JPH0462638B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

This invention provides a plurality of terminal devices (also referred to as terminals),
The present invention relates to a data transmission system composed of a center device and a host computer, in which the host computer and the center device are provided with means for detecting changes in terminal data. Note that in the description of each figure below, the same reference numerals indicate the same or corresponding parts. In addition, logic High and Low are simply written as H and L.

[Prior art and its problems]

The prior art closest to the present application is Japanese Patent Application No. 59-244254 ``Data Transmission System'' filed by the present applicant. This type of technology and its problems will be explained below using FIGS. 5 to 9. FIG. 5 shows a system configuration diagram of this type of data transmission system. The center device 3 is connected to a large number of terminals 4 (4-1, to 4-n) via a signal path 5, and as shown by arrows a and b between the center device 3 and the terminals 4, Alternatively, data transmission is performed between terminals as shown by arrows c and d. Although the signal path with the terminal is connected in a loop in FIG. 5, it may also be connected in a multi-drop manner or branched. The function of the terminal is to transmit any connected digital or analog input signal 6 as serial data via the signal path 5. Also,
The terminal has a function of outputting the data received via the signal path 5 to the outside of the system as an output signal 7. Further, each terminal 4 is assigned a unique address and has a built-in address switch for setting. In the case of transmission between terminals (hereinafter referred to as N:N transmission method),
Although consecutive even and odd addresses are determined to mutually transmit data, this is because the transmission procedure has been determined in advance, and this can be considered as just one example. When an address is designated, the input signal of the terminal with the odd number address is transmitted, and the terminal with the even number address receives and outputs this signal. Data transmission is then performed between the terminals in such a way that the input signal of the even-addressed terminal is transmitted, and the odd-addressed terminal receives it. On the other hand, transmission between the center device and terminals (hereinafter 1:N
(referred to as a transmission method) is also performed as follows.
The center device is connected to the host computer 1 via a transmission line (RS232C cable or data bus) 2, and the host computer 1 sends terminal operation signals, etc. to the center device 3, and the center device 3 receives these signals. Sending output data to a terminal using a 1:N transmission system and outputting it to the outside from the terminal, and receiving input data from the terminal using 1:N transmission,
This received terminal data is transmitted to the host computer 1. In addition, since the center device 3 receives all the signals on the signal path 5, it can also monitor data in the N:N transmission method, and although the data transmission itself is carried out between terminals, the contents can be monitored. This makes it possible to transmit designated terminal data to the host computer 1 from among the N:N transmission data held by the center device 3 in response to a request from the host computer 1 . It is also possible for the center device 3 to detect changes in data transmitted using these N:N transmission methods and transmit them to the host computer 1. These 1:N and N:N transmission methods will be explained below. FIG. 6 shows an example of the transmission format of the 1:N transmission method transmitted by the center device 3. First, the center device 3 transmits block address data including the block address and data indicating that 1:N block communication should be started. Note that the block address here is an address that is assigned to a group (block) of a predetermined number of addresses of the terminals 4 (however, each terminal address within this group is ordered in advance). The block address data is received by all terminals, and the terminals with addresses belonging to this block address are set to a receiving state. Next, output data for 8 addresses is sequentially transmitted from the center device 3 to terminal addresses 0→1→2...→7, and these output data are received by the terminal that matches its own address and sent to the terminal 4. The output signal 7 is output from the output signal 7. The output data for each terminal address includes parity for preventing transmission errors, data for sum check, etc., and is configured so that when a data error occurs, the received data can be ignored. Conversely, when the center device 3 receives input data as the input signal 6 from the terminal 4, it specifies the block address to be communicated as shown in the transmission format example of FIG. 6. As a result, in the same way as above, the terminals 4 whose addresses belong to the block address in question are sorted in descending order of address 0→1→2...→
7 and send them in sequence. If the terminal at the previous address does not transmit, the terminal at the next address waits for a certain period of time, confirms that no data is transmitted, and then transmits the input data. This time is set to be shorter in ascending order of addresses, so that the terminal with the later address can always transmit when the previous address is not transmitting. With this configuration, even if the terminal being used skips over the middle of the address, failures due to missing numbers in the address will not occur. Also, data transmission between 4 terminals (N:N transmission)
In this case, the transmission format shown in FIG. 6 is used as is. In this case, the data transmitted by the terminal is simply received by a terminal that has a specific address relationship with the transmitting terminal, and the center device 3 monitors these transmitted data and transmits the data to the center device. It is designed to be set in RAM. The transmission format shown in FIG. 6 shows the case of block communication, but communication performed for each individual address is also used. Figure 7 shows the terminal data owned by the center device.
FIG. 3 is an explanatory diagram of arrangement columns in RAM. In this example, the terminal address is, assuming the maximum number of terminals is 64 terminals,
Addresses 1, 2, . . . , 64 are provided, and the input data of these terminals is sequentially stored in the RAM by the CPU in the center device. 7th
In the example shown in the figure, the input data length of the terminal is 32 bits, so Di ₀ , Di ₁ , Di ₂ , and Di ₃ each have 8 bits, meaning a total of 32 bits of data. Also, the status of the terminal, such as a state in which data transmission is not possible between the center device and the terminal, or a state in which the analog input amount of the terminal is outside the specified range (for example, a disconnection in the signal circuit)
If the terminal is in an abnormal state, such as when the terminal is in an abnormal state, failure data is sent from the terminal and is similarly set as status data by the CPU. Regardless of whether the center device uses the 1:N transmission method or the N:N transmission method, all transmitted data is received by the center device.
The input data of all terminals is stored in the RAM of the center device.
