JPS60239150A - Network system of programmable controller - Google Patents

Abstract

PURPOSE:To use in common a storage device and an input/output device of a programmable controller by adding a supervisory control function of a network executed by a supervisory station to a transmission/reception station and executing the job of the supervisory station during the pause of the job of a transmission/reception station. CONSTITUTION:Plural programmable controllers 21 having transmission/reception stations 22, 23 are connected in a ring or loop form as shown in the figure by transmission lines 24 in the network system. Moreover, a transmission error detecting circuit 31 and a phase correction circuit 35 are added as shown in the figure to the circuit of the conventional transmission/reception station 22 in the transmission reception station 23, and then the transmission reception station 23 executes the supervisory control of the network executed by a conventional supervisory station 2 together. It is to correct the delay time that an output signal of a changeover gate circuit 39 is given to the phase correction circuit 35 especially because the delay time of the entire ring form network does not correspond to an integral number of multiple of the transmission signal in general.

Description

[Detailed Description of the Invention] Technical Field> The present invention provides a monitoring station on a transmission path such as an optical fiber that initializes and starts communication, and detects abnormalities in the transmission state, and a data transmission/reception intelligence. The present invention relates to a local area network system in which a plurality of programmable controllers each having a transmitting/receiving station are arranged.

<Prior art> The local area network system for programmable controllers is a system in which multiple programmable controllers are connected via optical fibers to enable data transmission and reception between controllers over relatively short distances. , for example, when automatically controlling a factory production line (by organically combining information from individual equipment,
This allows for centralized management of production information.

As shown in FIG. 5, for example, this type of network system that has been proposed in the past involves connecting a plurality of programmable controllers 4 equipped with a monitoring station 2 and a transmitting/receiving station 3 in a ring or loop using a transmission path l such as an optical fiber. It is connected to a type.

As shown in Fig. 6, after the power is turned on, the monitoring station 2 initializes the network after initializing its own station, and when the famous station becomes able to communicate, it sends a control word to permit transmission to the node work. Then, start Nodowork. After that, the period of the signal on the network and whether or not the control word to permit transmission is present on the odd work within a certain period of time are checked, and if either one is not satisfied, it is considered as a transmission error and communication is restored immediately. Start work on.

When communication is restored, control is performed to restart the network and resume communication, and the specific circuit configuration is as shown in FIG.

That is, this monitoring station 2 includes a signal conversion circuit 5 that converts an optical signal into an electrical signal, a phase adjustment circuit section 6 for input signals and output signals including a DPLL, and a signal that maintains the same level for a period longer than the period of the transmission frequency. An abnormality detection circuit 7 that uses the property that there is no error in the input signal due to the Manchester code, a code conversion section 8 that converts the Manchester code into the NRZ code Kf, another signal conversion circuit 9 that converts the electrical signal into an optical signal, and the phase Correction circuit 10, another code converter 1 that converts NRZ code to Manchester code
1. Ink face circuit 12, which transmits data etc. read out from storage unit 4 to the network according to a certain procedure or receives signals from the network based on [control unit] 3; In response to a control signal from the ink face circuit 12 and the control section 3, the signal from the code conversion section 8 is converted to another code conversion section 1.
It is composed of a switching gate circuit 15 and an input/output circuit 16 for transmitting signals to or from the ink face circuit 12 to the code conversion section 11, and a ring circuit between the signal conversion circuits 5 and 9. used in conjunction with type networks.

On the other hand, the transmitting/receiving station 3 performs the network initialization under the leadership of the monitoring station 2 after the power is turned on and initialization of the transmitting/receiving station 3 is completed as shown in FIG. Thereafter, if data addressed to the local station arrives, it is received and processed, and if necessary, transmitted to the connected programmable controller 4. Also, if there is data from the controller 4, it is processed, temporarily stored in the storage device, and a request flag for communication request is set. 0 If the request flag is set, the data is waited for to receive the transmission right to send data to the network. Send data. When the transmission is completed, the transmission right is returned to the network and control operations such as removing the request flag are executed.

Next, the specific circuit configuration of the transmitting/receiving station 3 will be explained based on FIG. 9 (the same parts as the configuration in FIG. 6 are denoted by the same reference numerals). 5, 9, phase adjustment circuit section 6, code conversion section 8, 11
, ink face circuit 12, control section 13, storage section 14,
It is composed of a gate circuit 15 and an ink face circuit 17, and the ink face circuit 7 side is connected to the programmable controller 4, and the signal conversion circuit 5 is connected to the programmable controller 4.
．． The 9 side is used by connecting to a ring network.

