JPH06244811A - Data transmitter and receiver and discontinuity detecting method for data communication line - Google Patents

Abstract

PURPOSE:To make it possible to easily detect the discontinuity state of a communication line by an arbitrary timing by maintaining a comparatively easy constitution in a data transmitter/receiver transmitting and receiving arbitrary data via a parallel data communication line. CONSTITUTION:A detection signal line 12 is provided in a communication line 18 and the remaining signal lines are set to a high level state, interlocking the inversion of a detection signal to be transmitted via a detection signal line 12 to a detection level side in a data transmitter 20 side. In a data receiver 26 side, the level of the detection signal is always monitored, the level in other signal line is investigated when it is decided that the level becomes a detection level and the information specifying the signal line of a low level is displayed on a discontinuity display part 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel type data transmitting / receiving apparatus and a method for detecting disconnection in its communication line.

[0002]

2. Description of the Related Art Generally, unlike a serial communication line, a parallel data communication line of this type generally has a relatively short distance between devices and is used in a stable electrical condition for data transmission and reception. However, it is not considered to have a special error checking means in advance, and if the communication line is suspected to be broken, for example, a tester is used to inspect the energized state, and it is common to use specialized knowledge. It was target.

[0003]

However, in the case of a data communication line in which the data content changes drastically, the abnormality of the line can be immediately judged, but in the case of transmitting the switch ON operation by the operator through the communication line. Similarly, in the case where the data transmission timing itself is random and occurs only once, the abnormality of the communication line is not only difficult to notice, but may be a fatal defect for the system.

Further, even if some kind of error in the communication line is judged, it is extremely difficult for the operator to recognize the details thereof, and it is almost impossible to deal with it promptly and accurately.

To solve this inconvenience, a method of checking the parity of the data itself to be communicated can be considered.
As the system configuration becomes complicated, error checking is not always performed completely, and it is still difficult to easily know the disconnection position of the communication line.

A method of checking by setting the signal level of all communication lines to a high level is also conceivable, but it is difficult to control the system so as to distinguish it from the data to be transmitted, and the check time is such as when the system is started. The degree of freedom as a system is low, such as limited to a specific period, and stable disconnection detection cannot always be performed.

As a result of considering the above problems, the present inventor has solved all of the above problems by adding one signal line for transmitting / receiving a detection signal to / from a conventional communication line. I found out to do.

The present invention has been made on the basis of the above knowledge, and sets the signal level in each of the remaining lines to a high level state in accordance with the level conversion timing of the detection signal, and the signal level at this time is set to the data level. It is an object of the present invention to provide a disconnection detecting method capable of easily detecting a disconnection state of a communication line at an arbitrary timing while maintaining a relatively simple configuration by performing a check on the receiving side.

A further object of the present invention is to provide a suitable data transmission device and reception device by implementing the above-described disconnection detection method.

[0010]

In order to achieve the above-mentioned object, in the disconnection detecting method according to the present invention, as shown in FIG. 1, a plurality of data signal lines 10 and the data lines 10 are used as communication lines 18. A detection signal line 12 for notifying the inspection time of the signal line 10 is provided.

Here, on the sending side of the data signal DS, the signal level sent through the data signal line 10 is interlocked with the conversion of the signal level of the sensing signal KS sent through the sensing signal line 12 to the sensing level side. Can be set to the same level state such as high level, while the detection signal K described above is received on the receiving side of the data signal DS.
The signal level of each line can be checked in accordance with the timing of conversion of S to the detection level side.

Here, the data transmission device 20 according to the present invention
Is a method for performing the above-described disconnection detection method, and for example, a plurality of input detection units that generate a signal when a predetermined input operation such as an on / off operation of a switch or a change in a detection environment exceeding a set level in a sensor is detected. 14 and
An encoder 16 that generates a parallel data signal corresponding to the detection operation of each input detection unit 14, and a communication line 18 that draws out the data signal output from the encoder 16 to the outside.
It has and.

Further, the above-mentioned communication line 18 includes a plurality of data signal lines 10 and a timing signal line 22 for notifying the valid time of data on the data signal lines 10.
And a detection signal line 12 for notifying the inspection time of each line. The data signal line 10 and the timing are linked with the control unit 24 converting the signal level sent through the detection signal line 12 to the detection level side. All the signal levels sent through the signal line 22 for use can be set to a high level state at the same time.