held within. On the other hand, since terminal data is received by the center device each time it communicates with a terminal, the center device compares it with the previously received terminal data (Di data) that it already owns in Figure 7 and determines whether there is any change. After checking "None", update the corresponding Di data in FIG.
If the input data has changed, check whether the terminal in question is registered as a terminal that should monitor input data changes (also referred to as a changing terminal), as described below, and if it is registered, Furthermore, the eighth
Change data having the configuration shown in the figure is sequentially set in the RAM (also referred to as change memory) in the center device. In this case, if the terminal data input by the center device is a digital signal, multiple verification (for example, data is established when the data matches three times in a row), or if it is an analog signal, there is a restriction on the width of change. By providing functions such as processing and averaging to prevent terminal data from being received in an incorrect form even if there is a simple noise signal, it is possible to compare the data received by the center equipment as is. It is. In each storage area of change data in FIG. 8, in addition to the address of the terminal that the center device has determined has actually caused a data change (one of the change terminals) and the input data Di ₀ to Di ₃ of the terminal, , the failure data sent from that terminal is stored in the status data location. Furthermore, communication abnormalities for each terminal address determined by the center device are also set as status data. FIG. 9a is an explanatory diagram of how to use these change data RAM (change memory). The change data is stored in the change memory in the order of occurrence in the order in which any change is detected. However, the changed data of all the terminals is not stored, but only the changed terminals are stored. In this case the ninth
The change data is stored in the data area next to the value of the change data set counter (CNT) in FIG. b, and the value of CNT is set to +1. The change data area in FIG. 9a is change data 1 to n.
This number indicates change data CNT, and if CNT reaches n, it is stored as change data 1 again and is used repeatedly. If there is unsent data in the change data, the change data is sequentially sent from the center device to the host computer, but the CNT value of the sent change data is stored in the change data transmission CNT shown in Figure 9b and is not sent. The value of this CNT is incremented by 1 each time. Note that a new problem arises when the registration of a changed terminal as described above is cancelled. This is a case where there is unsent change data in the host computer, and among the unsent change data there is change data of a terminal whose registration as a change terminal has been canceled. This means that after a terminal with a certain address is canceled as a changed terminal, the changed terminal data is sent from the center device. Indeed, if it is just a single cancellation,
It seems easy for the host computer to ignore this change data. However, under certain conditions, the registration as a change terminal is canceled,
If the following condition occurs again and a subsequent change in terminal data is requested using the same terminal as a change terminal, if the previous unsent data is sent after re-registration, the host computer will update the previous data. Since it is not possible to determine whether the data is a change to the registration or data that has changed after being re-registered, the host computer will make a misjudgment. For this reason, a sent flag F is provided in the changed data in FIG. 8, and if there is data of a terminal whose registration has been canceled as a changed terminal among the unsent terminal data, the sent flag F is set. set,
Transmission of the change data to the host computer is prohibited. This sent flag F is used to prevent past unsent changed data from being sent even if the host computer requests the current terminal data that was registered as a changed terminal before the changed data. Additionally, if there is change data for the same terminal address, the transmitted flag F is set and subsequent transmissions are prohibited. These changing terminals include N between terminals:
It can also be applied to terminals of N transmission systems. In other words, the terminal data that is being monitored by the center device can also be constantly monitored, and the terminal data can be transmitted from the center device to the host computer, so the host computer can also freely monitor the N:N transmitted data, and detect abnormalities, for example. It is also possible to take appropriate measures when such a situation occurs. In addition, the change data RAM shown in Figure 8 stores changes in terminal data and occurrences of failures in chronological order, so it can be used as important data when examining system behavior in the event of an abnormal condition. can do. Therefore, when the center device receives a change data dump instruction (command) from the host computer, it sends the unsent change data to the host computer in the order in which it was sent in the past, so that the host computer can identify the cause of the abnormality. It is possible to investigate. By configuring as described above, terminal data can be monitored every time there is communication within the center device, and can be transmitted to the host computer preferentially compared to other communication data. In such a transmission system, e.g.
If the emergency switch signal is activated at an FA factory, etc.,
If the signal level can be transmitted preferentially compared to other signals, there is no need for the host computer to receive the signal level of the emergency switch via the center device every time, so the processing function of the host computer can be significantly reduced. However, in this transmission system, there is a problem that the host computer 1 becomes too busy as described below, and as a result, the transmission of necessary data from the host computer to the change terminal is delayed. (1) Changes in terminal input data are captured in the form of a collective input data, but there are many cases of input data that do not pose a problem in themselves, but are simply changes in bit signals such as specific limit switches. It is desirable to detect a change in an arbitrary bit signal in the terminal input signal 6, so that transmission at a particularly high speed is desired only when a signal occurs. (2) Analog quantities such as rotation speed, voltage, current,
When temperature, etc. is transmitted as a terminal input signal, the host computer detects whether the terminal input signal has reached a specific upper limit or lower limit, or has changed by a predetermined hysteresis, rather than the continuously changing terminal input signal. It is important to detect whether or not this has occurred. (3) When detecting changes, there are cases where it is desired to simply detect a change, rather than requesting data transmission every time an input signal changes. In this case, the host computer first registers the terminal in question as a changed terminal, and upon receiving the changed data of that terminal, makes a logical judgment as to what has changed in the changed data, and as a result, if the changed data If it becomes unnecessary, communication must be performed to cancel the registration as a change terminal, which complicates the program on the host computer side. (4) When the host computer receives changed data as described above, makes a logical judgment, and then cancels the registration, new changed data will be generated during the processing time.

