JPH0291703A - Multiplex transmission method for programmable controller - Google Patents

Abstract

PURPOSE:To enable efficient multiplex transmission by setting a transmitter address continuously, checking on-line information at a data transmission destination corresponding to the multiplex constitution of a transmission origin station, and detecting a transmitter in control operation and sending data. CONSTITUTION:The addresses of transmitters 21 and 22 are set to successive addresses (n) and n+1 for each multiplex station. Further, the transmitters 21 and 22 of the multiplex station are provided with status maps indicating whether the transmitters 21 and 22 are normal or abnormal and when data is sent from another station 7 to the multiplex station 1, the normal/abnormal statuses of multiplexing transmitters are checked in order from the transmitter having the head address of the multiplex station and the data is sent to transmitters having normal statuses S0 and S2...Sn. Consequently, any special hardware for multiplexing is not provided to the transmitters 21 and 22 and efficient multiplex transmission is carried out without providing any station address with a redundant bit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a programmable controller multiplex transmission method in which a backup system is configured by multiplexing data transmission of programmable controllers.

(Prior Art) In recent years, with the spread of programmable controllers, multiplex systems such as duplication and triplexing have come to be used in order to further improve reliability. Also F
With the advent of A, systems are becoming mainstream in which a large number of programmable controllers placed in a factory are connected by data transmission equipment and are centrally managed from a central monitoring and control room. Multiplexing systems have been used, including

2 including the data transmission device of the programmable controller
An example of the configuration of the weighting system is shown in FIG.

In FIG. 5, 21.22 is a data transmission device (hereinafter simply referred to as a transmission device), 31.32 is a programmable controller (hereinafter referred to as a PC), and 4 is a bus changeover switch, which allows two types of communication between the PC and the transmission device. It constitutes a control station 1 as a heavy system.

Further, 5 is an input/output module, 6 is a transmission path of the transmission devices 21 and 22, and 7 is another control station which is also composed of a PC, a transmission device, and an input/output module.

The duplication station 1 is usually one of two sets of PC and transmission device connected to an input/output module 5 by a bus changeover switch 4 to control the corresponding process, and also to control other processes via a transmission path. It sends and receives data to and from the control station 7.

When the PC 31 and the transmission device 21 are controlling, the bus changeover switch 4 is switched so that the PC 31 and the input/output module 5 are connected, and the PC 31 also displays the message "The input/output module is connected and under control." It sends a status signal saying "Yes", and sends a status signal "'The input/output module is not connected and not under control" to the PC 32.

Each of the transmission bags Wi21 and Wi22 determines whether the data sent via the transmission path 6 is for its own station, depending on its own station address. Station address configuration is used.

In FIG. 6, ADRn is the station address of the transmission device 21, ADRn' is the station address of the transmission device 22, and the station addresses ADRn, AD
Rn' both indicate the station address n, but if the most significant bits are not compared, the two transmission devices are redundant so that they both have the station address n.
If the most significant bits are compared, the two transmission devices will have station addresses n and n', which will be determined. That is, the transmission devices 21 and 22 must have such a function in order to support a duplex system.

The PC 31 sends a status signal indicating that it is "under control" and a status signal indicating that it is a "duplex system" to the transmission device 21, and responds to the transmission data for the station address n.

On the other hand, the PC 32 sends a status signal indicating "not under control" and a status signal indicating "1' is a duplex system" to the transmission device 22, and does not respond to transmission data for station address n.

At this point, an abnormality occurs in the PC 31 or the transmission device 21.

When control or transmission becomes impossible, the PC 31 detects an abnormality and outputs a switching request to the bus changeover switch 4. After switching the bus connection so that the PC 32 and the input/output module 5 are connected, the bus changeover switch 4 sends a status signal to the PC 31 indicating that "the input/output module is not connected and is not under control", and the PC 32 receives the "input/output module". It sends a status indicating that the module is connected and under control, and switches control to the PC 32 and transmission device 22 side.

