JP2004318710A - I/o transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a master device to set a transmission monitoring time from a maintenance monitoring device. <P>SOLUTION: The system comprises a central station 100 provided with a maintenance monitoring device 10, a power supply device 20, a programmable logic controller 30 and a master device 40, and at least one slave devices 60 connected to the master device via a transmission path. In the system, the master device performs the I/O transmission with the slave devices for a certain period in order for the programmable controller to exchange I/O data with the slave devices. In the case where the master device 40 starts the online I/O transmission with the programmable controller 30, before such starting, the master device 40 performs the offline transmission, measures the time from data sending to response reception and reports the measurement result to the maintenance monitoring device 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention comprises a maintenance monitoring device, a central station having a power supply device, a programmable controller and a master device, and one or more slave devices connected to the master device by a transmission line, wherein the master device is a slave device. In the I / O transmission system in which the programmable controller exchanges I / O data with the slave device by performing the I / O transmission at every transmission cycle between the I / O transmission and the transmission monitoring time from the maintenance monitoring device to the I / O transmission, The present invention relates to a technique for setting the master device.
[0002]
[Prior art]
FIG. 8 shows a configuration diagram of a conventional I / O transmission system. As shown in FIG. 8, a conventional I / O transmission system includes a central station 100 including a master device 40, a power supply device 20, and a programmable controller 30, one or more slave devices 60, and a transmission line 40 connecting these devices. , Is composed of. Then, in order for the programmable controller 30 to exchange I / O data with the slave device 60, the master device 40 performs I / O transmission with the slave device 60 every transmission cycle. Further, the maintenance monitoring device 10 is connected to the central office 100 and sets the transmission cycle of the master device 40. When receiving the transmission cycle set by the maintenance monitoring device 10, the master device 40 starts transmission / reception with the slave device 60 according to the transmission cycle and exchanges I / O data (for example, Patent Document 1).
[0003]
[Patent Document 1] Japanese Patent Application Laid-Open No. 05-028024
FIG. 9 is a time chart at the time of normal transmission from the master device to each slave device. This time chart shows a state of normal I / O transmission between the master device and two slave devices.
[0005]
[Problems to be solved by the invention]
However, as shown in FIG. 10, when the slave device connected to the transmission path stops responding for some reason, the master device reports an abnormality of the slave device due to the timeout of the transmission monitoring timer. As the value set in the transmission monitoring timer, a relatively large fixed value in seconds is provided in the master device. As described above, in the conventional method, a large value is set for the transmission monitoring timer so as not to be affected by the responsiveness of the slave device connected to the transmission path, and it takes a long time until an abnormality is detected. Had the problem of having a significant effect.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem, and measures the time from transmission of data to reception of a response by the master device by performing offline transmission before the master device starts normal I / O transmission. The measurement result and a transmission monitoring time calculated based on the measurement result are reported to the maintenance monitoring device so that the master device can set the transmission monitoring time from the maintenance monitoring device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a maintenance and monitoring device, a central station including a power supply device, a programmable controller and a master device, and one or more slaves connected to the master device by a transmission line. An I / O transmission system in which the master device performs I / O transmission with the slave device at regular intervals and the programmable controller exchanges I / O data with the slave device. Before the master device starts online I / O transmission with the programmable controller, the master device performs offline transmission before the master device measures the time from data transmission to response reception. The measurement result is reported to the maintenance monitoring device.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific examples of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of the I / O transmission system of the present invention. The same parts as those shown in FIG. 8 are denoted by the same reference numerals, and detailed description will be omitted.
In the figure, a feature different from FIG. 7 is a master device 40. As shown in the figure, the master device 40 starts transmission with the slave device 60 if the switch is set to perform offline transmission. At this time, the master device 40 measures the time from data transmission to response reception, and reports it to the maintenance monitoring device 10 via the programmable controller 30. The master device 40 stops transmission when the number of data transmissions reaches a certain predetermined number, for example, 100, calculates a transmission monitoring time based on the measured response time, and reports it to the maintenance monitoring device 10. The operator checks the transmission monitoring time reported to the maintenance monitoring device 10, changes the transmission monitoring time as necessary, and sets it in the master device 40. The master device 40 exchanges I / O data with the programmable controller 30 and reports a transmission abnormality. If the switch is set to perform online I / O transmission, the transmission cycle and the transmission monitoring time set by the maintenance monitoring device 10 are received via the programmable controller 30 and the I / O transmission is started.
