module recognition signal / IOD, and a module 1 to maintain a one-to-one relationship with the input and output modules 30. A read signal / RD, a write signal / WR, and an accessor signal AB are generated. In this embodiment, it is assumed that eight modules are installed, and thus the module selection input signal IB is generated by IB0, IB1, and IB2. When the decoder is decoded, eight modules mounted on the motherboard of the PSI may be selected. In addition, the accessor signal AB is generated to AB01 and AB02 to drive the module decoders 31 and 41 installed in the input and output modules 30.

Among the control signals, IB0, IB1, and IB2 are input to the decoder 13 and output as / MID0 to MID7 signals.

The / MID signal is a module selection signal for selecting various types of modules, such as a communication module including an input / output module 30 mounted on a motherboard, a special function module, and the like.

The / IOD signal is an input / output module recognition signal that detects whether the module mounted on the motherboard is an input / output module among several modules, and uses a different signal in the same place as the communication module. Is operated by receiving / IOD signal.

/ RD signal is a read signal used when reading the data of the input module from the central control unit (11),

The / WR signal is a write signal used when the central control unit 11 sends data required for control to the output module.

The AB01 and AB02 signals are applied to the module decoders 31 and 41 of the input and output modules, and the output signals of the module decoders 31 and 41 enable the chip receiving the input of the equipment. The type of input / output module 30 that is used when accessing through the data bus of bits and is mounted on the motherboard, that is, whether it is an input module or an output module or facility characteristics initially set on the I / O card, For example, this signal is also used to find information such as the range of voltage used and whether the facility relay adopts the SCR method.

The interface operation relationship between the central control unit 10 and the input and output module 30, which is a PSI control unit, is divided into three cycles, and FIG. 3A illustrates the control signal used to determine the type of the input and output module 30. Each signal state is shown in a configuration check cycle, a write cycle of a control signal used to control an output module, and a read cycle of a control signal used to control an input module. 3B is a state timing diagram of the control signal for each cycle of FIG. 3A.

The configuration check cycle starts immediately after the power is supplied, and the central control unit 10 reads the types of modules mounted on the motherboard of the PIC at regular scan time intervals. The signal is transmitted to the input and output module 30 in the following process.

1. Inform the modules that the / IOD signal is set to LOW to access only the I / O module.

2. The IB0, IB1, and IB2 signals generated by the central controller 11 output the / MID signal using the decoder 13, and the signals from / MID0 to / MID7 are sequentially turned low so that the module can be selected. do.

3. The / IOD and / MID signals are sent LOW, the / RD is Low, the / WR signal is High, and the AB01 and AB02 signals are High.

When the signal state is applied to the input and output module 30, only the input and output modules of various modules respond. At this time, as shown in FIG. 4, the bidirectional drives 32, 33, and 34 are driven to ID information is read by the central control unit to find out the type of I / O module mounted on the motherboard of PIC. When the input / output module 30 determined on the mother board is determined during the cycle, data is written to or read from the input / output module 30 to control the factory equipment.

Read cycle is a process of reading data from an input module and a control signal is applied to the input module as follows.

1. Inform the module that the / IOD signal is low to access the input module.

2. The central control unit 11 outputs the IB0, IB1, and IB2 signals generated by the decoder 13 using the decoder 13 and sends the / MID signal to be accessed among the signals from / MID0 to / MID7 to LOW. .

3. When / IOD and / MID signals are LOW at the same time, set / RD to Low and / WR to High so that the data inputted from the input module can be read.

At this time, if both of AB01 and AB02 are LOW, the output terminal Y0 of the module decoder 31 is output as shown in FIG. 4 to enable the inverting units 35 and 37 to generate 16-bit data from input data DATA00 to DATA15. If AB01 is High and AB02 is LOW, the output terminal Y1 of the module decoder 31 is outputted to enable the inverting units 36 and 38 so that 16-bit data from the input data DATA16 to DATA31 can be read through the data bus. .

Write cycle is a process of writing data from the central controller 10 to the output module, and a control signal is applied to the output module as follows.

