JP3472891B2 - Control communication system - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In such a control communication system,
Direct wiring between the control controller and output device, or between the control controller and input device, complicates the wiring configuration, requires more work for wiring, and increases the number of wires, resulting in high cost. Will be.

Therefore, as a control communication system with reduced wiring, as shown in FIG. 15, a master station 31 connected to a control controller 30 and an output device such as an actuator or an input device such as various sensors are connected. is provided with a plurality of the slave station 32 ₁ ~32n, and outputs a control signal on-off transmitted from the master station 31 to an output device via the slave station 32 ₁ ~32n, or on-off from the input device The status signal is taken into the slave stations 32 _{1 to} 32n and the master station 3
There is a configuration in which the data is transmitted to one.

[0004]

However, in such a control communication system, when an abnormality occurs in the transmission line due to disconnection, short circuit, noise, etc., the cause of the abnormality can be investigated or the location of the abnormality can be identified. Not easy,
Therefore, there is a drawback that 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, when a transmission line abnormality occurs due to disconnection, short circuit, noise, or the like. In addition, it is an object of the present invention to make it possible to easily detect the cause of the abnormality and to relatively easily identify the place where the abnormality has occurred.

[0006]

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

That is, according to the present invention of claim 1, a master station and a plurality of slave stations are connected in cascade, and a video signal from the master station to each slave station is transmitted.
Output data to the shift clock of the control signal.
In response, by sequentially shifting the slave stations by 1 bit
Transmission from the upstream slave station, which is the master station, to the downstream slave station
Then , the bit data from each slave station to the master station is
1 bit downstream in response to the shift clock of the master signal
A control and communication system for transmitting to said master station by sequentially shifting the upstream side of the slave station from the side of the slave station, the outermost
Even the child station on the downstream side receives the bit transmitted from the parent station.
Is intended to return the bit data subjected to inversion processing in the data to the master station, the master station, the most <br/> the inversion process from the slave station of the downstream bit data subjected not returned
In this case, a detection means for detecting a transmission path abnormality and a display means for displaying an error occurrence according to the detection of the detection means are provided.

According to the second aspect of the present invention, a master station and a plurality of slave stations are connected in cascade , and bit data from the master station to each slave station is transmitted.
In response to the shift clock of the control signal.
By shifting the slave stations one by one, the master station side
Transmitted to the downstream side of the slave station from the upstream side of the slave station is, each
Bit data from the slave station to the master station
Is it a slave station on the downstream side bit by bit in response to the shift clock?
In the control communication system for transmitting to the master station by sequentially shifting the slave station on the upstream side from the
The slave station returns the bit data, which is the bit data transmitted from the master station, to the master station, the bit data being inverted, and the master station performs the inversion process from the most downstream slave station. If the bit data is not returned, the transmission path
First detecting means for detecting an abnormality, the master station,
The second station is provided with a second detecting means for detecting a short circuit by monitoring the signal level of the slave station and a signal line between them, and a display means for displaying an error occurrence in response to the detection of the both detecting means.

According to a third aspect of the present invention, in the control communication system according to the second aspect, the master station includes an operation unit operated to display a cause of the transmission abnormality, and the display means indicates an operating state. A plurality of display elements for displaying, wherein the plurality of display elements include an error display element for displaying an error occurrence, and the operation is performed in a state where the error display element displays an error occurrence state. When the section is operated, at least one display element of the plurality of display elements determines a transmission path abnormality and a short circuit abnormality according to the detection output.
They are separated and displayed .

According to a fourth aspect of the present invention, in the control communication system according to the third aspect, the plurality of display elements are a power source display element for displaying power supply and an operation display element for displaying normal operation. And a power display element
Indicates that the error display element displays the error occurrence status.
If the operating part is operated while the
The transmission line abnormality and short circuit abnormality are distinguished and displayed.
It is a thing .

[0011]

[0012]

According to the first aspect of the present invention, when the data subjected to the inversion process is not returned to the master station due to the occurrence of the abnormality such as the disconnection or the noise, it is detected and the corresponding display is displayed. Therefore, the cause of the abnormality can be quickly grasped by looking at the display content of the display means. Moreover, since an abnormality in the transmission line due to disconnection, noise, etc. occurs between the master station and the slave station that performs the inversion process , try changing the connection position of the slave station to identify the abnormal location. It will be possible to identify.