[Purpose of the invention]

The present invention eliminates the above-mentioned problems, further divides the specification of the change conditions of the terminal change data that the host computer wants to receive, and makes it possible to specify to detect only when a specific situation changes. Furthermore, it is an object of the present invention to provide a data transmission system in which the effective period of change detection on the center device side can also be specified.

[Key points of the invention]

The main points of the present invention include a center device that controls data transmission and has the function of receiving data from connected terminals, a plurality of terminals connected from the center device via a transmission path, and the center device and a bus. In a data transmission system consisting of host computers connected via a data transmission path, the host computer sends the center device the address data of the terminal whose changes in terminal data are to be detected and the information for the terminal. Command data or (and) to the effect that one or both of changes from H to L or from L to H should be detected for predetermined one or more bit data in input digital data.
Command data to the effect that one or both of a predetermined upper limit value or a lower limit value for input analog data to the terminal and a change to a value that is a predetermined hysteresis value away from the upper or lower limit value should be detected ( (detection specification code, etc.) and the change detection described above.
The center device has means for transmitting data specifying whether the data is to be changed once or repeatedly (one-time change code, permanent change code, etc.), and the center device transmits data from the host computer to the terminal data among the terminal data received by the center device. The device has a means (such as a CPU) for detecting the change in the data of the terminal specified by the address data, and a means (such as the CPU) for transmitting the terminal data to the host computer when the change is detected. That's what I did.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on FIGS. 1 to 3. FIG. 1 is a diagram showing the structure of detection designation command data sent from a host computer to a center device as an embodiment of the present invention, FIG. 2 is a diagram showing the types and contents of the detection designation command, and FIG. 3 4 is a diagram illustrating setting values for detecting changes in terminal analog data, and FIG. 4 is a diagram illustrating a communication sequence between the center device and the host computer.
FIG. 4 is a diagram showing a conventional communication sequence corresponding to FIG. 1. In the present invention, the transmission data transmitted from the host computer 1 to the center device 3 includes the above-mentioned terminal operation signal, that is, the transmission of output data to the terminal 4 from the host computer to the center device, or the input data of the terminal 4. In addition to the signal to be sent from the center device to the host computer, detection designation command data 50 as shown in Figure 1 is newly added, and based on this command data, the center device checks the contents of the terminal change data. , Only when a predetermined change occurs, the terminal data at that time is transmitted to the host computer. In FIG. 1, 51 is data indicating that this transmission data is detection designation command data, 52
5 is a registration/deletion command, and data indicating whether this transmission data 50 is for newly registering that terminal change data should be checked or for deleting an already registered check command;
3 is the detection specification code as described in Fig. 2, 54
(54-1, ~, 54-n) is data for each terminal, 54a (54a1 to 54an) is the address of the terminal to be monitored for changes in input data, and 54b (54b
1 to 54bn) are setting data for the corresponding terminals, which will be described later. Next, in FIG. 2, numbers 1 to 27 are numbers indicating the type of detection designation code 53, 61 is the content of the code 53, 53 (53a, 53b) is the detection designation code, and 53a is the terminal input in question. Repeatedly from the center device 3 to the host computer 1 every time a data change occurs.
A designation code (also referred to as a permanent change code) 53b indicates that the terminal data should be sent to the center device 3 when a change in the terminal input data occurs once.
This is a designation code (also referred to as a one-time change code) indicating that after the terminal data has been sent to the host computer, it is not necessary to send the terminal data to the host computer thereafter. Detection designation code 53 (value