In this way, in conventional networks, the monitoring station 2 is installed independently on the transmission path to constantly monitor the transmission status, and the monitoring station 2 sets the initial value to each transmitting/receiving station 8 at the time of initializing communication. input to monitoring station 2, or monitoring station 2
The input/output device 20, which is used to display the abnormal state detected by the system and notify alarms, is connected to the control unit 13 of the transmitting/receiving station 3 connected to the network via the input/output synchronizing circuit 18, as shown in the 10th diagram. It is connected via face 19.

However, in such conventional network systems, the input/output device 20 connected to the transmitting/receiving station 8 can be used only after communication with the transmitting/receiving station 3 is established. A special input/output device is required when inputting the initial values of each transmitting/receiving station 3 into the system, or when notifying the monitoring station 2 of an accident when communication becomes impossible due to an accident.

Furthermore, as mentioned above, with this method, it is necessary to separately install a storage device and an input/output device for recording and displaying transmission abnormalities and inputting setting values, which inevitably complicates the system configuration. Therefore, there is a risk that the cost will be high, and there are also problems in that these devices require a large installation space.

Purpose> The present invention has been made in view of such conventional problems.
The purpose of this is to add the network monitoring and control function performed by the monitoring station to the transmitting/receiving station, and by having the monitoring station perform the work in between the transmitting/receiving station's work, the storage device and input/output device of the programmable controller The object of the present invention is to provide a highly rational programmable controller network system that solves the above-mentioned conventional problems by making it possible to use both controllers.

<Example> The present invention will be explained in detail below based on the drawings.

FIG. 1 is a diagram showing a network system of a programmable controller according to the present invention.

In the figure, 2] is a programmable controller, 22
As explained in Figures 8 and 9, data transmission and
As explained in FIG. 6, the transmitting/receiving station 23 that performs reception is responsible for network initialization, activation, abnormality detection,
The transmission/reception station 24 is equipped with the above-mentioned monitoring station functions such as display, recording, and communication recovery work, and is a transmission line made of a plastic optical fiber or a quartz-based optical fiber.

In the network system according to the present invention, a plurality of programmable controllers 21 having the above-mentioned transmitting/receiving stations 22 and 23 are connected in a ring or loop shape through a transmission line 24 as shown in the figure, and the input/output device 25 of the controller 21 is It is connected via the ink face 26 to a transmitting/receiving station 230 having a control function of the monitoring station and to the control section 27, and further connected to the network via an input/output synchronization circuit 28.

Next, the specific circuit configuration and operation of the transmitting/receiving station 23 according to the present invention will be explained based on FIGS. 3 and 4.

In FIG. 3, 29 is a signal conversion circuit that converts an optical signal into an electrical signal, 30 is a phase adjustment circuit that adjusts the phase of an input signal including a DPLL and an output signal, and 31 is a period of a transmission frequency in the case of a Manchesv code. 32 is a code conversion circuit that converts the Manchezov code into an NRZ code; 38 is a code conversion circuit that converts the electrical signal into an optical signal; A signal conversion circuit that converts into a signal, 34 is NRZ
A code conversion circuit converts a code into a Manchesv code, 35 is a phase correction circuit, and 36 is a phase correction circuit that transmits data read out from the storage unit 38 by the control unit 37 to the network according to a certain procedure, or from the network. Ink face circuit for receiving signals of 39
In response to the control signals from the ink face circuit 36 and the control unit 37, the signal from the code conversion unit 32 is sent to the phase correction circuit 35, or the signal from the ink face circuit 36 is sent to the phase correction circuit. 35 is a switching gate circuit for transmitting signals, and 40 is an ink 7 chair circuit that controls the transmission and reception of signals with the programmable controller.

In this way, the above transmitting/receiving station 23 is different from the conventional transmitting/receiving station 2.
A transmission abnormality detection circuit 31 and a phase correction circuit 35 are added to the circuit No. 2 as shown in the figure, and therefore, this transmitting/receiving station 28 also performs the monitoring and control of Neso-i Work, which was performed by the conventional monitoring station 2. It is configured so that it can be used.

In particular, the output signal of the switching goo 1 circuit 39 is transferred to the phase correction circuit 85.
The reason for this is to compensate for the fact that the delay time of the entire general KIJ song network does not correspond to an integral multiple of the transmission signal.

Next, the operation will be explained based on FIG.

This transmitting/receiving station 23 mainly performs the operation of an original transmitting/receiving station when communication is being performed normally, and mainly performs the operation of a monitoring station when communication is abnormal, including network initialization. When deaf communication is occurring normally, we are looking for abnormalities in the transmitted signal.

First, when the power is turned on, it initializes its own station and the network, and when it is finished, it sends a control word that allows transmission to the network, sets a timer to check the time interval for receiving the transmission right, and starts the network ( n-1, n2) When the nth data is received, the received transmission right is transmitted and the reception count counter is cleared. If the data is addressed to the own station, it is received and processed, the state of the communication request riffing lag is determined, and the OFF
In this state, if there is any data from the programmable controller 21, the programmable controller 21 receives the data, stops the crawler, turns on the request flag, and enters step n+7 (n3 to n9). Note that if it is determined in step n8 that the data is not from the programmable controller 2I, the process proceeds to step n+4.