According to the second aspect of the present invention, when the data subjected to the inversion processing is not returned to the master station due to the occurrence of the abnormality such as the disconnection or the noise, the first detecting means detects it and the display means displays it. When the corresponding display is made, and when a short circuit occurs, the second detecting means detects it and the display means makes a corresponding display. Therefore, the display content of the display means causes an error. The cause can be quickly grasped.

Moreover, since the abnormality of the transmission line due to the disconnection or the noise has occurred between the master station and the slave station to which the inversion processing is performed, by changing the connection position of the slave station, The abnormal place can be specified.

According to the present invention of claim 3 or 4, a plurality of display elements generally provided for displaying a basic operation state, for example, a power supply display element, an operation display element and an error display. Display according to the detection output of the detection means using at least one display element of the display element,
That is, since the display element for displaying the basic operation state also serves as the display of the cause of the abnormality, the cost and the size can be reduced as compared with the configuration in which the display element is separately provided.

[0017]

[0018]

[0019]

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

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

The control communication system of this embodiment comprises a programmable controller 1, a master station 2, and a plurality (four in this embodiment) of slave stations 3 _{1 to} 3 _4.
And the four slave stations 3 _{1 to} 3 ₄ are connected in series via a cable, and the master station 2 side is the upstream side.

In this embodiment, each slave station 3 ₁ except the most downstream slave station (hereinafter also referred to as "end station") 3 ₄
To 3 ₃ are connected with input devices 4 ₁ to 4 ₃ such as various sensors, and the master station 2 controlling the slave stations 3 _{1 to} 3 ₄ is the slave station 3 ₁ to.
The ON / OFF state signals of the input devices 4 ₁ to 4 ₃ transmitted from 3 ₃ are given to the programmable controller 1, and the programmable controller 1 controls a machine tool or the like (not shown) based on the signal. Power is supplied to each of the input devices 4 ₁ to 4 ₃ through the power supply lines of the slave stations 3 ₁ to _{3 3} that are connected in cascade from the master station 1.

The data of the master station 2 is sequentially shifted from the upstream (master station 2) side to the downstream side and transmitted to the slave stations 3 _{1 to} 3 ₄ , and the data of the slave stations 3 _{1 to} 3 ₄ is transferred from the downstream side. The signals are sequentially shifted to the upstream side and transmitted to the master station 2.

In this embodiment, as described above, each slave station 3
_{1 to} 3 ₃ are dedicated to inputs in which only input devices 4 ₁ to 4 ₃ such as various sensors are connected, and in a normal operating state, as will be described later, from input devices 4 ₁ to 4 ₃ Each slave station 3 ₁
The data taken in by ~ 3 ₃ are sequentially shifted and transmitted to the master station 2 side, and the master station 2 gives the data to the programmable controller 1 and also sequentially shifts the data again to make the slave stations 3 ₁ ... 3 is ₄ to repeat the operation of returning to.

[0025] The most downstream slave station 3 _4, the output device such as an input device or actuator is not connected, as described below, in order to detect the abnormality of the transmission path such as disconnection, transmitted from the master station 2 The processed data is inverted and returned to the master station 2.

FIG. 2 is a block diagram showing the configuration of the master station 2 of FIG.

The master station 2 is a data signal terminal connected to a control signal terminal 5 connected to a control signal line and a data signal line for inputting / outputting data between the slave stations 3 _{1 to} 3 _4. 6 and a ground terminal 7.

Further, the master station 2 is connected to the slave station 3 ₁
To 3 to ₄ volume and number registration circuit 8 to register as described later, a data input-output circuit 9 for outputting data data to the input or the programmable controller 1 from the programmable controller 1, the data of the end station 3 ₄ End station check register 10 as first detecting means for monitoring, and input / output register 11 for holding data
And a control circuit 1 for controlling the transmission by generating a control signal composed of a shift clock for sequentially shifting commands and data for controlling the slave stations 3 _{1 to} 3 _4.
2, a synchronization circuit 13 for synchronizing each block, and a control signal output circuit 14 for outputting a control signal.
If, the input-output circuit 15 for inputting and outputting data to and from the slave station 3 ₁ to 3 _4, and the short-circuit detecting circuit 40 as a second detecting means for detecting a short circuit of the wiring, the basic functions of the master station 2 and A display unit 41 for displaying an error cause, which will be described later, and a reset switch 42 that is operated to know the cause of the error when the error occurs are provided.

