JPH0345055A - Notice method for state of connected device in data transmission system - Google Patents

Abstract

PURPOSE:To improve the data processing efficiency by adding a change notice bit at a sender side when there is a change in the device state of each device and generating a state change interrupt signal at a receiver side only when the change notice bit is detected and executing the retrieval processing to each device state at that time only so as to revise the content of a sub device state table. CONSTITUTION:When a change is caused in the device state of each device 4 connected to a data transmitter 1, the relevant device state of a master device state table 5 is revised and a change notice bit is set to a storage section. When a prescribed period elapses, each device state of the master device state table 5 after the revision and a data and a change notice bit are sent to a data transmitter 2 as data information. A data processing unit 2 receiving the data information has a change notice bit in the data information, then a state change interrupt signal is outputted from an interrupt generating circuit 12 and the device state of each device stored in its own sub device state table 10 is revised into a new device state in response to the state change interrupt signal. Thus, the data processing efficiency is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a data transmission system that exchanges data between data transmission devices at a constant cycle, and particularly relates to a data transmission system that transmits and receives data between data transmission devices at regular intervals. The present invention relates to a method for notifying the status of connected devices in a data transmission system in which the status of each connected device is grasped by another data transmission device.

(Prior Art) A data transmission system that exchanges data between a pair of data transmission devices is, for example, as shown in FIG. It has a connected configuration.

Each data transmission device 1, 2 is generally composed of a control device such as a computer, and has path lines la, 2, respectively.
a has a CPU (central processing unit) 1b;

2b1 memory lc, 2c, transmission interface 1, d,
This is a configuration in which 2d are connected.

Further, for example, a large number of devices 4 are connected to one data transmission device 1 via an l10 (input/output) boat 1e. Also, the period T of data exchange performed with the other data transmission device 2. A timer 1f is provided to measure the time.

Further, the other data transmission device 2 is provided with a CRT display section 2g for displaying data received from one data transmission device 1.

In such a data transmission system, the device status of each device 4 connected to one data transmission device 1 is transmitted to the other data transmission device 2 in addition to the one data transmission device 1 to which each device 4 is connected. Sometimes it is necessary to understand.

For example, the current status of each device 4 is displayed on the CRT display section 2g.

As a general method for notifying (transmitting) the device status of the connected device 4 to the other data transmission device 2, the first
As shown in FIG. 0, the memory l of one data transmission device 1
A main equipment status table 5 is provided in c. In this main equipment status table 5, the boat N (L P 1.P 2.P 3..
・Equipment status data D for each PN 1. D2. ...
, memorize the DN. And CPU1b is always I10
Equipment status data Dl of each boat PL-PN of boat 1e
-DN is monitored, and if there is a change in each of the device status data D1 to DN, the corresponding device status data in the main device status table 5 is changed to new device status data.

Then, the constant period T starts from the timer 1f. When each time interrupt occurs, the data memory 6 provided in the memory lc is
The data to be transmitted stored in the main device status table 5 and each device status data Di-DN in the main device status table 5 are transmitted as data information to the other data transmission device 2 via the transmission interface 1d and the data transmission path 3.

The other data transmission device 2 receives data information from one data transmission device 1 via the transmission interface 2d.
performs normal data processing on the data contained in the data information. Furthermore, each device state data D1 to D'N included in the received data information and each device state data Dl-DN set in the previous cycle in the sub-device state table provided in the own memory 2C. If there is any missing equipment status data, the corresponding equipment status data in the sub equipment status table is updated to the new equipment status data received this time.

Therefore, the device status of each device 4 connected to one data transmission device 1 can always be accurately grasped by the other data transmission device 2.

However, even in the above-described method of notifying the device status of each device 4 to the other data transmission device 2, the following problems still exist.

That is, one data transmission device 1 transmits each device state data D1 to D1 in the main device state table 5 at regular intervals, regardless of whether the device state of each device 4 has changed or not.
The DN is sent to the other data transmission device 2 along with normal data. Therefore, the other data transmission device 2 transmits each device data D1 to DN of the received data information and the sub-device status table at regular intervals, regardless of whether the device status of each device 4 has changed or not. It is necessary to compare each of the device status data D1 to DN in the list to find out whether different device status data exists.

Since this search operation requires a large number of processing steps, there is a problem that the processing load on the other data transmission device 2 increases and the processing efficiency of regular data processing decreases. In particular, in a data transmission system in which the device status of each device 4 does not change very frequently, there is a high probability that the other data transmission device 2 will not have different device status data that has been searched for, resulting in an unnecessary number of unnecessary search operations. We will also do
There is a concern that the data processing efficiency described above will be significantly reduced.

(Problem to be Solved by the Invention) As described above, according to the conventional method for notifying the connected device status of a data transmission system, the search processing work that ends up being wasted in the other data transmission device that receives the device status data can be avoided. This increases the problem of lowering the original data processing efficiency.