Further, the data receiving device 26 is connected to the above-mentioned data transmitting device 20 through the communication line 18, and when the detection signal line 12 is in the non-detection level, it is connected through the data signal line 10. Data signal DS sent
And the detection signal line 12
Corresponding to the time of conversion to the detection level side of the communication line 18
Disconnection detection unit 30 for determining the signal level of each line constituting the
And a disconnection display unit 32 capable of transmitting predetermined disconnection information such as a disconnection portion display corresponding to the determination state in the disconnection detection unit 30 to the outside.

[0015]

With the above configuration, when the specific input detection section 14 in the data transmission device 20 performs a predetermined detection operation,
The data corresponding to the detected input position is further encoded by the encoder 16 and transmitted through the communication line 18. The data signal DS is transmitted to the data receiving device 26.
After the time of the detection input to the input detection unit 14 is decoded by the decoder 28 on the side, for example, the input detection unit 1
The corresponding positions of the relays 31 provided by the same number as 4 are turned on.

Here, when a predetermined condition such as a lapse of a set time is achieved, the detection signal KS is sent from the control section 24 to the data receiving device 26 side through the detection signal line 12. At the same time, all the outputs from the encoder 16 are set to the high level state. Therefore, the disconnection detection unit 30 on the data receiving device 26 side confirms that the detection signal KS has been converted to the detection level, and then the communication line 18 Check the signal level on each line of. At this time, when a signal line with a low signal level is confirmed, the disconnection display unit 32 that has received the detection state transmits predetermined disconnection information such as a disconnection portion display for identifying the disconnection position to the outside of the device. To execute.

[0017]

As described above, according to the present invention, the detection signal line 12 is provided in the communication line 18, and the detection signal line 1 is provided.
While the timing is controlled by the detection signal KS sent through 2, the level of the other signal lines is set to a predetermined detection level and the signal level is examined on the receiving side, so that a relatively simple configuration is maintained. As it is, the disconnection state of the communication line 18 can be reliably detected at an arbitrary timing, and the disconnected signal line can be easily specified.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described with reference to FIG. 2, in which a PLC 36 specially configured for sequence control of a target system 38 is connected via communication lines 94 and 18 for display and control. An example of implementation in the control device 34 is shown, but the present invention is not limited to this, and it is needless to say that it can be implemented in substantially the same way when connected to various devices having a data input / output function, whether general-purpose or dedicated. .

[0019]

[Structure of Display Control Device] The display control device 34 is integrated and deployed together with the above-described PLC 36 in an operation console of the target system 38, and the target system 38 is provided.
3, and various display means such as CRT, EL, plasma or liquid crystal for closing an opening 42 which is largely provided at the center of the front face of the main body case 40 as shown in FIG. A reader / writer for arranging a display 44 selected from among the above, a socket 50 to which a plug 48 of a keyboard 46 is detachably attached, and a data input / output operation with respect to an IC card 52 at a position below the display 44. Sockets 54 and are arranged. Both sockets 50
The opening of 54 is removed together with the keyboard 46 after the IC card 52 is once inserted into the socket 54 and the data necessary for the operation is transferred to a nonvolatile memory such as an internal flash EEPROM when the device described later is in operation. In this state, the keyboard 46 is closed to prevent unnecessary access by the keyboard 46, and to protect the inside of the main body case 40 from dust and water.

Inside the main body case 40, the display control circuit 56 shown in FIG.
The front surface of 4 is covered with a transparent touch panel 58, which is substantially similar to the conventional one, in a close contact state, and manual operation during operation of the entire system is enabled via the touch panel 58.

The basic structure of the display control circuit 56 is substantially the same as that of a general personal computer, and a CPU 62, a ROM 64, a RAM 66, and a bus line 60 are used.
The graphic memory 68, the event data memory 70 or the graphic controller 72 is connected to the RO
CP according to the system program stored in M64
U62 performs a predetermined arithmetic operation.

On the other hand, data can be input from the touch panel 58 via the touch panel controller 78, or from the keyboard 46 via the I / O controller 74, and the calculation results stored in the RAM 66 are stored in the graphic memory 68. The image data previously stored in the video RAM 76 is expanded by the graphic controller 72 onto the video RAM 76.
Display corresponding to the contents written in the display 44
Done in.