[0029] In this embodiment, the abnormality of the transmission path due to disconnection or noise between the master station 2 and the end station 3 ₄ detects by the end station check register 10, also, the master station 2,
The short circuit detection circuit 40 detects a short circuit in the slave stations 3 _{1 to} 3 ₄ and the wiring between them.

That is, the end station check register 10
Is to check that the data transmitted from the master station 2 is inverted and returned by the end station 3 ₄ .
When inverted data from the end station 3 ₄ is not returned, the control circuit 1 as a line failure due to disconnection or noise or the like between the master station 2 and the end station 3 ₄
2 gives the detection output.

Further, the short circuit detection circuit 40 detects the short circuit by monitoring the signal levels of the control signal line and the data signal line, and when the short circuit is detected, the control circuit 12 is provided with a detection output.

The display unit 41, whose display is controlled by the control circuit 12, supplies power (POWER OU) in order to display the basic operating state, as shown in FIG.
Power supply display LED 43 that displays T) and normal operation (RU
N) an operation display LED 44 for displaying that
Error display LED45 that displays the occurrence of an error (ERR)
And have. In addition, in FIG. 3, each display LED 43,
The lighting or extinguishing state in each state of 44 and 45 is shown.

When the power is supplied and the device is operating normally, the control circuit 12 controls the operation shown in FIG.
As shown in, the power supply display LED 43 and the operation display LED 44 are turned on and the error display LED 45 is displayed.
Is off.

When the control circuit 12 receives a detection output from the end station check register 10 or the short circuit detection circuit 40, the control circuit 12 notifies the power source of the display unit 41 as shown in FIG. LED 43 for operation and LED 44 for operation display are turned off, and LE for error display is displayed.
Turn on D45.

As a result, the user operates the reset switch 42 as the operation unit in order to know the occurrence of the abnormality and to grasp the cause of the abnormality. The control circuit 12 responds to the operation of the reset switch 42 by
When the output is the detection output from the end station check register 10, that is, when there is an abnormality due to disconnection or noise, as shown in FIG.
3 is turned on, and when the output is the detection output from the short circuit detection circuit 40, that is, when there is an abnormality due to a short circuit, as shown in FIG.
Do not turn on 3 and leave it off.

Therefore, when the user operates the reset switch 42 to turn on the power supply display LED 43, the user can know that there is an abnormality due to disconnection, noise, or the like.
If the power display LED 43 does not light up, it can be known that there is a short circuit.

As described above, when an abnormality occurs in the transmission line due to disconnection, short circuit, noise, etc., the error display shown in FIG. 3B is displayed, so that the user can immediately know the occurrence of the abnormality. Then, when the user operates the reset switch 42, depending on the cause of the abnormality, as shown in FIG.
Since the display shown in (C) or FIG. 3 (D) is displayed, the user can easily understand the cause of the abnormality, and as a result, the work of returning to the normal operating state is quicker than in the conventional example. You can do it.

In this embodiment, by operating the reset switch 42, the display is made according to the cause of the abnormality. However, as another embodiment of the present invention, the reset switch 42 is omitted and an error is displayed. It is also possible to add a display element and, when an error occurs, turn on the error display element according to the cause.

Further, in this embodiment, the display according to the cause of the abnormality is performed by turning on or off the power supply display LED 43 when the reset switch 42 is operated. However, instead of the power supply display LED 43 or the power supply display is performed. In addition to the display LED 43, other display LEDs 44 and 45 may be used.

Furthermore, not only turning on or off,
You may display according to the cause of abnormality by blinking display.

Further, in this embodiment, the short circuit detection circuit 40
However, the short-circuit detection circuit 40 may be omitted in another embodiment of the present invention.

Up to eight slave stations can be connected to the master station 2 of this embodiment, and the input / output register 11 has an 8-bit configuration so as to hold 1-bit data of each slave station.

The command transmitted from the master station to each slave station is
Send data from the master station side to the slave station side, send data from the slave station side to the master station side, output the slave station data to the output device connected to the slave station, and connect to the slave station. There are four types of data input from existing input devices to the slave station.

FIG. 4 shows slave stations 3 ₁ to ₃ 3 other than the end station 3 _4.
3 is a block diagram showing the configuration of FIG.

The slave station 3 ₁ to 3 _3, the master station 2 or the upstream side of the slave station 3 ₁ to 3 _second control signal lines, data signal lines and respectively connected thereto a control signal terminal 16u to the ground line, the data signal In addition to having a working terminal 17u and a ground terminal 18u, each terminal 16d, 17d, 18d is connected to the corresponding line of the slave stations 3 _{2 to} 3 ₄ on the downstream side.