The present invention was made in view of these circumstances, and
When a change occurs in the device status of each device, a change notification bit is added on the sending side.By doing so, the receiving side only needs to perform search processing for each device status when the change notification bit is detected, which eliminates wasteful search work. It is an object of the present invention to provide a method for notifying the status of connected equipment in a data transmission system, which can eliminate problems and greatly improve the original data processing efficiency.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the method for notifying the status of connected devices of the present invention provides a method for notifying a connected device status via a data transmission path with one data transmission device to which a plurality of devices are connected. A data transmission system that sends and receives data at regular intervals to and from another data transmission device that is connected to one data transmission device, and that at least the other data transmission device grasps the device status of each device connected to one data transmission device. When one of the data transmission devices monitors each device and detects a change in device status, it updates the corresponding device status in the main device status table that stores the device status of each device, and sets a change notification bit in the storage unit. and transmits data information consisting of the data, each device status of the main device status table, and a change notification bit to the other data transmission device at regular intervals, and the other data transmission device receives the data from one data transmission device. When information is received and a change notification bit is detected in the received data information, the interrupt generation circuit generates a state change interrupt signal, and the self The device status of each device stored in the sub-device status table set in the storage section of is updated with each device status included in the received data information.

(Operation) According to the method for notifying the connected device status in the data transmission system configured as described above, when a change occurs in the device status of each device connected to one data transmission device, the corresponding device in the main device status table The state is updated and a change notification bit is set in the storage. Then, after a certain period has elapsed, each device status, data, and change notification bit of the updated main device status table are transmitted as data information to the other data transmission device.

In the other data processing device that has received the data information, since there is a change notification bit in the data information, a state change interrupt signal is output from the interrupt generation circuit, and the state change interrupt signal is responded to. The device status of each device stored in its own sub-device status table is updated to the new device status.

Therefore, if the device status of each device does not change, the change notification bit will not be set, so the other data transmission device needs to search and update each device status stored in its own sub-device status table. do not have.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a data transmission system employing the method of notifying the status of connected devices according to the embodiment. The same parts as in FIG. 9 are given the same reference numerals.

Therefore, the explanation of the overlapping parts will be omitted.

For example, N devices 475 are connected to one data transmission device 1 via an I10 boat 1e, and a CPU 1b
indicates the device status of each device 4 to each port PI of I10 port 1e.
, P2. ... can be monitored via the PN. Note that the connected devices 4 include, in addition to normal peripheral devices such as printing devices, display devices, and input/output devices, other computers, programmable controllers, programmable displays, and the like.

As shown in FIG. 2, in the memory 1c formed of a RAM or the like, the port number, PL, P2 . P3. -, equipment status data D for each PN 1. D2. ..., a main crisis state table 5 storing DNs is provided. Furthermore, within the memory 2c, there is a data memory 6 that stores normal data to be transmitted to the other data transmission device 2, and a change notification bit B that indicates that a change has occurred in the device status data D1 to DN of each device 4.
A bit memory 7 for storing data information, a transmission buffer 8 for temporarily storing data information to be transmitted to the other data transmission device 2, and the like are formed.

In addition, as shown in FIG. 3, the memory 2c of the other data transmission device 2 includes a reception buffer 9 that temporarily stores data information received from the one data transmission device 1, and is connected to the one data transmission device 1. Equipment status data D of each equipment 4 that has been updated 1. D2. ..., a sub-equipment status table 10 having the same configuration as the main equipment status table 5 that stores DNs.
A data memory 11 and the like for storing normal data are formed.

Furthermore, an interrupt generation circuit 12 is provided within the data transmission device 2. This interrupt generation circuit 12 detects the change notification bit B in the reception buffer 9 and applies a state change interrupt signal to the CPU 2b.

In a data transmission system having such a configuration, the CPU 1b of one of the data transmission devices 1 to which each device 4 is connected executes the interrupt process shown in FIG. . That is, each device state data of each device 4 input to each port P1 to PN of the I10 port 1e is read. Then, each device status data D stored in the main device status table 5 of the memory 1c
Compare with l-DN. If there is even one item of equipment status data that does not match, the corresponding equipment status data in the main equipment status table 5 is rewritten with the new equipment status data read this time. Then, the value of the change notification bit B in the bit memory 7 is inverted.

Note that if all the device status data match, the time interrupt processing for each minute time Δτ is completed without doing anything.

Furthermore, a constant period T is set from the timer 1f to be longer than the minute time ΔT. If the interrupt signal is manually generated every time, the 5th
Execute the interrupt processing shown in the figure. That is, each device status data D1 to DN in the main device status table 5, normal data for transmission in the data memory 6, and change notification bit B in the bit memory 7 are set in the transmission buffer 8 as data information.

Then, the data information in the transmission buffer 8 is transmitted to the other data transmission device 2 via the transmission interface 1d and the data transmission path 3.

