JPH1098420A - Control communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a fault in a transmission line due to a broken line or the like and to easily locate the fault occurrence range in the control communication system where a master station and a plurality of slave stations are connected in cascade and data of the slave stations shifted sequentially are sent to the master station. SOLUTION: A power conduction display LED 11 that is turned out when a broken line takes place in a power line 5 or a ground line is provided to each of slave stations 31 -34 , which is provided with a broken line detection means 12 that detects a broken clock line 7 or a broken data line 8 and a clock broken line display LED 21 and a data broken line display LED 23 which are lighted in response to the occurrence of a broken line in the clock line 7 and the data line 8 based on an output of the broken line detection means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transmitting an on / off state signal from an input device such as a limit switch or various sensors to a control controller or the like, or an on / off control signal from a control controller or the like. And a control communication system suitable for transmitting the same to output devices such as an air valve and an actuator of a machine tool.

[0002]

2. Description of the Related Art In such a control communication system,
If the control controller and the output device, or the control controller and the input device, are individually wired directly, the wiring configuration becomes complicated, the wiring work becomes troublesome, and the cost increases due to the increase in the number of wires. I will use it.

Therefore, as a control communication system with reduced wiring, for example, as shown in FIG. 11, a master station 51 connected to a control controller 50 and output devices such as actuators or input devices such as various sensors are used. a connected plurality of slave stations 52 ₁ ~52n, and outputs a control signal on-off transmitted from the master station 51 to an output device via the slave station 52 ₁ ~52n, or off from the input device there is a constitution of transmitting to the master station 51 takes in the state signal to the slave station 52 ₁ ~52n.

[0004]

However, in such a control communication system, when an abnormality occurs in a transmission line due to disconnection or the like, it is not easy to detect the abnormality and to specify the location where the abnormality has occurred. It takes a long time to return to a normal state.

The present invention has been made in view of the above points, and in a control communication system including a master station and a plurality of slave stations with reduced wiring, a transmission line abnormality due to disconnection or the like has occurred. Be able to detect it,
It is an object of the present invention to easily identify a place where the abnormality has occurred.

[0006]

In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the present invention according to claim 1 is a control communication system in which a master station and a plurality of slave stations are cascaded, and the data of each station is sequentially shifted to an adjacent station for transmission. The station includes a disconnection detecting means for detecting a disconnection of the connection line, and a disconnection display means for displaying the disconnection based on the output of the disconnection detecting means.

[0008] According to a second aspect of the present invention, in the control communication system of the first aspect, the slave station includes an energization display means for displaying power supply.

According to a third aspect of the present invention, in the control communication system of the first or second aspect, the disconnection detecting means is at least one of a data line for transmitting the data and a clock line for transmitting a clock for shifting the data. The disconnection display means performs a display according to the type of the disconnected connection line. According to a fourth aspect of the present invention, in the control communication system according to the second aspect, the disconnection detecting means disconnects at least one of a data line transmitting the data and a clock line transmitting a clock for shifting the data. The disconnection display means controls the display state of the energization display means in accordance with the type of the disconnected connection line.

According to a fifth aspect of the present invention, in the control communication system of the second aspect, the disconnection detecting means connects at least one of a data line for transmitting the data and a clock line for transmitting a clock for shifting the data. The disconnection display means includes a disconnection display element, and controls the display state of the disconnection display element and the energization display means according to the type of the disconnected connection line. The display is performed.

According to the first aspect of the present invention, the slave station includes a disconnection detecting means for detecting a disconnection of the connection line, and a disconnection display means for displaying the disconnection based on the output of the disconnection detecting means. Therefore, disconnection of the connection line can be detected and displayed for each slave station, and the location of the disconnection can be easily specified, thereby greatly reducing the time and labor required for wiring replacement when a disconnection occurs. As a result, it is possible to return to a normal state in a shorter time than before.

According to the second aspect of the present invention, since the slave station is provided with the power supply display means for displaying the presence or absence of power supply, the power supply line or the ground line is broken and the power supply is cut off. Sometimes, it can be displayed, and at the time of setting up the system, it is possible to immediately visually recognize whether or not the connection has been normally made and the power has been supplied.