10H to 12H or 90H to 92H) respectively change from H to L when a predetermined bit (described later) in the terminal input data changes from H to L or from L to H, or from L to H. It means that the terminal data should be sent to the host computer when there is a change in the terminal data, and in this case, the terminal address 54a in the command data 50 in FIG. In the setting data 54b corresponding to the terminal, data indicating the bit position to be monitored in the input signal 6 at the terminal is stored. Next, the meanings of the detection designation codes 53 (values 20H to 27H or A0H to A7H) in Nos. 4 to 11 of FIG. 2 will be explained with reference to FIG. 3. In FIG. 3, reference numeral 70 indicates one piece of terminal analog data (for example, temperature) that is subject to change monitoring, and time is plotted on the horizontal axis, and an example of the temporal transition of the analog data 70 is shown. t1 is the point in time when the analog data 70 exceeds a preset upper limit value (described later) 71, and t2 is the point in time when the analog data 70 is lowered based on the terminal control signal (for example, ON/OFF command, etc.) of the host computer 1 at the time t1. Entering the process, the hysteresis value 72 is preset from the upper limit value 71.
It shows the point in time when the value falls below the return value 73, which has fallen by (described later). Now, each of the detection designation codes 53 (Nos. 4 to 11) corresponds to the upper limit value 71 (1 point) to which the terminal analog data 70 subject to change monitoring corresponds, and this value is included in the setting data 54b of FIG. ) is exceeded (set for each address 54a) at the time t1,
and a time point t2 when the value falls below this upper limit value 71 by the corresponding hysteresis value 72 (this value is given for each detection designation code in Fig. 2, and a total of 8 levels of values can be selected). This is a code that indicates that the input data of the terminal should be transmitted from the center device 3 to the host computer 1. Detection designation code 5 in Figure 2 Nos. 12 to 19
3 (value 30H to 37H or B0H to B7H) is No. 4 to 1
Similarly to the same designation code 53 in Figure 1, the lower limit value (1 point, this value corresponds to the setting data 54b in Figure 1) corresponds to the terminal analog data subject to change detection.
is set for each address 54a of the target terminal. ), and then a corresponding hysteresis value (this value is given for each detection designation code value in FIG. 2, and a total of 8 levels of values can be selected from this lower limit value). ) is a code that indicates that the terminal data should be sent to the host computer at the time the terminal data exceeds the limit. In addition, the detection designation codes 53 (values 40H to 47H or C0H to C7H) in Nos. 20 to 27 in Figure 2 are the upper and lower limit values (total of 2 points, respectively) corresponding to the terminal analog data that is subject to change detection. The two values are set by adding one word of data corresponding to the setting data 54b for each terminal data 54 in FIG. 1. At the point when the value changes by the corresponding hysteresis value (this value is given for each detection designation code in Figure 2 as above, and a total of 8 levels of values can be selected). This is a code indicating that the terminal data should be sent to the host computer. By receiving the detection designation command data 50 including the detection designation code 53 as described above from the host computer 1, the center device 3 repeats 1:N communication with the terminal 4 and receives the terminal input transmitted from the terminal. The data is checked to determine whether there is a change given by the designation code 53, and the terminal input data is immediately transmitted to the host computer 1 at the time when the change occurs. The host computer 1 thereby transmits control data (ON, OFF commands, etc.) to be given to the corresponding terminal to the center device 3, and the center device 3 then transmits the control data to the corresponding terminal 4 in the next 1:N communication. An example of such a communication sequence between the host computer 1 and the center device 3 is shown in FIG. 4. Data input on the center device side in FIG. 1 means reception of changed terminal input data, and data judgment means the data judgment given by the detection designation code 53. In the present invention, data is transferred to the host computer 1 only when it is determined in this data judgment that there has been a change corresponding to the designation code 53, and the host computer 1 thereby performs the necessary control processing and transfers the control data. It is sent to the center device 3. The center device 3 outputs this control data to the terminal side. In this way, since the host computer communicates only lean data with the center device, the burden of terminal control processing on the host computer can be reduced and the control response speed can be increased. On the other hand, in the conventional method shown in FIG. 4, each time the center device 3 receives terminal change data, it is sent to the host computer 1, and the host computer 1 determines whether there is a necessary change in the received data each time. Therefore, while this determination process is busy, the necessary control response operation becomes slow. Note that A in the figure indicates the time during which the host computer 1 can execute processes other than the terminal control process, and it can be seen that the time A can be made larger in FIG.