Further, the slave stations 3 _{1 to} 3 ₃ are input latch circuits for latching on / off state signals from the input devices 4 ₁ to 4 ₃ such as various sensors and operation signals of the check switch 27 for confirming the operation to be described later. 20, the upstream and downstream input / output circuits 21u and 21d, 1-bit shift registers 22 _{1 to} 22 ₃ to which data is written or read via the input / output circuits 21u and 21d, and the shift register 22
An output latch circuit 24 for latching the contents of _{1 to} 22 ₃ via the input / output circuit 21d and outputting them to an output device such as the display LED 23 or an actuator, and a control signal from the master station 2 are input to the shift register Two
And a controller 25 for controlling the 2 _{1-22 3,} the shift register 22 ₁ to 22 _3, in conjunction with commands from the controller 25 is made to be able to switch the input and output direction.

[0047] Figure 5 is a block diagram showing the configuration of the end station 3 _4, portions corresponding to FIG. 4, the same reference characters.

[0048] The end station 3 ₄ is not provided with a terminal and an input latch circuit output devices such as an input device or an actuator such as various sensors are connected, the output of the output latch circuit 24 through an inverter 26 upstream It is adapted to be applied to the input / output circuit 21u on the side. Other configurations are similar to those of the other slave stations 3 _{1 to} 3 ₃ .

In the control communication system of this embodiment, when data is transmitted from the master station 2 to the slave stations 3 _{1 to} 3 ₄ , the data in the input / output register 11 of the master station 2 responds to the shift clock of the control signal. 1 bit at a time from the upstream slave station to the downstream end station 3 ₄ in sequence, and conversely, when transmitting data from the slave stations 3 _{1 to} 3 ₄ to the master station 2, each slave station 3 4 _{1 to} 3 ₄ shift registers 22 ₁ to 2
2 ₄ data, and transmit the output register 11 of the master station 2 by sequentially shifted from the downstream side to the upstream side.

6 and 7 are timing charts showing the state of this transmission. FIG. 6 shows the master station 2 to the slave station 3.
7 shows the control signal lines of the slave stations 3 _{1 to} 3 ₄ and the data signal lines on the upstream and downstream sides when transmitting data to _{1 to} 3 ₄ , and FIG. 7 shows the slave stations 3 _{1 to} 3 ₄ to the master station. 2 shows the signals of the respective signal lines of the slave stations 3 _{1 to} 3 ₄ when transmitting data to _No. 2.

When data is transmitted from the master station 2 to the slave stations 3 _{1 to} 3 ₄ , in response to the shift clock of the control signal of FIG. 6A, the upstream side shown in FIG. Input data is shifted bit by bit and is output to the downstream side as shown in FIG. 6 (C).

When data is transmitted from the slave stations 3 _{1 to} 3 ₄ to the master station 2, in response to the shift clock of the control signal of FIG. 7A, the downstream shown in FIG. The input data from the side is shifted bit by bit, as shown in FIG.
As shown in (C), it outputs to the upstream side.

In this embodiment, in order to automate the registration of the numbers of the slave stations 3 _{1 to} 3 ₄ and to eliminate the work of setting the address numbers of the slave stations and the work of registering the numbers, the following configuration is adopted. .

FIG. 8 shows the input / output register 11 of the master station 2 and the slave stations 3 _{1 to} 3 ₄ for explaining the procedure for registering the number of units.
1 is a diagram showing 1-bit shift registers 22 _{1 to} 22 ₄ .

First, when the system is started up, such as when the power is turned on, the master station 2 as shown in FIGS.
“1” is input to each bit of the 8-bit input / output register 11.

Next, the 8-bit data of the input / output register 11 is transferred to the upstream side in synchronization with the eight shift clocks following the command to transmit the data of the master station 2 to the slave stations 3 _{1 to} 3 ₄ . Are sequentially shifted to the downstream side and are input to the 1-bit shift registers 22 _{1 to} 22 ₄ of the respective slave stations 3 _{1 to} 3 ₄ as shown in FIG.

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 data of the slave stations 3 _{1 to} 3 ₄ are transferred to the downstream side. Are sequentially shifted to the upstream side and are input to the 8-bit input / output register 11 of the master station 2 as shown in FIG.