If the request flag is in the ON state at step n7, the process advances to step n10 to wait for reception of a transmission right, and upon reception, data from the programmable controller 21 is transmitted. When the transmission is finished, set the request flag to 0FFI.
,, returns the transmission right to the network and resets the timer. Furthermore, the reception number counter of the received transmission right is cleared (n+o to n+a).

Next, it is determined whether the period of the transmission signal is normal or not. This determination is executed even when the received data is not from the programmable controller 21, but if the result is abnormal, steps n]9 to n'2] The process proceeds to record the abnormality in the memory of the programmable controller 21, display the fact using the display device of the controller, and execute communication recovery work. If the recovery is not possible, the communication failure is recorded in the memory of the controller, and at the same time, a communication failure alarm is generated using the same speaker (n22, 23).
).

On the other hand, in step n14, if it is determined that the transmission right is normal, it waits for reception of the transmission right, and when it is received, it determines the state of the request flag, and if it is in the OFF state, it re-centres the timer and the number of times the transmission right has been received. Clear the counter and return to step n2 (Hl 5 to n 18)
oAlso, in step n15, if it is determined that the transmission right is in danger of being received, then the reception of the received transmission right is determined. Then, it is determined whether the content of the reception number counter of the received transmission right is the numerical value "1" or not, and if not, the content of the reception number counter of the received transmission right is set to "]" and the process proceeds to step n2. return. If the content of the counter is 61'', the process advances to step n20.

In other words, it is necessary to check whether the transmission right can be received within a certain period of time, and to use the property that the received transmission right always disappears after going around the ring once, and to monitor the transmission status after receiving the received transmission right. , network abnormality is detected by checking whether a received transmission right is not received twice in a row.

In this way, the system of the present invention does not install the monitoring station independently on the network, but adds the network monitoring and control function to the transmitting/receiving station connected to the programmable controller, so it has the following excellent advantages. It can be effective.

(1) Initial values for each transmitting and receiving station can be set in the monitoring station before communication is established using the input device of the programmable controller.

(Even if communication becomes impossible due to a No. 21 accident, notification of the accident can be made using the input device of the controller.

(31) The output device and storage device of the above controller can be used to display, alarm, and record transmission abnormalities.

(4) Since the input/output device and storage device of the programmable controller can be used, control of input to the monitoring local section, storage and output of transmission abnormality contents, etc. can be placed under program control of the controller.

In other words, the input/output and storage can be controlled by the controller program, thus simplifying the system configuration procedure.

(5) Since a dedicated input/output device and storage device are not required, a very inexpensive network can be provided.1. Effects> As explained in detail above, the network system of the programmable controller according to the present invention is capable of transmitting and receiving data. In addition to the data transmission/reception control function, the network monitoring and control function carried out by the monitoring station is added to the station, so that all of the above-mentioned conventional problems can be eliminated.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the method of the present invention, Fig. 2 is a diagram showing the connection state of the Margram controller in the same method, Fig. 3 is a specific block circuit diagram of the transmitting/receiving station according to the method of the present invention, and Fig. 4 is a diagram showing the connection state of the Margram controller in the method. is an operation flowchart of the transmitting and receiving station, FIG. 5 is a diagram showing the conventional method, FIG. 6 is an operation flowchart of the monitoring station, FIG. 7 is a block circuit diagram of the monitoring station, and FIG. 8 is a diagram showing the operation of the transmitting and receiving station 9 is a block circuit diagram of a transmitting/receiving station, and FIG. 10 is a diagram showing the connection state of input/output devices in a conventional system. 21 is a programmable controller, 22 and 23 are transmitting/receiving stations, and 24 is a transmission line. , 25 is an input/output device, 29.33 is a signal conversion circuit, 30 is a phase adjustment circuit, 31 is a transmission abnormality detection circuit, 32.34 is a code conversion circuit, 35 is a phase correction circuit, 36 is an ink face circuit, and 37 is a control unit, 38
is the storage section, 39 is the switching gate circuit, 40 is the ink face circuit agent, patent attorney Yoshihiko Fukushi (and 2 others) 2<
', / [2] Figure 2 Figure n Figure 5 Figure 7 Figure 8

Claims (1)

[Claims] l In a network system in which a plurality of programmable controllers are arranged on a transmission path, each of which has a monitoring station that initializes and starts communication, and detects abnormalities in the transmission status, etc., and a transmitting/receiving station that transmits and receives data, etc. A network system for a programmable controller, characterized in that at least one of the transmitting and receiving stations has a network monitoring and controlling function performed by the monitoring station in addition to a data sending and receiving control function.