JPH06303281A - I/o terminal system - Google Patents

Abstract

PURPOSE:To provide an I/O terminal system capable of realizing the saving of wiring and securing the flexibility of terminal connection. CONSTITUTION:As a repeater station 25, an extended repeater station 29 is extended in addition to a master repeater station 28, the extended repeater station 29 is connected onto the same communication table 26 as a terminal 27 as a slave station and the extended repeater station 29 and each terminal 27 are provided with an address setting switch 37 and an operation mode setting switch 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an I / O terminal system used in factories and the like, and more particularly to an I / O terminal system devised to save wiring and obtain flexibility in connecting devices.

[0002]

2. Description of the Related Art Generally, I / O terminal systems are
It is composed of a central controller, a relay station, and an I / O terminal. In this type of I / O terminal system, there are two types of I / O terminal connections, one having a fixed number of I / O points and the other having a flexible selection of the number of I / O points.

Further, in the conventional general communication system, in order to save wiring, in the communication from the master station to the slave station, the master station performs data transmission without checking the state of the communication slave station. After confirming the status of the communication slave station, if it is normal,
There is a data transmission method. Also, conventional I / O
In a terminal system, a sensor is installed as an operation monitor of an output device such as a production line, and a signal from this sensor is taken into a controller by a lead wire to check whether the output device is normal or abnormal.

[0004]

In the conventional system described above, the I / O fixed type I / O
Since it can be configured with only a small number of points in order to reduce the waste of points, it is necessary to use the same system in parallel at the time of system upgrade, large number of points, etc.
There was also the problem of increased costs. On the other hand, even the flexible type has a problem in that it has a master I / O interface separately and the hardware is duplicated, resulting in an increase in cost and difficulty in downsizing.

Further, in the method of transmitting data to a communication slave station without confirmation, problems such as data collision and erroneous input / output of I / O occur. Therefore, in order to improve system reliability, a confirmation method is used. It is desirable to take. However, in the method of requesting confirmation, conventionally, the slave station side needs to be started up first, and there is a problem that it is difficult to use at the implementation site. Further, when a sensor is used to confirm the operation of the output device as in the conventional system, there is a problem that a signal line is separately required for each sensor, which does not lead to wire saving.

The present invention has been made in view of the above-mentioned problems, and provides a highly reliable I / O terminal system which realizes wiring saving and secures flexibility of terminal connection. Is intended.

[0007]

Means and Actions for Solving the Problems
The O terminal system is a system including a central controller, a relay station connected to the central controller, and a plurality of terminals connected to the relay station through the same transmission line. ,
An optional repeatable relay station connected to the same transmission line as the terminal is provided, and the additional repeater station and the terminal are provided with address setting means and operation mode setting means, respectively.

In this I / O terminal system, an extension relay station and each terminal are connected as a slave station on the same transmission line, the location is an address setting switch, and the extension relay station and the terminal are distinguished by an operation setting switch. It is performed by ID assignment. Even if an additional relay station is added,
From the perspective of the master relay station (master station), since it is treated as a slave station and connected to the other slave stations on the same line, wiring can be saved.

[0009]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a schematic diagram showing a device configuration of an I / O terminal system of an embodiment of the present invention, and FIG. 2 is a partial block diagram showing a circuit configuration of the I / O terminal system of the embodiment. This system is connected to a relay station 25 by a connection cable 24 to a central control device 21 including a controller unit 22 and a plurality of (four) I / O cards 23, and further, this relay station 25
, 27 are connected to each other by a two-wire communication cable 26 as a slave station group. As the terminal 27, for example, a relay terminal 27 _-1 , a relay terminal 27 _-2 with a failure detection function, a transistor type relay terminal 27 _-3, etc. are connected.