In addition to the above-mentioned configuration, the display control circuit 56 embodying the present invention enables data input operation by the touch panel 58 via the touch panel controller 78, as well as the event data memory 70 and the graphic. The various data stored in the memory 68 enables display and control operations described later.

The operation surface of the touch panel 58 is electrically divided, and the physical address corresponding to each divided area is output to the touch panel controller 78 simultaneously with the pressing operation on the touch panel 58. Further, the coordinate address corresponding to the coordinate position of the display screen on the display 44 is extracted from the touch panel controller 78, and the CPU 62 performs data processing.

[0025]

[Configuration of PLC] In the PLC 36 to which the above-mentioned display control device 34 is connected, a circuit is unitized for each required individual function, and each unit is connected to the bus line 80 as required.
PL can be added by connecting in parallel via
It has substantially the same configuration as the conventional one that allows the functions achieved as a whole C to be increased or decreased (for example, product number “C2000H” manufactured by OMRON Corporation).

In this embodiment, a CPU unit 81 for controlling the whole PLC, an input unit 83 for directly taking in a detection signal 82 sent from the target system 38, and a target system 38 are provided. An output unit 85 capable of outputting a predetermined control signal 84, a memory unit 86 storing various data,
A computer link unit 87 that enables predetermined data communication with the display control device 34 is provided as a basic unit, and the CPU unit 81 constantly monitors the change state of the input / output means to input data such as new data input. If a change is found, the necessary arithmetic processing is performed and then the memory unit 8
6 is configured to access the corresponding address on the No. 6 and rewrite the contents, or to send the data to the output unit 85.

Further, the storage location of the status information MD input / output to / from the target system 38 such as a conveyor device is a passive device such as a level meter or limit switch provided on the target system 38 to be controlled or displayed. A word device is secured on the memory unit 86 for each component or each active component such as a relay or a motor, and input / output data is for word data such as numerical values, and a word device for bit data such as on / off information. Is set in the memory unit 86 so that the bit device can specify the storage location by addressing. Therefore, by simply accessing an arbitrary word device or bit device in the memory unit 86 from the outside or inside of the PLC 36, the corresponding position of the target system 38 can be controlled or the information on the operation state can be individually retrieved. .

[0028]

[Composition of communication line] Further, the display control device 34 described above.
Is a serial communication of a predetermined standard such as RS-232C and the computer link unit 87 on the PLC 36 side through the communication controller 88 that operates by a communication program that operates with an algorithm specialized for the circuit configuration of the PLC 36 to be connected. It is connected by a line 94, and steadily exchanges urgent data.

In the present invention, in addition to the above-mentioned general-purpose serial communication line 94, a PL is connected via an output controller 90.
C36 side input unit 92 and parallel communication line 18
, And the data signal DS for performing an inching operation such as a fine movement operation of the conveyor in the target system 38 can be directly sent to the PLC 36 side.

As shown in FIG. 4A, the parallel communication line 18 includes N (4 in the present embodiment) data signal lines 10 for transmitting the data signal DS, and the data signal lines 10. One detection signal line 12 for detecting the connection state
With. Therefore, in the input unit 92 of the PLC 36, as will be described later in detail, the level change of each signal line is detected, and the urgent data processing corresponding to the level change is enabled.

[0031]

[Structure of processing instruction word] Display control device 3 for implementing the present invention
4, a base screen 96 whose display contents do not need to be changed as shown in FIG.
Graphic data such as the graphic 98 as shown in FIG. 5B, which is blinked or changes color, is stored in the graphic memory 68 by designating one file number for each required display unit.

On the other hand, among the status information MD indicated by the bit or word device constructed in the memory unit 86 of the PLC 36, necessary information is read into the RAM 66 on the display control device 34 side through the serial communication line 94 at an appropriate time. The content specified by the event name of each processing instruction word W is read out intermittently at every minute time, and the processing instruction word W as illustrated in FIG. 6A is stored in advance in the event data memory 70. PLC read out the operation of
By executing the operation while referring to the state information MD on the 36 side, a display operation that changes in response to a change in the contents of the bit device or the word device on the PLC 36 side is performed.