At this time, PC31 is a transmission bag! ! ! 21, the PC 32 sends a status signal indicating "not under control" and a status signal indicating "duplex system" to the transmission device 22, and sends a status signal "currently under control" and a status signal "duplex system" to the transmission device 22. Send status signals.

This switches the transmission device 22 to respond to transmitted data for station address n, thus continuing control and data transmission.

(Problem to be Solved by the Invention) The above method has the advantage that the other control station 7 can transmit data to the duplex system without any special considerations, but the method requires the transmission device to compare the most significant bits. It is necessary to provide a switching function to enable or disable the transmission, and since the transmission speed of FA transmission equipment is fast, a hardware response is required.

In addition, since one bit of the station address is made redundant, the station address setting range is halved compared to the number of set bits, and if you use a triplex or higher multiplexing system, the number of redundant bits increases further, and the station address The setting range is reduced and becomes inefficient with respect to the capacity of the transmission device.

The present invention has been made in consideration of the above problems, and uses online information of each station in the transmission system, which the transmission equipment usually has as RAS information, to continuously update the transmission equipment addresses of the multiplex system. , the data source checks online information according to the multiplexing configuration of the destination station, detects the transmission device being controlled, and sends data, thereby making the transmission device compatible with multiplexing. It is an object of the present invention to provide an efficient and economical multiplex transmission method for programmable controllers that does not require special hardware or provide redundancy bits in station addresses.

[Structure of the invention]

(Means and operations for solving problem 111) Generally, in data transmission devices used for FA, the transmission right is often rotated between each transmission device, and in such cases, the transmission right is Information on whether the transmission device is normal or abnormal is created/updated in a 1-bit/station bitmap format according to the address, and is used as control information and RAS information for passing transmission rights, as shown in Figure 2. Each transmission device has a
Transmission control for multiple systems is performed using an abnormality status map.

That is, the present invention provides a programmable controller multiplex transmission method for transmitting data between control stations including stations multiplexed by a plurality of programmable controllers and a plurality of transmission devices.
In addition to setting the addresses of each transmission device to consecutive addresses for each multiplexing station, each transmission device is provided with a status map that indicates the normality/abnormality of each transmission device in the multiplexing station, and data is transmitted from other stations to the multiplexing station. When transmitting, check the normal/abnormal status for the number of multiplexed stations in order from the transmission device with the first address of the multiplexed station.

Data is transmitted to the transmission device in normal status,
This allows efficient multiplex transmission without providing special hardware for multiplexing in the transmission device and without providing redundant bits in the station address.

(°Example) An embodiment of the present invention is shown in FIG.

FIG. 1 is a system diagram showing an example of the case where the present invention is applied to a control station with a duplex configuration, where 1 is a control station of a duplex system; 21.22
is a transmission device, and is set at consecutive addresses n and n+1.

Also, 31 and 32 are bus changeover switches, PCl4 is an input/output module, 6 is a transmission line, and 7 is another control station.

FIG. 2 shows an example of the configuration of a status map showing the normality/abnormality of each transmission device in the system that each transmission device has, and 81 to S n+1 are the statuses of each transmission device,
1 indicates normal and O indicates abnormality.

Here, the subscripts 1 to n+1 indicate the address of each transmission device, and in FIG. 2, (s o , s 1) −< S 2 ,
S3) -(S4=Ss)...(Sn, Sn+z
) indicate the status of each duplex station.

In addition, FIG. 3 shows the PC of another control station 7.
FIG. 4 is a flow chart showing the operation of the command.

As mentioned above, the station under control during transmission to the duplex system is identified by checking the normal/abnormal status of the transmission device, and the other control station 7 uses a sequence command to transmit to the duplex system. When performing this, a 5END instruction as shown in FIG. 3 is used.

The 5END command has a transmission parameter area and a status area for storing transmission results as work areas.
In Figure 3, the beginning of the transmission parameter area is RWOOO.
, specify the status area as RWOIO, and use RWOOO
indicates the address of the work area within the PC.