The relay station 5 is a master station 2 as a basic configuration.
8 and the additional relay station 29. In this embodiment, the additional relay station 29 is configured so that up to three stations can be added, and the assigned I / O constant of one station including the master station 28 is 32 points. In this way, a total of 128 I / O points can be controlled. The master station 28 includes a parallel interface 31, a control unit 32, and a communication interface 33, and performs parallel-serial conversion control and overall communication control between each terminal and the extension relay station. The extension relay station 29 includes an address setting switch 37 and an operation mode setting switch 38 in addition to the parallel interface 34, the control unit 35, and the communication interface 36, and performs serial / parallel conversion control, error detection, etc. Communication control is not performed. Similarly, the terminal 27 has a parallel interface 34, a control unit 35, a communication interface 36, an address setting switch 37, and an operation mode setting switch 38.
Is equipped with. The address setting switch 37 and the operation mode setting switch 38 are arbitrarily selected and set by the user, and thus the operation mode setting switch 38 has an ID assigning function. Each extension relay station 29,
In each terminal, the physical location is not determined, and the address setting switch 37 allows the user to
Freely determine the location. However, although the location can be set freely, an ID is given to each device by the operation setting switch 38 in order to distinguish the additional relay station and various terminals.

The additional relay station 29 includes terminals 27, ...
Connected to the same communication cable 26 together with 27,
The master station 28, including the extension relay station 29, controls communication with the terminals 27, ..., 27 via the communication cable 26. In this way, since the extension relay station 29 is also connected to the same communication cable as the terminals 27, ..., 27, the number of I / O points can be increased from 32 to 128 points as needed. Even when measuring, wiring can be saved.

Next, the processing operation when the relay master station (master station) 28 of the embodiment system is started up will be described with reference to the state transition diagram shown in FIG. When the power is turned on, first the hardware and software initial processing is performed (step ST1),
Then, in order to recognize the slave station, each slave station including the extension station is polled for confirmation (step ST2). When there is a response from the slave station and 10 consecutive responses are OK, a configuration check is performed and an operation table is created (step ST
3). If there is no END, a plurality of END stations, and a transmission error that does not match the previous status in step ST2, the slave station recognition is repeated.

After the operation table is created, operation processing is executed for each station that has joined the operation table (step ST
4). The processing up to this point is not much different from the conventional one. When the operation process of the cycle is completed, the presence or absence of the table of additional subscription is checked (step ST5).
Originally, if there is no response, that is, if there is a slave station that has not been started up even though the slave station confirmation polling has been performed in the system configuration, the additional subscription table is available. If there is no additional joining table, the process returns to step ST4 to move to the operation processing of the next cycle. If there is an additional subscription table and a non-subscribed station is confirmed (step ST6), one station is polled to check whether or not there is a response (step ST7). If no response is received, at the beginning of step ST4. Return. And step S
After the operation processing of T4 is completed, next, the additional joining table is advanced by one step to confirm the next unsubscribed station. As a result of confirmation of the non-subscribed station, even if there is a response and there is a status match, the process returns to step ST4 to complete the operation processing, and
The polling for the second time is performed, and the non-subscriber station is confirmed. Consecutive 1
If the status matches 0 times, that is, for 10 cycles, a configuration check is performed (step ST8), and OK.
In this case, the slave station is additionally created in the operation table (step ST9). The non-subscriber station confirmation is performed once in one cycle so that the slave stations that have risen can be sequentially joined without degrading the performance. If there is a region error, a setting error, etc. as a result of the configuration check in step ST8, the slave station is deleted from the additional joining table (step ST10), and the process returns to the beginning of step ST4. The area error is, for example, a case where a terminal is set in an area where an extension station is set. As described above, in this embodiment, every time one cycle of the operation process is completed, that is, the non-subscriber station confirmation and the configuration check process are performed in time division.