【Effect of the invention】

As is clear from the above description, according to the present invention, the host computer sends a command including necessary change condition setting data for terminal data to the center device in advance, and the center device The process of determining whether or not there is a predetermined change in the value or analog value that is meant by this setting data is performed by the center device, which has more time than the host computer, and only when this change occurs, input from the terminal is performed. Since data is received from the center device and the corresponding control data is given to the terminal via the center device, the burden of terminal control processing on the host computer and its program execution time are reduced, and the program execution time for programs other than terminal control is reduced. In addition to increasing the processing execution time and speeding up the processing time, terminal input data is immediately compared in the center device and the results are transmitted to the host computer, allowing for more detailed terminal input. Data can be checked. In addition, since changes in terminal input data can be transmitted only once, data processing on the host computer can be simplified by eliminating unnecessary data transmission to the host computer. There is.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of detection designation command data as an embodiment of the present invention, FIG. 2 is a diagram showing the types and contents of the detection designation command, and FIG. 3 is also a diagram for detecting changes in terminal analog data. FIG. 4 is a diagram explaining the setting values of , FIG. 4 is a diagram showing the communication sequence between the host computer and the center device, FIG. FIG. 6 is an explanatory diagram of an example of a transmission format; FIG. 7 is an explanatory diagram of an example of arrangement of terminal data owned by a center device in RAM; FIG. This figure is a configuration diagram of an example of a change data RAM owned by the center device, and FIG. 9 is an explanatory diagram of an example of how to use the change data RAM. 1: Host computer, 2: Transmission path, 3: Center device, 4 (4-1, ~, 4-n): Terminal, 5: Signal path, 6: Input signal, 7: Output signal, 50: Detection specification command Data, 53: Detection specification code, 53
a: Permanently changed code, 53b: Once changed code,
54 (54-1, ~, 54-n): terminal data,
54a (54a1 to 54an): Terminal address, 5
4b (54b1 to 54bn): Setting data, 71:
Upper limit value, 72: Hysteresis value.

Claims (1)

[Scope of Claims] 1. A center device that controls data transmission and has the function of receiving data from connected terminals, a plurality of terminals connected from the center device via a transmission path, and a center device and data In a data transmission system consisting of host computers connected via a transmission path, the host computer sends the center device the address data of the terminal whose terminal data changes should be detected and the input data to the terminal. Command data or (and) to the effect that one or both of changes from H to L or from L to H should be detected for predetermined one or more bit data in digital data.
A predetermined upper limit value or a predetermined lower limit value or both of the input analog data to the terminal, and command data to the effect that a change to a value that is a predetermined hysteresis value away from the upper or lower limit value should be detected. , and means for transmitting data specifying whether the change detection is to be performed only once or repeatedly; 1. A data transmission system comprising: means for detecting the change in data of a designated terminal; and means for transmitting the terminal data to a host computer when detecting the change.