That is, the basic structure of the processing instruction word W is
As shown in FIG. 6A, the file number F of the base screen on which the display control operation is to be executed, the event name N specifying the operation content to be executed on the base screen, and the execution event are referred to. One or a plurality of pieces of reference information d are provided as a set, and as many processing instruction words W as the number of events to be executed on each base screen are stored in the event data memory 70. .

For example, the processing instruction word WL shown in FIG.
File number F1 in the graphic memory 68 in advance.
The base screen 96 as shown in FIG. 5A stored as
A switch-shaped graphic 98 as shown in FIG. 5B stored as the file number F2 is synthesized and displayed as shown in FIG. 5C, and the display color of the graphic 98 is changed to PLC.
The display number is changed according to the value of a specific bit device on the 36 side, and the file number F of the base screen 96 is changed.
1, an event name N1 starting from "L" for specifying the call of the graphic 98, a file number F2 for specifying the graphic 98 to be called, an address A1 of a bit device on the PLC 36 side referred to when the graphic 98 is displayed, and a bit device of "1" , Or “0”, the coordinate information X1 on the display 44 for displaying the graphic 98.

On the other hand, the processing instruction word WT shown in FIG. 6C, contrary to the above, interlocks with the pressing operation on the touch panel 58 and sends predetermined data to the PLC 36 side to send the PLC 3
6 or a target system 38 connected thereto, which is capable of controlling the file number F1 of the base screen 96, the operation name of the touch panel 58, for example, the event name N2 starting from "T", and the input from the touch panel 58. Input coordinate range X2 on the display 44 for validating the operation, address A2 of the device on the PLC 36 side where data should be written in conjunction with the operation of the touch panel 58, momentary bit in which data writing is limited to the pressing time of the touch panel 58 It is composed of an operation mode M2 that specifies writing or word writing for overwriting an absolute value, and word data to be written or bit position information M3 in the word.

In the present embodiment, the processing instruction word WT constructed for the touch panel 58 is further expanded to provide a processing instruction word Wt dedicated to the inching operation. That is,
For example, "Ti
By designating "hX" (where X is a number), the first letter "T" indicates that it is a processing instruction word for the touch panel (hereinafter referred to as "touch tag"), and the next "ih" Indicates that it is a touch tag for inching operation (hereinafter referred to as “inching tag”), and the number “X” added at the end indicates the control device number on the PLC 36 side.

The device number is matched with the line number of the data signal line 10 in the parallel communication line 18 in advance, and the signal level in the corresponding data signal line 10 is changed only by designating the device number. is doing.

Therefore, from the event name N3 and the effective input coordinate range X2 on the touch panel 58, as shown in FIG.
The touch panel 58 for the corresponding coordinate position as shown in FIG.
Exactly in conjunction with the operation timing of the above switches A to D, the parallel communication line 18 rather than the serial communication line 94 side
Then, the corresponding signal line of the line 18 is sent to the PLC 36 side in the “H” level state, and it is possible to send the data signal DS to the PLC 36 side without the access period to the touch panel 58 and the time delay.

[0039]

[Operation of Display Control Device] Next, according to the flow charts shown in FIGS. 7 to 10, the operation of the display control device 34, in particular, the touch panel 58 is used to perform the inching operation of the conveyor of the target system 38 while disconnecting the communication line 18. A method of simultaneously performing detection will be described.

First, in step 100 of FIG. 7, the power switch is turned on to start the display control device 34, and in step 101, predetermined data communication is performed with the PLC 36 side to determine whether the entire system is automatically operated in an online state. A selection is made as to whether or not the display control device 34 is operated to perform the drawing process in the offline state. Usually I
The contents of the non-volatile memory provided for storing data from the C card 52 are initialized at the start of use, and dedicated data as an embedded system is set in both the event data memory 70 and the graphic memory 68. Since it is not, the process moves to the drawing process mode of step 110 and the necessary data setting process is performed.

When the drawing processing mode is entered in step 110 of FIG. 8, it is determined in step 112 whether image data to be stored in the graphic memory 68 or event data to be stored in the event data memory 70 is being created.
It is judged at 11.