FIG. 4 is a block diagram showing a schematic structure of an I / O relay terminal 7 _-2 with a failure detecting function, which is one of the slave stations of the above embodiment. This I / O relay terminal includes a power supply circuit 1, a reset circuit 2, a driver / receiver 3 for transmitting and receiving data to and from a programmable controller, a transmission control circuit 4, and a relay coil output D16 from the transmission control circuit 4. , D17, D18, D19, the output circuit 6 for energizing the relay coils 5 _-1 , 5 _-2 , 5 _-3 , 5 _-4 and the relay contacts 7 _-1 , 7 _-2 , 7 _-3 , 7 _-4 and load circuits 8 _-1 , 8 _-2 , 8 _-3 , 8 _-4 and current detection coils 9 _-1 , 9 _-2 , 9 _-3 , 9 _-4 , and these connected in series each coil 9 _-1, ..., 9 _-4 detects magnetic flux generated, a load circuit 8 _-1, ..., 8 signal indicating the presence or absence of a current of _-4 D0, D1,
Current detection circuit 10 for outputting D2 and D3, and display elements LED3, ..., LED for performing display corresponding to four relays
6 and switches 11 _-1 , ..., 11 _-4 for switching to a mode in which OPEN is not detected. Although the current detection circuit 10 is shown in a single block diagram, the four current detection circuits 10 are independently provided corresponding to the coils 9 _-1 , ..., 9 _-4 . The transmission control circuit 4 has a function of receiving a current detection signal of the load circuit output from the current detection circuit 10, performing logical processing with the output of the relay coil, and determining the presence / absence of a failure. For example, when the output of the current detection circuit is absent even though the relay output is the ON output, the OPEN failure is determined by the logical processing of the transmission control circuit 4. The relay whose failure is detected is the corresponding display element LED3,
The LED 6 flashes and lights, and a signal (corresponding flag) indicating a failure of the relay is sent to the master station 28 and the controller 22 via the driver / receiver 3 and the communication cable 26 of FIG.

[0015]

According to the invention described in claim 1 of this application, the communication master station (relay master station), the communication slave station (terminal), and the communication extension station are arranged on the same communication path. 1) In the conventional fixed I / O point number system, a unit is provided for each of a small number of points and a large number of points, but according to the present invention, an extension station can be used. Also, the input / output ratio can be changed freely.

(2) Since the additional interface is not used and identification is performed by the logical address, the additional interface can be omitted. (3) Since the extension station is also on the same communication path, the place of arrangement is not limited, and the extension station can be installed in an arbitrary empty space. Also, even if the controller has multiple systems, it can be easily connected (within communication specifications).

(4) In the fixed number of small points method, since multiple points are used,
Although it is necessary to install communication channels in multiple layers, in the present invention,
Since the number is one, wiring can be saved. (5) Unlike the conventional type with additional interface, no protocol converter is required. Further, in the invention according to claim 2, in addition to (6) the slave station is confirmed, there is no communication channel collision or erroneous input / output of I / O.

(7) Since the user is solicited for additional subscription while the I / O signal is being transmitted (during operation), the unit that is turned on later than the master station will be subject to operation after confirmation. Does not have to bother with the power sequence. (8) Since only one station is invited for additional subscription in one communication cycle, there is almost no delay in transmission to other operating units.

According to the third aspect of the present invention, the relay terminal is provided with means for detecting an abnormality in the output relay and the load circuit, and the detected abnormality is transmitted to the master station (relay master station) via the communication cable. (9) Answer back wiring is not required because the data is transmitted via the network. (10) Normally, the maximum number of terminals is specified in bus-type communication (due to impedance change), but in the answerback communication slave station system, the maximum number of terminals is reduced to half. However, the present invention does not reduce the number of terminals.

(11) There is an effect that the communication control section is not required twice and the cost and space are reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a device configuration of an I / O terminal system according to an embodiment of the present invention.

FIG. 2 is a partial block diagram showing a circuit configuration of the I / O terminal system of the embodiment.

FIG. 3 is a state transition diagram for explaining an operation process of a master station of the I / O terminal system of the same embodiment.

FIG. 4 is a block diagram showing a schematic configuration of a failure detection function I / O relay terminal of the I / O terminal system of the embodiment.

[Explanation of symbols]

 21 central control device 24 connection table 25 relay station 26 communication cable 28 master station 29 extension relay station 37 address setting switch 38 operation mode setting switch

Claims (3)

[Claims] 1. An I / O terminal system comprising a central controller, a relay station connected to the central controller, and a plurality of terminals connected to the relay station via the same transmission line, wherein a master relay is used as the relay station. In addition to the station, an optional repeatable relay station connected to the same transmission line as the terminal is provided, and the additional repeater station and the terminal are provided with address setting means and operation mode setting means, respectively. I / O terminal system. 2. The controller has a function of confirming the start-up of the additional relay station and each terminal and a function of soliciting additional subscribers in a time-division manner to non-subscribed stations. The I / O terminal system according to claim 1. 3. The relay terminal comprises means for detecting an abnormality of an output relay and a load circuit, and the detected abnormality is transmitted to a relay station via the transmission line. The I / O terminal system according to claim 1.