In this embodiment, four slave stations 3 _{1 to} 3 ₄ are connected to the master station 2 to which a maximum of 8 slave stations can be connected, so that it is shown in FIG. respect as in the 8-bit data for all the high level transmission, from the slave station 3 ₁ to 3 _4, that only 4 bits sent back data the high level as shown in FIG. (D) become.

As shown in FIG. 9, the master station 2 shifts the shift clock shown in FIG. 9A in the high level period of the data shown in FIG. 9B returned from the most upstream slave station 3 ₁ . The number of slave stations 3 _{1 to} 3 ₄ is grasped and registered in the number registration circuit 8, and the end station is arranged on the most downstream side. It recognizes that the eye slave station is the end station 3 ₄ , and thereafter, the data corresponding to this slave station 3 ₄ is given to the end station check register 10, and the data returned from the end station 3 ₄ is always inverted. Monitor whether or not it has been done.

As described above, at the time of system startup such as power-on, predetermined data is transmitted from the master station 2 to the slave station 3.
_{1 to} 3 ₄ , and the master station 2 obtains and registers the number of units based on the data returned from the slave stations 3 _{1 to} 3 ₄ , so that the address number setting work and registration are performed as in the conventional example. No need to set the number of units.

In this embodiment, the predetermined number of data is transmitted from the master station 2 and the number of units is calculated based on the data returned from the slave stations 3 _{1 to} 3 _4. However, as another embodiment of the present invention, For example, when starting up the system, each slave station 3 ₁ ~
Input "1" into the shift registers 22 _{1 to} 22 ₄ of 3 ₄ ,
The data of the slave stations 3 _{1 to} 3 ₄ may be transmitted to the master station 2 in accordance with the eight shift clocks, and the master station 2 may determine the number as in the above.

In the above-described embodiment, the high level data is used as the predetermined data and the positive logic is used. However, as another embodiment of the present invention, the low level data is used as the predetermined data and the negative data is used. It may be configured by logic.

Next, a normal operation procedure after the registration of the number of vehicles is completed as described above will be described with reference to FIG.

[0064] In this embodiment, first, the input device ₄₁ to ₃
A command to input the ON / OFF state signal of _{No. 1} to each slave station 3 _{1 to} 3 ₄ is transmitted, and accordingly, for example, FIG.
As shown in, each of the slave stations 3 _{1 to} 3 ₃ fetches the data of the input device into the 1-bit shift registers 22 _{1 to} 22 ₄ via the input latch circuit 20 as an input unit. At this time, the end station 3 ₄ does not have an input latch circuit, and the data in the shift register 22 ₄ remains unchanged. Next, in synchronism 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 converted into the data shown in FIG. The data is transmitted to the input / output register 11 of the master station 2, and the master station 2
The transmitted data is output to the programmable controller 1.

Next, the data of the master station 2 is transferred to the slave station 3 ₁ through 3 ₄
In synchronization with the eight shift clocks subsequent to a command and event transmission, as shown in FIG. (C), to return the data input and output register 11 to the slave station 3 ₁ to 3 _4, slave station 3 ₁
In response to a command and should output a to 3 ₄ data, each slave station ₃ 1 to 3 ₄ to the output latch circuit 24 to data of the shift register ₂₂ 1 to 22 ₄ as shown in FIG. (C) Output and latch. In this embodiment, since the output device is not connected, the display LED 23 remains on or off depending on the data.

Therefore, the on / off state of the input devices 4 ₁ to 4 ₃ can be grasped by the display LED 23, and
Depending on the off state of the input device ₄₁ to _3, the display LE
By confirming that D23 is turned on or off, it can be confirmed that the data transmission between the master station 2 and the slave stations 3 _{1 to} 3 ₃ is normally performed.

The end station 3 ₄ latches the data of the shift register 22 _{4 in} the output latch circuit 24 in response to the command to output the data of the slave station.
As shown in the block diagram of FIG. 5, the latched data is supplied to the shift register 22 ₄ via the inverter 26, whereby the data in the shift register 22 ₄ is transferred as shown in FIG. It will be reversed.

[0068] Then, again, similar to FIG. (A), captures the data of the input device ₄₁ to ₃ in the shift register ₂₂ 1 to 22 ₃ of each slave station ₃ 1 to 3 _3, as described above Is repeated. Incidentally, when the captured data of the input device ₄₁ to _3, the data in the shift register 22 ₄ end station 3 ₄ will remain in the inverted data shown in FIG. (D). This inverted data is also used for each other slave station.
3 ₁ to _{3 3} data of the shift registers 22 _{1 to} 22 ₃
In both cases, the slave stations on the upstream side are sequentially shifted to input / output records of the master station.
It is transmitted to the register 11.

