JPH03289323A - Controlling method for serial circuit - Google Patents

Abstract

PURPOSE:To automatically decide the process to a device which is restored from an abnormal state so as to reduce the work of the operator by transmitting abnormality information to another device along with communication data when the abnormal state occurs. CONSTITUTION:For example, a plurality of devices 2-4 are connected with each other by means of a serial circuit 1 and the devices 2-4 are controlled from each other by utilizing process data. A process controlling section 11 controls a motor and a working machine and processes transmitting data to other devices in accordance with the data 12b and abnormality code 12a received from a device by a circuit controlling section 12 and inputs of a start switch, sensor, etc., directly inputted to its own device. When abnormality occurs, the section 11 transmits the state of the device which causes the abnormality to another device in the same system along with normal data. Therefore, no manual adjustment is required, because the state of the device immediately before the abnormality occurs can be recognized by the another device and the control can be restarted from the recognized state when the device is restored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a serial line, and particularly to a method of controlling a line control device and devices connected thereto during a power outage.

[Conventional technology]

In a system where a line control device is connected to each of the distributed devices and each line control device is connected via a serial transmission path to control each device, an abnormality occurs in one device or the line control device. In particular, when a power outage occurs, the device that is transmitting to that device and waiting for a response will detect an abnormality if there is no response from the corresponding line control device for a predetermined period of time. , abnormal processing was performed.

[Problem to be solved by the invention]

When an abnormality occurs in one device or line control device, the device that wants to send information such as messages or control signals to it needs to know the state immediately before the abnormality occurred in order to handle the abnormality. For example, in the machining process of a certain part, a machining command is sent from the control device to the machining machine through a serial line, the machining machine performs machining based on the command, and after the machining is completed, it sends a completion report serially. Consider a system that returns data to the control device through a line. In this system, if a power outage occurs on the processing machine side between a machining command and a completion report, the control device needs to decide what to do when power is restored depending on whether machining has been completed or not. However, in the prior art, since this cannot be determined, it is necessary to manually give a determination command to the control device. In distributed control systems using serial lines, the distance between the control device and the controlled device can be several inches, which is a major problem. For this reason, there is a method of increasing reliability by duplicating the power supply of each device, but this has the problem of increasing system cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a system line control method that can electrically transmit the current status of a device to other devices when the device is out of power or abnormal.

[Means to solve the problem]

The above purpose is that each line control device has an abnormality detection means,
This is achieved by the corresponding line control device transmitting abnormality information along with normal data to other devices when an abnormality occurs, and by providing the line control device with an operation retention means to maintain its operation for a certain period of time when a power outage is detected. achieved.

[For production]

When an error occurs, the status of the device that caused the error is sent to other devices in the system along with normal data.
Other devices can recognize the state immediately before the abnormality occurs and continue control from that state when power is restored, eliminating the need for manual correction. In addition, if the line control device's power supply fails, it will no longer be possible to transmit the state immediately before that, but by providing an operation retention means, the above transmission will be possible, eliminating the need for expensive measures such as duplication of power supplies. do not.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an example of the configuration of a parts processing process control system. Device 3. Devices 4 (which have the function of a line control device) are connected via a serial line 1, and are mutually controlled using process data. When the start switch 15 is turned on, the device 2 turns on the motor 8 to drive the conveyor 7. When the part 6 placed on it reaches the lower part of the sensor 141 of the processing machine 51, this information is sent from the device 3 to the device 2, which causes the device 2 to turn off the motor 8, stop the conveyor 7, and 51
A signal is sent via the device W3 to start processing. When the machining is completed, the device 3 transmits the completion information to the processing unit W2, and the processing unit W2 starts the motor 8 so as to send the processed part 6 to the take-out position (for example, to the right end of the figure). The device 2 also controls the processing machine 52 in the same manner.