According to the third aspect of the present invention, the disconnection detecting means detects a disconnection of at least one of the data line and the clock line, and the disconnection display means displays a signal corresponding to the type of the disconnected connection line. Is performed, it is possible not only to easily identify the location of the disconnection, but also to identify the type of the disconnected connection line, thereby further reducing the time and labor required for replacing the wiring when the disconnection occurs. Become.

According to the fourth aspect of the present invention, the same operation and effect as those of the third aspect of the present invention are obtained, and the display state of the energization display means is controlled according to the type of the disconnected connection line. The means can also be used for displaying the disconnection.

According to the fifth aspect of the present invention, the same operation and effect as those of the third aspect of the invention can be obtained, and the display state of the energization display means and the disconnection display element can be controlled to reduce the type of the disconnected connection line. Since the corresponding display is performed, it is not necessary to provide the disconnection display element corresponding to the data line and the clock line individually.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is an overall configuration diagram of a control communication system according to one embodiment of the present invention.

The control communication system of this embodiment includes a master station 2 connected to a programmable controller, not shown, a plurality (in this embodiment, four) slave stations 3 ₁ to
3 ₄ and a master station 2 and four slave stations 3 _{1 to} 3 ₄
Are connected in cascade with four lines of a power line 5, a ground line 6, a clock line 7 and a data line 8 by cables.
The master station 2 side is the upstream side.

[0019] In this embodiment, each child station 3 ₁ to 3 _4,
Input device 41 _{to 4,} such as various sensors and switches are connected, the master station 2 which controls the slave station 3 ₁ to 3 _4, slave station 3 ₁ -
3 gives ₄ a status signal of the input device ₄₁ to the _fourth on-off transmitted from the programmable controller, the programmable controller is based on that, for controlling a machine tool or the like.

[0020] Data of one bit of each input device ₄₁ to ₄ from the captured slave station 3 ₁ to 3 _4, so is sequentially shifted from the downstream side to the upstream side is transmitted to the master station 2 I have.

In this embodiment, each of the slave stations 3 _{1 to} 3 ₄ is exclusively used for input to which only input devices 4 ₁ to ₄ 4 such as various sensors are connected. as described below, the input device ₄₁ to ₄ 1-bit data taken into each slave station 3 ₁ to 3 ₄ are being transmitted are sequentially shifted to the master station 2 side, the master station 2, the data Is given to the programmable controller.

The master station 2 of this embodiment can be connected to a maximum of eight slave stations, and has an 8-bit input / output register so as to hold 1-bit data of each slave station. The master station 2 transmits, via a clock line 7, a command for controlling each slave station and a shift clock for shifting data one bit at a time, and the command is transmitted from the slave station side to the master station side. to case the transmission of data, there are at least two types of requesting the input data of the input device ₄₁ to ₄ connected to the slave station 3 ₁ to 3 ₄ to the slave station 3 ₁ to 3 _4.

The slave station 3 ₁ to 3 _4, 1 bit is provided with a shift register, the data input device 41 _{to 4} connected to the slave station 3 ₁ to 3 ₄ slave station 3 ₁ - this shift register in response to a command and requesting the input to the 3 _4, input device 4 ₁
4 to ₄ on / off state signals, and responds to a command to transmit data from the slave station to the master station.
The data is sequentially shifted and transmitted to the upstream slave station in response to the shift clock from.

FIG. 2 shows data on the data lines on the upstream and downstream sides of the slave station when data is transmitted from the slave stations 3 _{1 to} 3 ₄ to the master station 2.

When transmitting data from the slave stations 3 _{1 to} 3 ₄ to the master station 2, the downstream station shown in FIG. 2B responds to the shift clock of FIG. The input data from the side is shifted one bit at a time and output to the upstream side as shown in FIG.

Next, a normal operation procedure of the communication control system will be described with reference to FIG. In FIG.
Reference numerals 9, 10 ₁ to 10 ₄ denote input / output registers of the master station 2 and shift registers of the slave stations 3 _{1 to} 3 ₄ , respectively.