The graphic processing performed in step 112 enables a drawing operation that is substantially the same as the processing operation in a general CAD or drawing program. For example, the conventional graphic processing shown in FIG. A base screen 96 on which a figure simulating an operation panel is displayed over the entire screen, and on the base screen 96, a change corresponding to a switch pressing operation is given and displayed.
A movable figure 98 such as a switch shown in (b) is stored in the graphic memory 68 while specifying each other by the file numbers F1 and F2.

When all required figures have been created,
The event data registration work starts. Such work is performed in an interactive manner, and the display control device 34 side judges the content of the input data and prompts for the input of necessary data.
The operator does not need any special knowledge about the program and enables the necessary screen design.
After the event name N to be executed in 3 is input, the content of the event to be executed is determined in step 114 from the initials of the input event name.

For example, since it can be determined that the event name N is a touch tag when the first code is "T", the process proceeds to step 115. Further, if it is judged in this step 115 that the tag is an inching tag, it is urged to move to step 116 and set the effective input area X2 on the touch panel 58 by moving the cursor. Therefore, for example, when the area designation is completed by designating the coordinates of the upper left corner and the lower right corner, 1
Since the contents of the reference information d in one processing instruction word W can be specified, in the next step 117, the event data memory 70
Is stored in. Further, when it is determined in step 118 that the processing instruction words W for all the required events are registered, the process proceeds to step 119 and ends.

On the contrary, when it is determined in step 115 that the tag is a normal touch tag, in step 120, an operation mode M2 for distinguishing between the absolute value input of data and the momentary input of bit data is set, and then in step 121. After setting the address A2 of the device on the PLC 36 side to which the data is output and further setting the bit position M3 of the word data or the bit data to be output in step 122, the process proceeds to step 116 and the same processing as above is performed.

Furthermore, if it is determined in step 114 that the processing instruction word W is other than the touch tag, the process proceeds to step 123, and necessary information setting is performed in substantially the same manner as above.

Next, when it is determined in step 101 of FIG. 7 that the mode is the online mode, the data communication process of step 102 is performed. This communication processing is to take out the status information MD on the PLC 36 side, which is quoted by the processing instruction word W set in the event data memory 70, to the display control device 34 side.
In the processing instruction word W stored in 0, the address of the word device and the bit device of the PLC 36 is extracted from the information included in the processing instruction word W related to the currently displayed base screen F1, and the communication controller 88, the serial Communication line 94 and computer link unit 87
To directly access the memory unit 86 of the PLC 36 to develop the addressed state information MD in the RAM 66.

In parallel with the data communication processing operation, various control processing such as display processing of each event in step 103 and disconnection detection processing of the communication line 18 in step 104 are performed. The display process performs a display operation based on the state information MD extracted in the RAM 66 by the communication process in the process instruction word W stored in the event data memory 70.

Further, when it is determined in step 105 that the touch panel 58 is pushed or released, the data processing of the touch panel 58 starts from step 106 of FIG.

In the touch panel data processing, in step 130, the event data memory 70 is searched based on the input coordinate data sent from the touch panel controller 78, and in step 131, the effective input coordinate range X2 including the corresponding coordinate data is determined. It is determined whether or not the designated touch tag is registered, and if not registered, the process proceeds to step 132 and ends.

When it is determined in step 131 that the touch tag has been registered, the content of the operation mode M2 is determined in step 133, and it is determined that the data writing process is necessary in step 134. Step 13
At 5, the data rewriting process of the corresponding address in the RAM 66 is performed. At the same time, the write data is sent by designating the address of the word device in the PLC 36 via the communication controller 88, and
The state information on the side 6 and the state information on the side of the display control device 34 are made to match.

On the other hand, if the judgment is made at step 134 in FIG. 9 that it is an inching tag, it is judged at step 136 whether the touch panel 58 is pushed or released, and if so, it is outputted to the output controller 90 at step 137. The data signal DS is sent by designating the pin to raise the level of the corresponding communication line 18 without any time delay. On the contrary, if the hand is released from the touch panel 58, in step 138, the above-mentioned data signal DS
Is immediately turned off in the same manner, and the transmission of the data signal DS to the PLC 36 side is stopped.

The present invention is characterized by the procedure of the disconnection detection processing of the communication line 18 in step 104 of FIG. 7 described above.