In this way, the end station 3 ₄ inverts the data from the master station 2 and sends it back to the master station 2, and the master station 2 always inverts the data from the end station 3 _4. The transmission is monitored, and when the inverted data is not transmitted, it is determined that there is an abnormality in the transmission path due to disconnection or noise, and the above-mentioned error display is performed on the display unit 41.

[0070]

In this embodiment, in order to easily confirm whether or not the data transmission between the slave stations 3 _{1 to} 3 ₄ and the master station 2 is normally performed, the slave stations 3 _{1 to} 3 3 can be easily confirmed. _The check switch 27 is provided at ₄ , and the display LED 23 for displaying data from the master station 2 is provided at 4.

Therefore, in order to confirm whether or not the data transmission is normally performed, the input devices 4 ₁ to 4 ₃ connected to the slave stations 3 _{1 to} 3 ₄ to be confirmed are turned off. First, the check switch 27 is operated. As a result, the high-level monitor data is fetched into the 1-bit shift registers 22 _{1 to} 22 ₄ and transmitted to the master station 2 according to the above-described operation, and the master station 2 returns the data and shifts the data. Given to registers 22 _{1 to} 22 ₄ ,
The high level data of the shift registers 22 _{1 to} 22 ₄ is latched by the output latch circuit 24 and the display LED 23
Will light up.

Therefore, when the check switch 27 is operated to turn on the display LED 23, it can be determined that the LED is normal.

Here, when the abnormality of the transmission line due to the disconnection or noise is detected, the specification of the abnormal portion will be described.

First, when an abnormality due to disconnection or noise is detected by the end station check register 10, FIG.
The error display shown in FIG. 3B is displayed, and when the user operates the reset switch 42 in order to know the cause of the abnormality, the power display LED 43 is displayed as shown in FIG. 3C.
Lights up, and the user can know that there is an abnormality due to disconnection or noise.

[0076] Thus, the user can know that the abnormality due to disconnection or noise between the slave station 3 ₄ on the most downstream side and the master station 2 has occurred. Therefore, in order to identify the abnormal portion, the connection position of the end station 3 ₄ to return to invert the data from the master station 2 changes to the upstream side. For example, disconnect the _third slave station 3 ₃ from the master station 2 and connect the end station 3 ₄ to operate it. Also in this case, if an abnormality due to disconnection or noise is detected, the master station 2 and the master stations 2 to 3 are detected.
An abnormality has occurred with the second slave station, and if no abnormality is detected, there is an abnormality between the third slave station from the master station 2 and the most downstream slave station. become.

[0077] Thus, to try to change the connection position of the remote station 3 ₄ to return data inversion process to the from the master station 2 will be able to determine where the relative ease abnormal.

In the above embodiment, the case where only the input devices 4 ₁ to 4 ₃ such as various sensors are connected to the respective slave stations 3 _{1 to} 3 ₃ for input only is explained, but another embodiment of the present invention. as a sub-stations 3 ₁ to 3 ₃ to the actuator or air valve or the like output device only connected when the output-only and each slave station 3 ₁ to 3 ₃ to an input device or output device is connected the output combination of The case will be described.

Since the transmission procedure is different between the input only, the output only and the input / output mixed, the manufacturer or the user operates the setting unit (not shown) of the master station 2 to input only, output only or mix the input and output. One of these is to be initialized. Further, in any case, the registration of the number of slave stations is the same as that in the above-mentioned embodiment, and therefore its explanation is omitted.

FIG. 11 is a diagram corresponding to FIG. 10 in the case of output only.

First, a command for inputting the data of the input latch circuit 20 to each of the slave stations 3 _{1 to} 3 ₃ is transmitted, and in response thereto, as shown in FIG. ₁ to ₃
Is a command to fetch the data of the input latch circuit 20 to which the input device is not connected to the 1-bit shift registers 22 _{1 to} 22 ₃ respectively and to transmit the data of the slave stations 3 _{1 to} 3 ₄ to the master station 2. In synchronism with the eight shift clocks following, the captured data is transmitted to the input / output register 11 of the master station 2 as shown in FIG.
As shown in FIG. 2C, the on / off control signal from the programmable controller 1 is loaded into the input / output register 11.