In this embodiment, first, the input device 4 ₁
Command and requesting the input status signal to 4 ₃ off to each slave station 3 ₁ to 3 ₄ are transmitted, in response thereto, for example as shown in FIG. (A), each slave station 3 ₁ - 3 ₄ the data input device 41 _{to 4,} 1-bit shift register 10 ₁
Take in each of the 10 _4.

Next, in synchronization with the data of the slave station 3 ₁ to 3 ₄ following the eight shift clocks to a command and event transmission to the master station 2, the captured data, as shown in FIG. (B) To the input / output register 9 of the master station 2,
Outputs the transmitted data to the programmable controller.

[0029] Then, again, similar to FIG. (A), the input device ₄₁ to ₄ for each child status signal on-off station 3 ₁ to 3 ₄
Command and requesting the input is transmitted to, in response thereto, for example as shown in FIG. (C), each slave station 3 ₁ to 3 _4,
The data input device 41 _{to 4,} taking each 1-bit shift register 10 ₁ to 10 _4.

Next, in synchronization with the eight shift clocks following the command to transmit the data of the slave stations 3 _{1 to} 3 ₄ to the master station 2, the fetched data is shown in FIG. To the input / output register 9 of the master station 2,
Outputs the transmitted data to the programmable controller.

[0031] Then, again, similar to FIG. (A), captures the data of the input device 41 _{to 4} to each slave station 3 ₁ to 3 ₄ shift register 10 ₁ to 10 _4, as described above The operation of is repeated.

In this embodiment, in order to detect disconnection of the connection lines such as the power supply line 5, the ground line 6, the clock line 7, and the data line 8, and to easily identify the disconnection point, the following method is used. It is composed.

[0033] That is, FIG. 4 is a block diagram showing a configuration of a slave station 3 ₁ to 3 _4, as shown in FIG. 4, each slave station 3 ₁ to 3 _4, the power supply from the master station 2 Power supply display LED 11 as power supply display means for displaying supply of power, and disconnection detection means 1 for detecting disconnection of data line 8 and clock line 7.
And a disconnection display unit 13 for displaying a disconnection according to the type of the disconnected connection line based on the output of the disconnection detection unit 12.

Reference numeral 14 denotes a data transmission processing circuit including the above-described 1-bit shift registers 10 ₁ to 10 ₄ , and the data transmission processing circuit 14 includes, as described above, the input devices 4 ₁ to 4 ₃ . The on / off state signal is fetched, and data is sequentially shifted and transmitted to the upstream slave station in accordance with the shift clock from the master station 2.

The power display LED 11 is connected between the power supply line 5 and the ground line 6 via a load 15.
Lights up when power is supplied from the master station 2, and turns off when power is not supplied,
Therefore, when the power supply line 5 or the ground line 6 is disconnected, the energization display LED 11 is turned off.

When the upstream clock line 7 and the downstream data line 8 are disconnected, the disconnection detecting means 12 provides first and second comparator circuits 16 and 17 for providing high-level outputs, respectively. , Second comparator circuit 1
When the high-level outputs 6 and 17 continue for a predetermined period, the first and second high-level time-up outputs are given.
Second timer circuits 18 and 19 are provided.

Each of the comparator circuits 16 and 17 is, for example, as shown in FIG. 5, for setting the potential thereof to, for example, an intermediate level of the power supply voltage when the clock line or the data line is disconnected. Of the voltage dividing resistor R1,
R2 (R1 = R2) and a window comparator 20 that provides a high-level output when the potential is within a certain range including the intermediate level. When clock or data transmission is performed normally, the clock input or data input indicates a voltage level close to the power supply voltage or ground (GND), and the intermediate level of the power supply voltage continues for a certain period or more. Will not be shown.

Therefore, when the high-level output of the window comparator 20 continues for a predetermined period, that is, when the clock input or data input keeps the potential within a certain range including the intermediate level of the power supply voltage for a predetermined period. Then, the timer circuits 18 and 19 in FIG. 4 provide a high-level time-up output, assuming that the wire is broken.