1. Inform the modules that the / IOD signal is low to access the output module.

2. The central control unit 11 outputs the IB0, IB1, and IB2 signals generated by the decoder 13 using the decoder 13 and sends the / MID signal to be accessed among the signals from / MID0 to / MID7 to LOW. .

3. When / IOD and / MID signals go low at the same time, make / RD high and / WR low to write data to output module.

At this time, if both AB01 and AB02 are LOW, the enable signal is output from the output terminal Y0 of the module decoder 41 to be input to the terminal 11 of the resists 45 and 47 so that the resists 45 and 47 can be When the input data applied from the central control unit 10 is 16-bit data from OUT00 to OUT15, AB01 is high, and AB02 is LOW, the enable signal is output from the output terminal Y1 of the module decoder 41, and the register 46, The registers 46 and 48 are operated by being input to terminal 11 of 48), and 16-bit data is written from OUT16 to OUT31 by the input data applied from the central controller 10.

Therefore, the central controller 10 and the input / output module 30 of the address to be controlled through the / IOD and / MID are set in a one-to-one relationship, and the AB01 and AB02 signals are also used in the input / output module 30. The contact point of the input and output port to be controlled can be controlled to solve the problem of driving force decrease due to the increase of fan out, and also the control of the corresponding equipment is possible using the signals AB01 and AB02. It is possible to solve the problem of requiring an address busline of a predetermined size or more to control the control.

For reference, the input and output module control circuit of the present invention is not limited to the above embodiment only, it will be apparent that it can be modified within the scope of the detailed description of the present invention and the scope of the claims and drawings.

The input / output module control circuit of the present invention, which has a function as described above, transmits and receives data between the central control unit and the input / output module connected to the thousands of facilities. Since the input and output modules respond to the control signals, the central control unit and the input and output modules can be set in a one-to-one relationship, thus eliminating the need for a separate signal / transceiver / receiver on the address / data bus line. Economical cost savings, and also has the advantage of reducing the power consumption and overcome the limitations of the fan out central control unit.

In addition, since a common circuit for transmitting signals between the central control unit and the input / output module is configurable, the input and output points can be interfaced without difficulty in one module up to 8 points, 16 points, and 32 points.

Claims (1)

In the circuit for controlling the interface between the input and output modules connected to the central control unit mounted on the motherboard of the PIC and the address and data bus so that the input and output devices of the factory equipment is controlled, A module selection input signal IB and an input / output module recognition signal / IOD that recognizes the input / output module 30 so that the central controller 10 operates the input / output module 30. Read signal (/ RD) for reading the input data of the module, write signal (/ WR) for writing control data to the output module, and the input and output module that wants to know and control the type of the input and output module 30 Data to the central control unit 11 for outputting the access signal (AB) to process the input and output data corresponding to the predetermined number of contacts of the 30, and the data to the input and output module 30 or the central control unit (10) The A / D bus drive 12 for driving the address / data bus 20 and the module selection input signal IB outputted by the central controller 11 to decode the module selection signal (/ MID). It is configured to include a decoder 13 for outputting The input module of the input / output module 30 includes a module decoder 31, a plurality of bidirectional drives 32, 33, 34, an inverting unit 35, 36, 37, 38, and a NOR gate (N0R1, NOR2). A module decoder 31 and a plurality of NOR gates N0R1 and NOR2 are applied to the module selection signal / MID and the input / output module recognition signal / IOD to provide the bidirectional drives 32 to 34. The central decoder 10 reads the data of the input module by operating the inverting units 35 to 37 by receiving the access signal AB and the read signal / RD from the module decoder 31. , The output module of the input / output module 30 includes a module decoder 41, a plurality of bidirectional drives 42, 43, 44, registers 45, 46, 47, 48, NOR gates (NOR1 ', NOR2', NOR3 '), and a plurality of NOR gates NOR1' and NOR2 'are applied to the module selection signal / MID and the input / output module recognition signal / IOD to bidirectionally communicate with the module decoder 41. The drives 42 to 44 are operated and driven, and the module decoder 41 receives the access signal AB and the write signal / WR to receive the output data of the central controller 10 through the registers 45 to 48. Input / output module control circuit of the PSI controller, characterized in that it is written to the output module