That is, as shown in the detailed procedure in FIG. 10, an area 37 for storing data corresponding to the connection state of the parallel communication line 18 is stored at a predetermined address in the state information MD on the PLC 36 side as shown in FIG. It is installed like. Therefore, when entering the detection processing routine, first, in step 140, the error flag of the storage area 37 is checked, and when it is determined that an error has occurred in the connection, the corresponding disconnection site data is set in step 141, A display of the disconnection site corresponding to the set data is displayed on the display 44 to prompt the operator to take action.

If it is determined in step 141 that no error has occurred, it is checked in step 142 whether a preset time has elapsed. If "YES", the detection is performed in step 143. The output level of the signal KS is lowered (time t1 in FIG. 4B). After that, step 1
At 44, the data signal DS currently being output is saved, and at step 145, all the data signals DS are simultaneously set to the high level. After maintaining such a state for a predetermined short time, the output signal is returned to the original state in step 146, and the detection signal KS is returned to the high level state at time t3 in step 147, and a series of processing operations are ended.

On the other hand, on the input unit 92 side of the PLC 36, input is made only when it is confirmed in step 151 that the detection signal KS is in the high level state and in step 152 that the error bit of the storage area 37 is not turned on. It is judged that the value of the data signal DS present is correct,
The data acquisition process in step 153 is performed.

When it is determined in step 151 that the detection signal KS is at low level, the level of the data signal DS is checked at time t2 in step 154. At this time,
If it is determined that all the signals including the data signal DS are at the high level, it is determined that there is no abnormality in the connection state of the communication line 18, and therefore, the process returns to step 151 without further action. The above process is repeated.

However, in step 154, the data signal line 1
If it is determined that any one of the 0's is at a low level, a predetermined bit in the error data of the status information MD is turned on in step 155 to check the abnormal connection of the PLC 36 and the display control device 34. Notify me.

FIG. 11 shows another embodiment of the present invention. In this embodiment, the touch switch 14 formed on the touch panel 58 and the data communication line do not correspond one-to-one but are pressed. The position is converted into binary data and is output from the data signal line 10, and further the data signal line 10
A timing signal line 22 is provided for defining the valid period of the data output from. In the present embodiment, the value of the data signal DS is taken as valid at the time t1 which is the rising timing of the timing signal SS, while the detection signal K
Corresponding to the time t2 when S changes, the data signal line 10 and the timing signal line 22 are also set to the high level state so that the disconnection states of all the communication lines 18 can be inspected at the same time. There is.

In this embodiment, for example, TiwX (where X is a number) is prepared as an event name representing a touch tag specialized for encoding output. And
At the time of setting the inching tag shown in step 115 of FIG. 8, while setting the output code to be encoded and output,
In step 137 of FIG. 9, the set output code is designated to send the data signal DS.

Furthermore, FIG. 12 shows the switch 1 as described above.
The case where a plurality of data are transmitted and received in a time-divisional state in series instead of outputting data corresponding to only the pressing time of No. 4 will be exemplified. Also in this embodiment, by setting the signal levels of all the signal lines including the timing signal SS that defines the data read timing in accordance with the output timing of the detection signal KS to the high level state, the communication line The disconnection state of 18 can be detected.

The combination of the PLC 36 and the display control device 34 is not limited to the above, and as shown in FIG. 1, a data transmission device 20 such as a switch block having a mechanical switch group 15 and the switch block. A combination with a data receiving device 26 such as a relay terminal having a relay group 33 connected via the communication line 18 is also possible.

In this embodiment, the data corresponding to the pressed state of the switch group 15 is converted into binary data by the encoder 16 and then sent to the relay terminal 26 through the data signal line 10. On the other hand, on the relay terminal 26 side, the decoder 28 decodes the data signal DS sent through the data signal line 10, and the switch group 15
The relay 31 corresponding to each press switch provided as the input detection unit 14 therein is turned on.

At the same time, the control section 24 sends the detection signal KS to the relay terminal 26 side in accordance with the procedure described above, while the disconnection detection section 30 determines the disconnection state of the communication line 18, and if any abnormality is recognized, it is determined for each signal line. The broken line in the broken line display section 32 including the display means such as a display lamp provided is transmitted to the outside.