In the case of the clock line 7, since the high level and the low level are repeated in a normal state and the high level or the low level does not continue for a certain period or more, another embodiment of the present invention is as follows. The window comparator 20 may be omitted.

As shown in FIG. 4, the disconnection display means 13 includes a clock disconnection display LED 21 for displaying the disconnection of the clock line 7 on the upstream side, and a clock disconnection in response to the time-up output of the first timer circuit 18. A first LED lighting circuit 22 for turning on the display LED 21, a data disconnection display LED 23 for displaying the disconnection of the downstream data line 8, and a data disconnection display LED 23 in response to the time-up output of the second timer circuit 19. And a second LED lighting circuit 24 for lighting.

In this embodiment, the power supply display L
The ED 11, the clock disconnection display LED 21, and the data disconnection display LED 23 are illuminated in green, orange, and red, respectively.
3, as visible from the outside, it is disposed at appropriate locations of the slave station 3 ₁ to 3 _4.

In the disconnection display means 13, the clock line 7
Alternatively, when the potential of the data line 8 continues within a predetermined range including the intermediate level of the power supply voltage for a predetermined period, the first LED is turned on by the time-up output of the first timer circuit 18 or the second timer circuit 19. The circuit 22 or the second LED lighting circuit 24 is driven, and the clock disconnection LED 21 or the data disconnection LED 23 is displayed.
Lights up.

Next, a specific example for the display of disconnection due slave station 3 ₁ to 3 ₄ having the above configuration.

[0044] For example, as shown in FIG. 6 (A), when the power supply line 5 or the ground line 6 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, The first and second slave stations 3 ₁ and 3 ₂ on the upstream side are:
Since the power is supplied, the power supply display LED 11 is lit in green, but the third and fourth LEDs on the downstream side of the LED 11 are turned on.
No power is supplied to the second slave stations 3 ₃ and 3 ₄ , and the energization display LED 11 is turned off.

[0045] Thus, the power supply line 5 or the ground line between the third slave station 3 ₃ second child station 3 ₂ energization display LED11 energization display LED11 is lit is not lit 6 It can be seen that is disconnected.

[0046] Also, for example, as shown in FIG. 6 (B), when the data line 8 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the second Child station 3 ₂
Of the data line 8 on the downstream side of the line becomes the potential of the intermediate level of the power supply voltage, which is detected by the second comparator circuit 17 and the second timer circuit 19 of the disconnection detecting means 12 and the data disconnection display means 13 displays the data disconnection. The use LED 23 lights up in red.

Thus, the data disconnection display LED 2
3 it can be seen that the data line between the to have second child station 3 ₂ and the slave station 3 ₃ of the downstream-side lighting is disconnected. In addition,
Since power is supplied to all the slave stations 3 ₁ to 3 _4,
The energization display LED 11 is lit.

[0048] Also, for example, as shown in FIG. 6 (C), when the clock line 7 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the third Child station 3
The potential of the clock line 7 on the upstream side of ₃ and the fourth slave station 3 ₄
The potential of the clock line 7 on the upstream side becomes the potential of the intermediate level of the power supply voltage, which is detected by the first comparator circuit 16 and the first timer circuit 18 of the disconnection detecting means 12 of each of the slave stations 3 ₃ and 3 _4. As a result, the clock disconnection display LED 21 of the disconnection display means 13 lights in orange.

Thus, the LED for displaying the clock disconnection is provided.
A slave station 3 ₃ 21 is lit, it is seen that the clock line 7 between the clock disconnection display LED21 on the upstream side and the slave station 3 ₂ not lit is disconnected. Incidentally, the power supply, because all being supplied to the slave station 3 ₁ to 3 _4, energizing the display LED11 is lit.

In this way, at the time of disconnection, the power supply display L
By turning on or off the ED 11, the clock disconnection display LED 21 and the data disconnection display LED 23, the location of the disconnection and the type of the disconnected connection line can be easily specified, thereby greatly improving the time and labor required for replacing the wiring. Can be achieved.

In this embodiment, although it is detected that the potential of the data line 8 or the clock line 7 is at the intermediate level of the power supply voltage, it is not necessarily required to be at the intermediate level, and the potential can be distinguished from the normal potential. Should be fine.