Next, in synchronization with the eight shift clocks following the command to transmit the data of the master station 2 to the slave stations 3 _{1 to} 3 ₄ , as shown in FIG. transmitting the data of the register 11 to the slave station 3 ₁ to 3 _4, slave station 3 ₁ to 3 ₄
Each slave station 3 ₁ according to the command to output the data
To 3 _4, as shown in Fig. 2 (E), and outputs the latched data in the shift register 22 ₁ to 22 ₄ to the output latch circuit 24 to an output device such as an actuator. The end station 3 ₄ inverts the data in the shift register 22 ₄ in response to the command to output the data from the slave station.

After that, the data of the input latch circuit 20 is again fetched into the shift registers 22 _{1 to} 22 ₃ of the respective slave stations 3 _{1 to} 3 ₃ and the same operation as described above is performed, as in the case of FIG. It repeats.

FIG. 12 is a diagram corresponding to FIG. 10 in the case of mixed input and output. In this embodiment, input devices are connected from the upstream side to the first and third slave stations 3 ₁ and 3 _3. The output device is connected to the _second slave station 3 ₂ .

First, a command for inputting the data of the input latch circuit 20 to each of the slave stations 3 _{1 to} 3 ₃ is transmitted, and in response thereto, as shown in FIG. _{1-3 4}
Captures the data of the input latch circuit 20 into the 1-bit shift registers 22 _{1 to} 22 ₃ , respectively, and the slave stations 3 ₁ to
As shown in FIG. 2B, the input data of the master station 2 is input and output in synchronization with the eight shift clocks following the command to transmit the data of 3 ₄ to the master station 2. Then, the master station 2 outputs the transmitted ON / OFF state signal from the input device to the programmable controller 1, and then, as shown in FIG. The control signal is taken into the input / output register 11.

Next, in synchronization with the eight shift clocks following the command to transmit the data of the master station 2 to the slave stations 3 _{1 to} 3 ₄ , as shown in FIG. transmitting the data of the register 11 to the slave station 3 ₁ to 3 _4, in accordance with a command and should output the data of the slave station, the slave station 3 ₁ to 3 _4,
As shown in FIG. 8E, the shift registers 22 ₁ ...
The data of 22 ₄ is latched by the output latch circuit 24 and output to an output device such as an actuator. In addition, end station 3
₄ responds to the command to output the data of the slave station,
The data in the shift register 22 ₄ is inverted.

After that, the data of the input latch circuit 24 is fetched into the shift registers 22 _{1 to} 22 ₄ of the slave stations 3 _{1 to} 3 ₄ again and the same operation as described above is repeated, as in the case of FIG. Of.

Although a maximum of eight slave stations can be connected to the master station 2 in the above-described embodiment, the present invention is not limited to eight stations, but 16 stations and other stations can be connected. May be configured.

In each of the above-described embodiments, the power supply lines from the master station 2 are connected in cascade to connect the slave stations 3 _{1 to} 3 ₄ and the slave stations 3 to each other.
_Although power is supplied to the input devices 4 ₁ to 4 ₃ connected to _{1 to} 3 ₃ , as shown in FIG. 13, when the number of slave stations increases and the distance to the downstream slave stations becomes long, In the slave station on the downstream side, sufficient power is not supplied to the input device or the output device. Therefore, it is necessary to separately provide a power source for each slave station.

Therefore, as another embodiment of the present invention, FIG.
4, the child station 3n on the most downstream side from the parent station 2
In addition to the power supply line VL1 cascade-connected to each other, for example, the power supply line VL2 may be directly connected from the most downstream child station 3n to the parent station 2.

As a result, the double transmission distance can be secured without using a separate power source for each slave station.

Although the end station is provided on the most downstream side in the above-mentioned embodiment, as another embodiment of the present invention, the end station is constructed so that the slave stations can be connected in cascade also on the downstream side thereof.
It may be arranged on the upstream side. In this case, the master station may be configured to be able to set which is the end station, and the master station may select a slave station that is processing data by transmitting data multiple times. It may be configured so that it is recognized as an end station.

Further, the end station may be configured so that an input device or an output device can be connected.

[0094]

As described above, according to the present invention, the abnormality of the transmission line due to the disconnection, the short circuit or the noise is detected and the corresponding display is performed. Therefore, when the abnormality occurs, the cause of the abnormality is caused. Can be quickly grasped, and the abnormality of the transmission line due to disconnection, noise, etc. can be identified by changing the connection position of the slave station to which the inversion process is applied.