Next, the CPU 2b of the other data transmission device 2 executes the main routine shown in FIG. When the main routine starts, it is checked whether data information is received from one of the data transmission devices 1 in the reception buffer 9, and if it is received, normal data from among the data information in the reception buffer 9 is sent to the reception buffer 9. Store it in the data memory 11. Then, predetermined data processing is performed on the data.

Further, the interrupt generation circuit 12 executes the processing shown in FIG. That is, when data information is received in the reception buffer 9, the state of the change notification bit B included in the data information is checked. If the value of the previous change notification bit B is different from the value of the current change notification bit B, there is a device 4 whose device status has changed in the current cycle, so the CPU 2b
Sends a state change interrupt signal to the interrupt terminal of

Note that if the change notification bit B does not change, nothing is done.

Thus, the CPU 2. to which the state change interrupt signal is applied from the interrupt generation circuit 12. b executes the state change interrupt processing shown in FIG. That is, each device state data Di to DN of the data information received in the reception buffer 9 is read. Next, it is compared with each device status data DI-DN in the sub-equipment status table 10. Then, it searches for equipment status data that does not match the equipment status data read from the reception buffer 9, and updates that equipment status data to new equipment status data. Therefore, each device data Dl-DN of the sub-device status table 10
is each device status data DI-DN of the main device status table 5
matches.

According to the method for notifying the state of connected devices in a data transmission system configured as described above, when the crisis state of one or more devices 4 among the plurality of devices 4 connected to one data transmission device 1 changes, the above-mentioned If the minute time ΔT is ignored, the device state data of the corresponding device in the main device state table 5 is rewritten to new device state data after the change at the time of change.

At the same time, change notification bit B of bit memory 7 is set to 1. And a constant period T. After , each device state data and change notification bit B of the main device state table 5 are transmitted to the other data transmission device 2 together with normal data. On the data transmission device 2 side, the inverted change notification bit B is detected by the interrupt generation circuit 12 and a state change interrupt signal is generated. Then, each received device state data and each device state data in the sub device state table 10 are searched, and each device state data that has changed in the sub device state table 10 is updated to new device state data.

Note that the period T at the time when data information is transmitted from one data transmission device 1 to the other data transmission device 2. If the device status does not change within that time, change notification bit B will not change. Therefore, in this case, the interrupt generation circuit 12 on the other data transmission device 2 side that has received the data information does not generate a state change interrupt signal. Therefore, the CPU 2b does not search the received device status data or the sub-device status table 10 for device status data that does not match.

That is, the data transmission device 2 on the receiving side updates the sub-device status table 10 by performing the above-mentioned search process only when the device status of each device 4 connected to one data transmission device 1 changes. good.

Therefore, unlike the conventional method, search processing is not performed at regular intervals regardless of whether there is a change in the device status, so it is possible to omit search processing that ends up being wasted, and the original data processing efficiency is greatly improved. can.

[Effects of the Invention] As explained above, according to the connected device status notification method of the present invention, when a change occurs in the device status of each device, the transmitting side adds a change notification bit, and the receiving side sends a change notification. A state change interrupt signal is generated only when a bit is detected, and only when the interrupt signal is generated, search processing for each device state is executed to update the contents of the sub-device state table.

Therefore, unnecessary search work can be eliminated, and the original data processing efficiency of the data transmission system can be greatly improved.

[Brief explanation of drawings]

1 to 8 show a data transfer system that employs a method for notifying the status of connected devices according to an embodiment of the present invention. FIG. 1 is a block diagram showing the entire system, and FIGS. The figures show the contents of memory, Figures 4 to 8.
The figure is a flowchart showing the operation, and FIG. 9 is a block diagram showing a data transmission system employing the conventional notification method.
FIG. 0 is a diagram showing the contents stored in the memory in the conventional system. 1.2... Data transmission device, 3... Data transmission line,
4...Device, 5...Main device status table, 7...
Bit memory, 8...Transmission buffer, 9...Reception buffer, O...Sub-equipment status table, 2...Interrupt generation circuit.

Claims (1)

[Scope of Claims] Data is exchanged at a constant cycle between one data transmission device to which a plurality of devices are connected and the other data transmission device connected via a data transmission path, and In a data transmission system in which at least the other data transmission device grasps the device status of each device connected to the data transmission device, the one data transmission device monitors each of the devices and detects a change in the device status. The corresponding device status in the main device status table that stores the device status of the device is updated, and the change notification bit is set in the storage unit, and the data, each device status in the main device status table, and the change notification are updated at the fixed period. transmitting data information consisting of bits to the other data transmission device, the other data transmission device receiving the data information from the one data transmission device, and including the change notification bit in the received data information. When detected, the interrupt generation circuit generates a state change interrupt signal, and in response to the state change interrupt signal from the interrupt generation circuit, the above-mentioned information is stored in the sub-equipment state table set in its own storage unit. A method for notifying a connected device status in a data transmission system, characterized in that the device status of each device is updated with each device status included in the received data information.