In the above-described embodiment, the disconnection of both the data line 8 and the clock line 7 is detected and displayed. However, in another embodiment of the present invention, only one of the connection lines is disconnected. May be detected and displayed.

In the above embodiment, the disconnection display LED is used.
Although 23 and 21 are provided individually corresponding to the data line 8 and the clock line 7, as another embodiment of the present invention, a single disconnection display LED is provided to disconnect the data line and the clock line. Depending on the lighting status,
For example, the disconnection of the data line may be displayed by blinking, and the disconnection of the clock line may be displayed by lighting.

The colors of the LEDs 11, 21, 23 are as follows.
The present invention is not limited to the above-described embodiment, and other colors may be used. Further, by providing the LEDs in association with the types of the connection lines, the LEDs may be lit in the same color.

(Embodiment 2) FIG. 7 is a block diagram showing a configuration of a slave station according to another embodiment of the present invention, and portions corresponding to FIG. 4 are denoted by the same reference numerals.

[0056] slave station 3 ₁ to 3 _4, in the same manner as in the embodiment described above, includes a current display LED11 as current display means for displaying the power supply from the master station 2, In addition, this embodiment In the embodiment, the disconnection detecting means 25 for detecting disconnection of at least one of the data line 8 and the clock line 7, and based on the output of the disconnection detecting means 25, the power supply display LED 11 And a disconnection display means 26 for controlling the display state.

The disconnection detecting means 25 includes first and second comparator circuits 16 having the same configuration as that of the above-described embodiment.
17, an OR gate 27 to which the outputs of the comparator circuits 16 and 17 are provided, and a timer circuit 28 to which the output of the OR gate 27 is provided. The disconnection detecting means 25 detects that the potential of the clock line 7 or the data line 8 is within a certain range including the intermediate level of the power supply voltage.
The output of the first comparator circuit 16 or the second comparator circuit 17 becomes high level, whereby the output of the OR gate 27 becomes high level and the timer circuit 2
When the measurement starts at 8 and continues for a predetermined period, it is determined that the clock line 7 or the data line 8 is broken, and a high-level time-up output is given to the break display unit 26.

The disconnection display means 26 supplies a low frequency oscillator 29 to which the output of the second comparator circuit 17 for detecting disconnection of the data line 8 is supplied, and receives an output of the low frequency oscillator 29 and an output of the timer circuit 28. And an ON / OFF switch 31 controlled by the output of the AND gate 30.
1 is provided between the energization display LED 11 and the load 15.

The low-frequency oscillator 29 is in a standby state with its output at a high level. When the potential of the data line 8 is within a certain range including the intermediate level of the power supply voltage, the low-frequency oscillator 29 operates as a low-frequency oscillator. Low frequency oscillation is started by the high level output. When the output of the AND gate 30 is at a high level, the switch 31 is turned off and the energization display L
The ED 11 is turned off, and when the output of the AND gate 30 is at a low level, the ED 11 is turned on and the energization display LED 11 is turned on.

Therefore, when the upstream clock line 7 is disconnected, the output of the first comparator circuit 16 and the output of the OR gate 27 become high level, and the timer circuit 28
Supplies a high-level time-up output, whereby the output of the AND gate 30 becomes high level, turning off the switch 31 and turning off the LED 11 for displaying electricity.

When the data line 8 on the downstream side is disconnected, the output of the second comparator circuit 17 goes high, the low-frequency oscillator 29 starts oscillating, the output of the OR gate 27 goes high, and the timer Circuit 2
8 provides a time-up output, whereby the output of the AND gate 30 repeats high level and low level in accordance with the output of the low frequency oscillator 29, and the switch 31
Is turned on and off, and the energization display LED 11 blinks.

Next, a specific example of the display of the disconnection by the slave station having the above configuration will be described.

[0063] For example, as shown in FIG. 8 (A), when the power supply line 5 or the ground line 6 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, The first and second slave stations 3 ₁ and 3 ₂ on the upstream side are:
Since power is supplied, although current display LED11 is lit, the it third downstream from and fourth child station 3 _3, 3 _4, power is not supplied, LE energization display
D11 is turned off.