The type and number of signal lines included in the communication line 18 can be changed as appropriate. Further, the voltage level of each signal line or the signal level at which the data is valid may be changed as long as the disconnection state of the communication line 18 can be detected. Further, instead of transmitting the data via the communication line between the two devices, the data transmission within the single device or the single processor can be performed in substantially the same manner. Further, the method of coding the data is not limited to the binary conversion, and it goes without saying that the method can be appropriately changed and implemented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing an example in which the present invention is applied to a communication line between a display control device and a PLC.

FIG. 3 is a partially cutaway perspective view schematically showing the outer shape of the display control device.

FIG. 4 is a diagram showing a configuration of a parallel communication line,
(A) is an explanatory view showing an example in which the pressed position on the touch panel and the output line of the signal correspond to each other on a one-to-one basis, and (b) is a waveform diagram showing the detection procedure of the disconnection state.

FIG. 5 is an explanatory diagram showing an example of a screen configuration, including (a)
Is a base screen, (b) is a variable figure, and (c) is a composite screen of both.

6A and 6B are explanatory diagrams showing a basic configuration of a processing instruction word, in which FIG. 6A is a basic configuration, FIG. 6B is a display configuration, and FIG.
(C) each shows the structure for touch panels.

FIG. 7 is a flowchart showing an overall operation procedure in the display control device.

FIG. 8 is a flowchart illustrating an operation procedure of the drawing process in FIG.

9 is a flowchart illustrating a procedure of a data processing operation via the touch panel in FIG.

10 is a flowchart illustrating an operation procedure of disconnection detection processing in FIG.

FIG. 11 is a view similar to FIG. 4 showing another example of the present invention, in which (a) is an explanatory view showing an example in which instruction data for a touch panel is coded, and (b) shows a disconnection state detection procedure. It is a waveform diagram shown.

FIG. 12 is a waveform diagram illustrating a disconnection detection procedure in the case of transmitting and receiving data in a time division state in series, showing still another embodiment of the present invention.

[Explanation of symbols]

 DS data signal KS detection signal SS timing signal MD status information 10 data signal line 12 detection signal line 14 input detection unit 15 switch group 16 encoder 18 parallel communication line 20 data transmission device 22 timing signal line 24 control unit 26 data reception device 28 Decoder 30 Disconnection detection unit 31 Relay 32 Disconnection display unit 33 Relay group 34 Display control device 36 PLC 38 Target system 44 Display 58 Touch panel 66 RAM 68 Graphic memory 70 Event data memory 88 Communication controller 90 Output controller 92 Input unit 94 Serial communication line

Claims (3)

[Claims] 1. A plurality of data signal lines (10) and a detection signal line (12) for notifying the inspection time of the data signal line (10) are provided, and the above-mentioned detection signal line is provided on the transmission side of the data signal DS. (1
The signal level of the detection signal KS sent through 2) is changed to the detection level side so that all the signal levels sent through the respective signal lines can be set to the same level state, while the receiving side of the data signal DS is set. Then, a disconnection detection method for a data communication line, characterized in that the signal level of each line can be checked in accordance with the above-mentioned conversion timing of the detection signal KS to the detection level side. 2. A plurality of input detection units (14) for generating a signal when a predetermined input operation is detected, and each input detection unit (1).
It is a data transmission device comprising an encoder (16) for generating a parallel data signal DS corresponding to the detection operation of 4) and a communication line (18) for drawing out the data signal DS output from the encoder (16). The communication line (18) includes a plurality of data signal lines (10) and a timing signal line (22) for notifying the valid time of data on the data signal lines (10).
And a detection signal line (12) for notifying the inspection time of each line, and further, in conjunction with converting the signal level of the detection signal KS sent through the detection signal line (12) to the detection level side, A data transmission device comprising a control unit (24) capable of simultaneously setting all signal levels transmitted through a data signal line (10) and a timing signal line (22) to a high level state. 3. A data receiving device connected to the data transmitting device according to claim 2 via a communication line (18), wherein the data signal line is at a non-detection level of the detection signal line (12). A decoder (28) capable of decoding the data signal DS sent via (10), and each line constituting the communication line (18) corresponding to the time of conversion of the detection signal line (12) to the detection level side. And a disconnection display unit (32) capable of transmitting disconnection information corresponding to the determination state of the disconnection detection unit (30) to the outside. Data receiving device.