[0009]
FIG. 2 is a block diagram of the master device 40 shown in FIG. In the figure, the master device 40 comprises a system control means 300 and a transmission control means 310.
The system control means 300 is connected to a switch / LED 301 connected to a switch / LED 301 for selecting whether to perform online I / O transmission for performing I / O data exchange and transmission abnormality report with the programmable controller or offline transmission. I / O data is exchanged between the I / O port circuit 302 and the programmable controller 30, and a transmission cycle and transmission required for starting I / O transmission with the slave device 60 between the I / O port and the maintenance monitoring device 10. A shared memory area 306 for exchanging setting data such as monitoring time from the programmable controller 30 via the system bus 303; a system work area 304 for storing parameters related to offline transmission; And a system control unit 305 that manages
The transmission control means 310 includes a transmission work area 311 for exchanging data with the slave device, and a transmission interface unit 312 connected to the transmission port 313 and performing transmission with the slave device.
[0010]
FIG. 3 is a data configuration diagram of parameters related to offline transmission provided in the master device. The transmission monitoring time area is a set value for reporting, based on the time from data transmission to receiving a response when the master device 40 performs offline transmission, to the maintenance monitoring device 10 via the programmable controller 30. Is an area for storing. The transmission monitoring time area is also an area for storing a set value that the master device 40 receives from the maintenance monitoring device 10 via the programmable controller 30. The ST number area is an area for storing a number corresponding to the slave device 60 connected to the transmission path 50, and the ST number takes a unique number on one transmission path. The current value area is an area in which the master device 40 stores a time from the data transmission to the reception of the response and the immediately preceding time. The minimum value area is an area for storing the minimum time of the time from when the master device 40 transmits data to when it receives a response. The maximum value area is an area for storing the maximum time of the time from when the master device 40 transmits data to when it receives a response. The average value area is an area for storing a value obtained by dividing the total response time from when the master device 40 transmits the data to when the response is received by the number of data receptions. The cumulative response time area is an area for storing a time obtained by adding the time from when the master device 40 transmits data to when a response is received. The data reception number area is an area in which a value counted by one every time the master device 40 receives data from the slave device 60 is stored. The data transmission number area is an area in which a value counted by one every time the master device 40 transmits data to the slave device 60 is stored. The transmission / reception execution flag area is an area that is turned on (1) when the master device 40 transmits data to the slave device 60 and turned off (0) when data is received from the slave device 60.
[0011]
FIG. 4 is a time chart of transmission between the master device and each slave device in the transmission cycle. The master device 40 starts transmission with the slave device 60 if the switch is set to perform offline transmission. At this time, the master device 40 measures the time from data transmission to response reception, and reports it to the maintenance monitoring device 10 via the programmable controller 30. The master device 30 stops transmission when the number of data transmissions reaches a predetermined number, for example, 100, calculates a transmission monitoring time based on the measured response time, and reports it to the maintenance monitoring device 10. The operator checks the transmission monitoring time reported to the maintenance monitoring device 10, changes the transmission monitoring time as necessary, and sets it in the master device 40. The master device 40 is set by the maintenance monitoring device 10 if a switch is set to perform online I / O transmission for exchanging I / O data with the programmable controller and reporting a transmission abnormality. The transmission cycle and the transmission monitoring time are received via the programmable controller 30, and I / O transmission is started. The master device 40 transmits data to each slave device 60 at each transmission cycle, starts a transmission monitoring timer each time the data is transmitted, stops the transmission monitoring timer when a response from the slave device 60 is received, and stops the transmission monitoring timer. The data exchange with 60 is terminated. When there is no response from the slave device 60, the master device 40 times out the transmission monitoring timer, and determines that the transmission of the slave device 60 is abnormal.
[0012]
FIG. 5 is a flowchart illustrating a transmission processing procedure of the master device. This flowchart is executed for each slave device to which data is to be transmitted in each transmission cycle. First, it is determined whether or not it is offline (S10). If it is not offline, online transmission data transmission processing is executed (S11). If the transmission / reception is completed, the transmission / reception completion flag is checked (S20). If the transmission / reception execution flag is ON, the transmission is passed. If the transmission / reception execution flag is OFF, it is determined whether the data transmission number has reached a specified value (S30). If the number of data transmissions has reached the specified value, the current value is cleared (S31). If the number of data transmissions has not reached the specified value, a data transmission process is executed (S32), a response timer is started, a transmission / reception execution flag is turned on, and 1 is added to the number of data transmissions (S33).