[0064] Further, as shown in FIG. 8 (B), when the clock line 7 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the third child potential of the clock line 7 of the potential of the clock line 7 upstream of the station 3 ₃ and fourth child station 3 ₄ on the upstream side becomes the intermediate level of potential of the power supply voltage, disconnection of the slave station 3 _3, 3 ₄ This is detected by the first comparator circuit 16, the OR gate 27, and the timer circuit 28 of the detection means 16, and the output of the AND gate 30 of the disconnection display means 26 becomes high level, and the switch 31
Is turned off, the energization display LED 11 is turned off, and the display state is the same as that in FIG.

[0065] Thus, the power supply line 5 between the third slave station 3 ₃ second child station 3 ₂ energization display LED11 energization display LED11 is lit is not lit, the ground line 6 Alternatively, it can be seen that the clock line 7 is disconnected.

[0066] Also, for example, as shown in FIG. 8 (C), when the data line 8 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the second Child station 3 ₂
Of the data line 8 on the downstream side of the power supply voltage becomes an intermediate level of the power supply voltage, the outputs of the second comparator circuit 17, the OR gate 27, and the timer circuit 28 of the disconnection detection means 25 become high level, and the low level of the disconnection display means 26 becomes low. Frequency oscillator 2
9 starts oscillating, and the output of the AND gate 30 repeats a high level and a low level.
1 turns on and off, and the power supply display LED 11 blinks.

[0067] Thus, the data line 8 during the flashing current display LED11 are second child station 3 ₂ and the slave station 3 ₃ on the downstream side can be seen that disconnected.

As described above, when the power supply line 5, the ground line 6, or the clock line 7 is disconnected, the energization display LED 1
1 can be easily identified by turning on or off, and when the data line 8 is disconnected, the power-on display LE
By blinking of D11, it is possible to easily specify the location of the disconnection and the type of the disconnected connection line.
The time and labor required for replacing the wiring can be remarkably improved.

In this embodiment, since the energization display and the disconnection display are shared by the energization display LED 11, the disconnection of the power supply line 5 or the ground line 6 and the disconnection of the clock line 7 cannot be distinguished. As compared with the embodiment, the number of display LEDs can be reduced.

The other structure is the same as that of the above embodiment.

(Embodiment 3) FIG. 9 is a block diagram showing a configuration of a slave station according to still another embodiment of the present invention.
Parts corresponding to those in FIG. 7 are denoted by the same reference numerals.

[0072] slave station 3 ₁ to 3 _4, in the same manner as in the embodiment described above, includes a current display LED11 as current display means for displaying the power supply from the master station 2, In addition, this embodiment In the embodiment, a disconnection detecting means 32 for detecting a disconnection of at least one of the data line 8 and the clock line 7, and a disconnection display for performing a display according to a type of the disconnected connection line based on an output of the disconnection detecting means 32. Means 33.

The disconnection detecting means 32 includes a first and second comparator circuits 16 and
17, an OR gate 27 to which the outputs of the comparator circuits 16 and 17 are provided, and a timer circuit 28 to which the output of the OR gate 27 is provided. The disconnection detecting means 32 detects that the potential of the clock line 7 or the data line 8 is within a certain range including the intermediate level of the power supply voltage.
The output of the first comparator circuit 16 or the second comparator circuit 17 becomes high level, whereby the output of the OR gate 27 becomes high level and the timer circuit 2
When the measurement starts at 8 and continues for a predetermined period, it is determined that the clock line 7 or the data line 8 is broken, and a high-level time-up output is given to the break display unit 33.

The disconnection display means 33 is provided with an AND gate 35 to which the clock is supplied via the buffer 34 and the output of the timer circuit 28, and a disconnection display LED 36 for displaying the disconnection of the clock line 7 or the data line 8.
And an LED for disconnection display by the output of the AND gate 35
An LED lighting circuit 37 that controls the lighting of the LED 36 and controls the display state of the energization display LED 11 by controlling the switch 31 is provided.