FIG. 1 is a detailed configuration diagram of device 2 (devices 3 and 4 are also the same). The power supply unit 9 outputs a power outage signal 9c when the voltage of the input power supply 98 decreases and becomes lower than a certain constant voltage. A voltage holding unit 10 is provided to stabilize the output 9b for a certain period of time even if the input power source 9a decreases, and this has a capacity that can hold the output 9b for a sufficient period of time to transmit abnormal data. It has a built-in capacitor. The process control unit 11 controls motors and processing machines in response to data 12b received from the device inspected by the single-line control unit 12, an error code 12a, and inputs from a start switch, sensor, etc. directly input to the device itself. , performs processing such as outputting transmission data to other devices. The power outage signal 9C from the power supply section 9 and the device abnormality signal 11b from the process control section 11 are encoded by the decoder 13 and passed to the one-line control section 12 as a transmission abnormality code 13a. The contents of this abnormality code include the contents of the abnormality, that is, a power outage, other abnormality, or a code indicating that there is no abnormality.

FIG. 3 shows details of the line control section 12. The encoded transmission abnormality code 13a described above is directly transmitted to the data transfer controller 17 without going through the process control section 11.

This is because if the information is passed through the process control unit 11, other abnormalities cannot be passed to the line control unit 12 when the process control unit is abnormal. On the other hand, the transmission data l from the process control unit 11
la is stored in the transmission buffer 20, and this and the input transmission abnormality code 13a are combined into transmission data in the format shown in FIG. 4 by the data transfer controller 17, and transmitted to another device. Further, the data received from the serial line is stored in the reception buffer 19 for -1 days.
It is read out to the process control unit 11 when necessary. There is an error code indicating the occurrence of an error in the data received from another device, and when the data transfer controller 17 recognizes this, it immediately stores the error code in the error buffer 18 and issues an error interrupt 12c to the process control unit 11. . Upon receiving this, the control unit 11 reads the abnormality code from the abnormality buffer 18, compares it with the corresponding received data 12b, and determines whether the data can be used. If it is determined that it can be used, it can be used as backup data for subsequent control, and manual intervention can be omitted when an abnormality occurs.

In addition, in the system shown in Fig. 2, any device can control other devices, but for example, only device 2 is a master device that controls other devices, and the others are slave devices controlled by the master device. It is clear that the line control device for the slave device may report the status of the abnormal device to the master device when an abnormality occurs.

〔Effect of the invention〕

According to the present invention, when an abnormality occurs, abnormality information can be passed along with communication data to another device, so that the device that receives this information refers to the state immediately before the abnormality occurred and automatically performs processing for the corresponding device after the abnormality has been recovered. This has the effect that the operator's work can be significantly reduced, and the abnormality information can be transmitted without using an expensive redundant power source.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a device that implements the present invention, FIG. 2 is a diagram showing an example of the configuration of a process control system, FIG. 3 is a diagram showing a detailed configuration of a line control section, and FIG. 4 1 is a diagram showing a frame format of serial data sent to a serial line. 1... Serial line, 9... Power supply section, 10...
Voltage holding unit, 11... Process control unit, 12... Line control unit, 13... Decoder, 18... Abnormality buffer. Figure 1 Figure 2 ■ Figure ■ Figure

Claims (1)

[Claims] 1. In a serial line control method for connecting a plurality of locations via one serial line and communicating data between each device, an abnormality detection means for detecting an abnormality in each device. A serial line control method characterized in that a device detecting an abnormality by the means transmits information indicating the details of the abnormality together with data to another device. 2. Provide a voltage holding means that can supply power to the device for more than a certain period of time in the event of a power outage to the device, and detect that the power outage has occurred during the specified period of time after the power outage occurs. 2. The serial line control method according to claim 1, wherein the information indicating the content is transmitted to another device. 3. The serial line control method according to claim 2, wherein the voltage holding means is constructed using a capacitor that is charged during normal operation and discharged during a power outage. 4. In a serial line control method in a distributed control system in which multiple sets of devices each consisting of a master or slave communication device and a process control device are connected on a single serial line, it is possible to A serial line control method characterized in that a slave communication device of a set simultaneously reports normal communication data and abnormality information to a master communication device via a serial line. 5. Provide a voltage holding means capable of supplying power to the slave communication device for a certain period of time or more when the power supply to the slave communication device is interrupted, and prevent the power outage from occurring during the certain period of time after the power outage occurs. 5. The serial line control method according to claim 4, wherein the abnormality information is reported to the master communication device.