The transmission parameter area occupies an area of several words, and stores the address of the transmission partner station and the contents of multiplexed transmission information of the transmission partner station (for example, data read from the partner station, data written to the partner station, etc.).

The 5END command interprets this transmission parameter.

Creates a transmission text and requests its own station's transmission device to transmit it to the specified partner station.

Control station 7 to duplication station 1
The operation of the 5END command when transmitting to the 5END command will be explained using the flowchart of FIG.

First, in step SP1, the transmission parameter address specified by the 5END command is retrieved, and based on this address, the multiplexing setting information of the partner station is read out in step SP2.

Next, in step SP3, the destination station transmission device address is read, and in step SP4, whether the destination station transmission device address is normal or
Check abnormal status.

If normal, a transmission text for the other station is created in step SP8, and a transmission request is set in the transmission device of the own station in step SP9. If abnormal, the number of multiplexing is decremented by 1 in step SP5, and the transmission text is sent to the other station in step SP6. Increment the transmission device address by 1.

Next, in step SP7, it is checked whether the number of multiplexing is zero. If it is a single layer system, the number of multiplexing will be zero,
Step 5 Go to PII, set the error code of the abnormality of the partner station in the status area, and complete the command with an error.

If it is determined in step SP7 that duplication or higher is specified, the process returns to SP4 again to check the normal/abnormal status of the next transmission device address.

If normal, proceed from step SP8 to SF3, create a transmission text and set a transmission request, and if abnormal, proceed to step SP5. At SP6, the number of multiplexes is decremented by 1, and the destination station transmission device address is incremented by 1.

In this way, in steps SP4 to SP7, the normal/abnormal status check is repeated until a normal transmission device is detected for the destination station address specified by the transmission parameter up to the number specified for multiplexing, and a normal transmission device is detected. Then, use that address to create a transmission text.

If all of the specified multiplexing times are found to be abnormal, an error hood indicating an abnormality in the partner station is set in the status area in step 5 PIO, and the command is completed with an error.

If the normal transmission is completed, a normal code is set in the status area in step 5 PIO to complete the command normally.

〔Effect of the invention〕

As explained above, according to the present invention, the transmission device addresses of the multiplexing stations are set continuously, and the multiplexing specification is managed using the 5END command.

A multiplex system can be easily configured without providing special hardware for multiplex configuration in the transmission device, and the number of multiplexes can be freely set for each control station, providing flexibility. Efficient and economical multiplex transmission of programmable controllers becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a duplex transmission method showing an embodiment of the present invention, FIG. 2 is a diagram showing the structure of station normal/abnormal status data, and FIG. 3 is a diagram showing an example of a 5END command. FIG. 4 is a flowchart showing the operation of the 5END command, FIG. 5 is a system configuration diagram showing an example of a conventional duplex transmission method, and FIG. 6 is a diagram showing an example of a conventional stage 1 address configuration. 1.7... Control station 4... Path changeover switch 5... Input/output module 6... Transmission lines 21, 2
2...Data transmission devices 31, 32...Programmable controller (PC
) Agent Patent Attorney Yoshiaki Inomata (and 1 other person) No.! fig. fig.

Claims (1)

[Claims] In a multiplex transmission method for a programmable controller having a plurality of programmable controllers configured in a multiplexed configuration, each of which transmits data between stations including a multiplexing station coupled to a transmission path via a transmission device, each transmission device addresses are set as consecutive addresses for each multiplexing station, and a status map indicating the normality/abnormality of each transmission device of the multiplexing station is provided for each transmission device, when transmitting data from another station to the multiplexing station. is a programmable controller multiplex transmission characterized in that the normal/abnormal status of a specified number of multiplexing stations is checked in order from the transmission device at the first address of the multiplexing station, and data is transmitted to the transmission device with the normal status. Method.