When the downstream data line 8 is disconnected,
One input of the AND gate 35 is supplied with a high-level time-up output from the timer circuit 28, the other input is supplied with a clock via the buffer 34, and the upstream clock line 7 is disconnected. Then, a high-level time-up output is supplied from the timer circuit 28 to one input of the AND gate 35, and a high-level input instead of a clock is supplied to the other input.

Therefore, when the data line 8 is disconnected, the high-level and low-level outputs of the AND gate 35 are supplied to the LED lighting circuit 37 in synchronization with the clock. When the clock line 7 is disconnected, the high-level output is output. The output of the AND gate 35 will be given.

The LED lighting circuit 37 turns on the disconnection display LED 36 in response to a high level input, turns off the switch 31 to turn off the energization display LED 11, and outputs a disconnection display L in response to a low level input.
The ED 36 is turned off, and the switch 31 is turned on to turn on the energization display LED 11.

Therefore, when the data line 8 is disconnected, the disconnection display LED 36 and the power supply display L are synchronized with the clock.
Although the ED 11 and the ED 11 are alternately lit, it generally appears that the ED 11 and the ED 11 are lit at the same frequency. When the clock line 7 is disconnected, the disconnection display LED 36 is turned on, and the energization display LED 11 is turned off.

In this embodiment, the disconnection display L
The lighting color of the ED 36 is orange.

Next, a specific example of the display of the disconnection by the slave station having the above configuration will be described.

For example, as shown in FIG.
When the power line 5 or the ground line 6 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the first upstream side thereof and the second slave station 3 ₁ , 3
_2, since the power is supplied, although current display LED11 is lit in green, the it third downstream from and fourth child station 3 _3, 3 _4, power is not supplied, the energization The display LED 11 is turned off.

[0082] Thus, the power supply line 5 or the ground line between the third slave station 3 ₃ second child station 3 ₂ energization display LED11 energization display LED11 is lit is not lit 6 It can be seen that is disconnected.

[0083] Also, for example, as shown in FIG. 10 (B), when the data line 8 between the upstream side and the second slave station 3 ₂ and the third slave station 3 ₃ is disconnected, the second Child station 3
The potential of the data line on the downstream side of ₂ becomes the potential of the intermediate level of the power supply voltage, which is detected by the second comparator circuit 17, the OR gate 27, and the timer circuit 28 of the disconnection detecting means 32. LE for display
D36 and the power supply display LED 11 are alternately turned on in synchronization with the clock, and the disconnection display LED 36 and the power supply display L
It appears that both ED11 and ED11 are lit.

[0084] Thus, it can be seen that the data line between the lighting disconnection display LED36 is orange to have second child station 3 ₂ and the slave station 3 ₃ on the downstream side is broken.

[0085] Also, for example, FIG. 10 as shown (C), the from the upstream side second child station _{3 2} and the third slave station _{3 3}
When the clock line 7 is broken of between the potential of the third slave station 3 of ₃ upstream of the clock line 7 potential and the fourth slave station 3 ₄ on the upstream side of the clock line 7, the power supply voltage The potential becomes an intermediate level, which is detected by the first comparator circuit 16, the OR gate 27 and the timer circuit 28 of the disconnection detecting means 32 of each of the slave stations 3 ₃ , 3 ₄ , and the disconnection display LED 36 of the disconnection display means 33 is turned on. At the same time, the energization display LED 11 turns off.

[0086] Thus, disconnection display LED36 is lit, and the slave station 3 ₃ energization display LED11 is not lit, the remote station 3 ₂ only energizing the display LED11 of the upstream side is lit It can be seen that the clock line 7 during the period has been disconnected.

In this way, at the time of disconnection, the energizing display L
By turning on or off the ED 11 and the disconnection display LED 36, the location of the disconnection and the type of the disconnected connection line can be easily specified, thereby significantly improving the time and labor required for replacing the wiring.

The other structure is the same as that of the above embodiment.

(Other Embodiments) In each of the above-described embodiments, the display is made by the LED, but as another embodiment of the present invention, the display may be made by a liquid crystal or other display means.