According to the present invention, a display element generally provided for displaying a basic operation state, for example, at least one of a power supply display element, an operation display element and an error display element is used for display. Since the element is also used for displaying the cause of the abnormality, the cost and the size can be reduced as compared with the configuration in which the display element is separately provided.

Further, since the slave station which inverts the data and returns the data is the slave station on the most downstream side, the transmission line due to disconnection or noise between the master station and the most downstream slave station is used. It will be possible to detect and display abnormalities.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a master station of FIG.

FIG. 3 is a diagram showing a lighting state of a display LED in each state.

4 is a block diagram of a slave station in FIG. 1. FIG.

5 is a block diagram of the end station of FIG. 1. FIG.

FIG. 6 is a signal waveform diagram when data is transmitted from a master station to a slave station.

FIG. 7 is a signal waveform diagram when data is transmitted from a child station to a parent station.

FIG. 8 is a diagram showing register data when registering the number of vehicles.

FIG. 9 is a signal waveform diagram for explaining determination of the number of vehicles.

FIG. 10 is a diagram showing register data in a normal operation.

FIG. 11 is a diagram showing register data during normal operation according to another embodiment of the present invention.

FIG. 12 is a diagram showing register data during normal operation according to still another embodiment of the present invention.

FIG. 13 is a diagram showing power supply in the embodiment of FIG.

FIG. 14 is a diagram showing power supply according to another embodiment of the present invention.

FIG. 15 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 10 End station check register 40 Short circuit detection circuit 41 Display section 42 Reset switch 43 Power supply display LED 44 Operation display LED 45 Error display LED

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-277397 (JP, A) JP-A-62-81131 (JP, A) JP-A-57-99846 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04B 3/46 H04M 3/24

Claims (4)

(57) [Claims] 1. A master station and a plurality of slave stations are cascade-connected to control bit data from the master station to each slave station.
In response to the signal shift clock, the slave stations are moved one bit at a time
By shifting next, the child on the upstream side, which is the master station side
From each station to the slave station on the downstream side , and control the bit data from each slave station to the master station.
In response to the shift clock of the signal, bit by bit on the downstream side
In the control communication system that transmits to the master station by sequentially shifting the slave stations on the upstream side from the slave station, the slave station on the most downstream side is the bit transmitted from the master station.
And the bit data subjected to inversion processing in Todeta those returning to the master station, the master station, a line failure when the most downstream bit data in which the inversion processing has been performed from the slave station is not returned Ah
Sensing means for sensing Rukoto, response to the detection of said detecting means
And a display means for displaying an error occurrence . 2. A master station and a plurality of slave stations are connected in cascade , and bit data from the master station to each slave station is controlled.
In response to the signal shift clock, the slave stations are moved one bit at a time
By shifting next, the child on the upstream side, which is the master station side
From each station to the slave station on the downstream side , and control the bit data from each slave station to the master station.
In response to the shift clock of the signal, bit by bit on the downstream side
In the control communication system that transmits to the master station by sequentially shifting the slave stations on the upstream side from the slave station, the slave station on the most downstream side is the bit transmitted from the master station.
And the bit data subjected to inversion processing in Todeta those returning to the master station, the master station, a line failure when the most downstream bit data in which the inversion processing has been performed from the slave station is not returned Ah
A first detecting means for detecting Rukoto, the master station, a second detecting means for detecting a short-circuit monitors the slave station and the signal level of the signal line therebetween, the detection of both detecting means
And a display unit for displaying an error occurrence according to the above . 3. The master station includes an operation unit that is operated to display the cause of the transmission abnormality, and the display unit has a plurality of display elements that display an operation state, and the plurality of display elements. The operation element includes an error display element that displays the occurrence of an error, and when the operation unit is operated in a state in which the error display element displays the error occurrence state, at least one of the plurality of display elements is displayed. Abnormality and short circuit of the transmission line depending on the detection output by the display element
The display is made by distinguishing from the abnormality.
The control communication system according to. 4. The plurality of display elements include a power supply display element that displays a supply of power and an operation display element that displays a normal operation, and the power supply display element is a front display element.
Note that the error display element displays the error occurrence status.
When the operation part is operated in the state, the power is transmitted according to the detection output.
A display that distinguishes between a line error and a short circuit error
Control communication system according to claim 3 is.