[0013]
FIG. 6 is a flowchart showing the reception processing procedure of the master device. This flowchart is executed when data reception for each slave device has been completed.
First, it is determined whether or not it is offline (S10). If it is not offline, online transmission data reception processing is executed (S11). If it is offline, the transmission / reception execution flag is turned off, 1 is added to the number of received data, the response timer is stopped, the current value is updated with the response timer value, and the response timer value is added to the total response time (S12). The response timer value is compared with the minimum value (S20), and when the response timer value is smaller than the minimum value, the minimum value is updated (S21). The response timer value is compared with the maximum value (S30), and when the response timer value is larger than the maximum value, the maximum value is updated (S31). Next, it is determined whether or not the number of data transmissions has reached a specified value (S40). If the number of data transmissions has reached a specified value and the number of data transmissions is equal to the number of data receptions (S50), the total response time is set to data reception. The average value is calculated by dividing by the number and written in the average value area (S51).
[0014]
FIG. 7 shows an example of an offline transmission status screen displayed by the maintenance monitoring device. On this screen, the master device performing offline transmission always reports, and the current value, the minimum value, and the maximum value of the response time are displayed. When the offline transmission is completed, the master device reports and displays a transmission monitoring time calculated based on the average value and the maximum value. If there is no problem with the set value, the operator performs a save operation. If the operator wants to change the set value, the operator changes the set value and then performs a save operation.
[0015]
【The invention's effect】
As described above, according to the present invention, the master device measures the transmission time using the actual I / O transmission system, and can set the transmission monitoring time corresponding to the I / O transmission system. This has the effect of quickly detecting an abnormality in the / O transmission system and reducing adverse effects on the system. Further, since the offline transmission is performed before the normal online I / O transmission is started, there is an effect that the state of the I / O transmission with each slave device connected to the transmission path can be easily checked.
[Brief description of the drawings]
FIG. 1 is a block diagram of an I / O transmission system of the present invention. FIG. 2 is a block diagram of a master device. FIG. 3 is a data configuration diagram of parameters related to off-line transmission. FIG. 5 is a flowchart showing a transmission processing procedure of the master device. FIG. 6 is a flowchart showing a reception processing procedure of the master device. FIG. 7 is an offline transmission status screen displayed by the maintenance monitoring device. Configuration diagram of conventional I / O transmission system [FIG. 9] Conventional time chart of normal transmission [FIG. 10] Conventional time chart of abnormal transmission [Explanation of symbols]
Reference Signs List 10 maintenance monitoring device 20 power supply device 30 programmable logic controller 40 master device 50 transmission line 60 slave device 100 central station 300 system control means 301 switch / LED
302 I / O port circuit 303 System bus connector 304 System work area 305 System control unit 306 Shared memory area 310 Transmission control means 311 Transmission work area 312 Transmission interface unit 313 Transmission connector

Claims (3)

A maintenance station, a power supply, a central station including a programmable controller and a master device, and one or more slave devices connected to the master device via a transmission line, wherein the master device is An I / O transmission system in which the programmable controller exchanges I / O data with the slave device by performing I / O transmission at regular intervals between
When the master device starts online I / O transmission with the programmable controller, the master device performs offline transmission before that and measures the time from data transmission to response reception, An I / O transmission system that reports the measurement result to the maintenance monitoring device. 2. The I / O transmission system according to claim 1, wherein the master device sets a transmission monitoring time of the maintenance monitoring device. The master device includes system control means and transmission control means,
The system control means includes an I / O port circuit connected to a switch / LED for selecting one of the online I / O transmission and the offline transmission, and an I / O data transfer between the programmable controller. A shared memory for performing exchange and transmitting / receiving a transmission cycle and a transmission monitoring time required for starting I / O transmission with the slave device with the maintenance / monitoring device from the programmable controller via a system bus. A region, a system work region for storing parameters related to offline transmission, and a system control unit that manages a series of these processes and the entire central station,
2. The transmission apparatus according to claim 1, wherein the transmission control means comprises a transmission work area for transmitting and receiving data to and from the slave device, and a transmission interface unit connected to a transmission connector for transmitting and receiving to and from the slave device. / O transmission system.

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