JPS6166497A - Recognition of dead lock - Google Patents

Abstract

PURPOSE:To minimize the dead lock time of a control by setting the answer back time at control with the aid of a parameter at every position in correspondence to each controller and monitoring sequentially its time-out at selection of a device. CONSTITUTION:A maximum responding time at every position corresponding to each controller is made resident previously as a timer parameter 9, which is loaded through a multiplexer 12 at every control output, and the time-up is sequentially monitored. Thus the recognition of answer back is made flexible even if each response time in terms of control is arbitrarily changed.

Description

[Detailed Description of the Invention] [Downstream Field of the Invention] The present invention relates to a system for controlling slave stations from a master station, and in particular, a method for efficiently recognizing answer bank times set for each device within the master station. Regarding.

[Background of the invention]

FIG. 2 shows an example of answerback monitoring for conventional control. As described in Japanese Unexamined Patent Publication No. 59-12300, conventional devices perform answer-back monitoring of control equipment by checking the coincidence of the operating position and response position, as well as checking for each type of control, for example, pump activation. In the case of a command, the maximum time from output to actual pump operation is kept as a monitoring timer value, and only when a timeout is detected, an alarm is issued as an abnormality. However, response times vary depending on the type of pump, and in cases where a time delay in abnormality detection is not acceptable, a fixed timer that does not respond to each control type may cause a certain controlled device to time out early. However, since the maximum timeout time of the specific device is set, there will be a time difference from the previous one, causing a problem in which abnormality detection will be delayed.Furthermore, the timeout state can be reset manually, so unless it is forcibly reset. , a vicious cycle ensues in which the next device cannot be selected. That is, the control data inputted from the control signal input device 1 passes through the rationality discriminator 5 and the decoder 13ft, is edited in accordance with the control parameters 6, and is sent to the slave station. On the other hand, the response data from the slave station is detected by the answerback detection circuit IO for a part of the time, and if there is a response, the control data and response data are compared, and if they do not match, a malfunction is notified. If there is no response, it is only possible to move to the next control step after manually resetting the selection.

In the figure, 2 is a master station device, 3 is a signal transmission device, 4 is a display device, 7 is a code editing process, 8 is a transmission path, and 11 is a selection cancellation circuit.

[Purpose of the invention]

The purpose of the present invention is to set an answer-back time during control as parameter 1, -' overnight for each position and unit corresponding to each control device, monitor the time act every time a device is selected, and The present invention provides a method for recognizing lock t.

[Number of inventions]

A feature of the present invention is to monitor the answerback of control at the master station by loading a timer value corresponding to the control g1 device each time the control is performed and monitoring the response time.

When a timeout is recognized, the device selection hold is automatically released to avoid deadlock and enable selection of the next device.

[Embodiments of the invention]

An embodiment of the present invention will be explained in detail with reference to FIGS. 1 and 3.

The difference with conventional devices is that the response puncture confirmation for control was done using a fixed timer or visual confirmation by humans, whereas the maximum response time corresponding to each control position is stored in advance as timer parameter 9. Each time a control output is made, the value is loaded through the multiplexer 12t and the time-up is sequentially monitored. This makes it possible to respond flexibly to N acknowledgments of answerbacks even if the response time of each control example changes arbitrarily, and to minimize the timeout delay caused by a fixed timer, that is, the delay in abnormality detection ftm. I can do things.

At the same time, during time amplifier, it becomes uncontrollable.
Conventionally, selection was manually deselected, but in the present invention, the time amplifier is used as a trigger to forcibly transition to selection deselection and cancel control.

In addition, in this case, since the timer kakunta is a parameter, it can easily respond to changes in the answerback time due to changes or conversions in the controlled equipment, especially in systems that require strict response times and abnormality detection. It is effective in systems where time delays cannot be tolerated. As shown in the flowchart in Figure 3, if the time is up,
It is assumed that the permissible answerback time of the relevant device has exceeded, and the control output is stopped via the three-state driver 14.

On the other hand, according to the present invention, by applying a trigger to the selection canceling circuit 11, it is not necessary to provide the time act check process itself for each type of control, and it is also possible to apply a trigger to the selection cancellation circuit 11. Furthermore, since the control selection is canceled when the time is up, the control deadlock time t- can be minimized.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a conventional device, and FIG. 3 is a flowchart of timeout check processing of the present invention.

Claims (1)

[Scope of Claims] 1. In a system in which a master station and a slave station are connected by a transmission path, and the master station controls target equipment that is the slave station, the maximum amount of time required from a control command to a response corresponding to each control device is as follows: The response time is stored in a ROM in advance, and the corresponding timer value is loaded every time a device is selected to monitor the response timeout. When the response timeout is detected, it is assumed that the slave station is abnormal and the device A deadlock recognition method characterized by forcibly resetting a selection to enable next selection control.