[0090] In the embodiments described above, the master station 2 takes in the state signals off from the input device ₄₁ to ₄
Although the present invention is applied to an input-only system for transmitting data to another station, as another embodiment of the present invention, an on / off control signal from a master station is transmitted to each slave station and output to an output device connected to each slave station. The present invention may be applied to an output-only system, or may be applied to an input / output system.

In each of the above embodiments, the power supply line 5, the ground line 6, the clock line 7, and the data line 8 are cascade-connected. However, as another embodiment of the present invention, the clock is superimposed on the power supply. Power supply line,
The ground line and the data line may be connected in cascade. In this case, for example, in the embodiment of FIG. 9, the first comparator circuit 16, the OR gate 27, and the AND gate 35 can be omitted. The display of FIG. 10C is also omitted for the disconnection display.

In the above-described embodiment, the slave stations are 4
Although the number of slave stations is limited, the number of slave stations may be plural, and it is needless to say that the number of slave stations is not limited to four. Particularly when the number of slave stations is large, the effect of the present invention is remarkable.

[0093]

As described above, according to the present invention, disconnection of a connection line can be detected and displayed for each slave station.
The location of the disconnection can be easily specified, thereby greatly reducing the time and labor required for replacing the wiring when the disconnection occurs, and returning to a normal state in a shorter time than in the conventional example. .

Further, since the power supply display means for displaying the presence / absence of power supply is provided, when the power supply or the ground line is broken and the power supply is cut off, it can be displayed.

Further, since the display according to the type of the disconnected connection line is performed, not only the location of the disconnection can be easily specified, but also the type of the disconnected connection line can be specified.

[Brief description of the drawings]

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

FIG. 2 is a signal waveform diagram when data is transmitted from a slave station to a master station.

FIG. 3 is a diagram showing register data of each station for explanation of operation.

FIG. 4 is a configuration diagram of a slave station in FIG. 1;

FIG. 5 is a configuration diagram of the comparator circuit of FIG. 4;

FIG. 6 is a diagram showing a display state according to disconnection.

FIG. 7 is a configuration diagram of a slave station according to another embodiment of the present invention.

FIG. 8 is a diagram illustrating a display state of the embodiment of FIG. 7;

FIG. 9 is a configuration diagram of a slave station according to still another embodiment of the present invention.

FIG. 10 is a diagram illustrating a display state of the embodiment of FIG. 9;

FIG. 11 is a configuration diagram of a conventional example.

[Explanation of symbols]

2 Master station 3 _{1 to} 3 ₄ Slave station 4 ₁ to 4 ₃ Input device 5 Power line 6 Ground line 7 Clock line 8 Data line 11 LED for power supply display 12, 25, 32 Disconnection detection means 13, 26, 33 Disconnection display means 21 LED for clock disconnection display 23 LED for data disconnection display 36 LED for disconnection display

Claims (5)

[Claims] 1. A control communication system in which a master station and a plurality of slave stations are connected in cascade, and data of each station is sequentially shifted to an adjacent station for transmission, wherein the slave station disconnects a connection line. A control communication system comprising: disconnection detecting means for detecting; and disconnection display means for displaying a disconnection based on an output of the disconnection detecting means. 2. The control communication system according to claim 1, wherein said slave station includes an energization display means for displaying power supply. 3. The disconnection detecting means detects a disconnection of at least one of a data line for transmitting the data and a clock line for transmitting a clock for shifting the data, and the disconnection display means includes: 3. The control communication system according to claim 1, wherein a display is performed according to a type of the disconnected connection line. 4. The disconnection detecting means detects a disconnection of at least one of a data line transmitting the data and a clock line transmitting a clock for shifting the data, and the disconnection display means includes: 3. The control communication system according to claim 2, wherein a display state of said energization display means is controlled according to a type of the disconnected connection line. 5. The disconnection detecting means detects a disconnection of at least one of a data line transmitting the data and a clock line transmitting a clock for shifting the data, and the disconnection display means includes: 3. The control communication system according to claim 2, further comprising a disconnection display element, and controlling a display state of the disconnection display element and the energization display means to perform a display according to a type of the disconnected connection line.