JPH0239143B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polling control method in which, when a control device sends polling signals to a plurality of devices, the polling period is delayed for devices that do not respond within a predetermined time. Conventionally, when a plurality of displays, printers, etc. 2 ₁ to 2 _o are connected to a control device that controls multiple devices, for example, a control device 1 as shown in FIG. 1, it is difficult to grasp the status of each of these devices. In order to do this, the control device 1 performs a polling operation. In other words, polling is normally done in descending order of machine number (#1→
#n) is repeated. The control device 1 performs a retry operation for devices that do not respond to the polling signal. 1 polling cycle, i.e. polling all devices 1
During the cycle, if there are many retry operations, the polling cycle becomes slow, and the response of devices that are operating normally becomes apparently slow. On the other hand, the polling cycle for non-responsive devices is made slower by a predetermined number of polling cycles than the polling cycle for normally responding devices, and the polling cycle for normally operating devices is apparently made faster. is being carried out. However, this method still has the drawback that slow polling cycles occur intermittently. Therefore, it is desirable to randomly distribute polling for unresponsive devices over multiple polling cycles. This makes it possible to make any cycle appear faster. An object of the present invention is to provide a polling control method that can randomly delay the polling cycle for unresponsive devices and effectively speed up the polling cycle for normal devices. In order to achieve the above object, the polling control method of the present invention is a polling control method in which a control device sequentially polls a plurality of devices, and delays the polling cycle for devices that do not respond within a predetermined time. The control device includes: a polling cycle counter; and a polling timing counter provided corresponding to the plurality of devices; and confirming whether the content of each polling timing counter is a specific value. (hereinafter referred to as content confirmation), and if the content of the polling timing counter is not a specific value, the polling operation is not executed and the content of the polling timing counter is incremented in the direction of decrement to correspond to all devices. The contents of the next polling timing counter are checked until the checking of the contents of the polling timing counter is completed, and if the contents of the polling timing counter is a specific value, the polling operation of the device corresponding to the polling timing counter is stopped. and when there is no response to the polling operation, the contents of the polling cycle counter are stored in a polling timing counter provided corresponding to the non-responsive device, and the value of the polling cycle counter is incremented. After making them move forward,
The contents of the next polling timing counter are checked until the contents of the polling timing counters corresponding to all devices have been checked. After checking the contents of the polling timing counters corresponding to all devices, the above The present invention is characterized in that the maximum value of the contents of a plurality of polling timing counters is set in the polling period counter and the above operation is repeated. FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention. In the figure, polling of devices 2 ₁ to 2 _o is performed by a microprocessor (μ-
This is done by executing a polling control program included in the microprogram 12 under the control of the CPU 11. The polling control program sends polling signals to the devices 2 ₁ to 2 _o via the interface adapter 14, but at this time it sets the timer 13 for response monitoring.
It monitors whether a response to the polling signal can be detected within a certain period of time, and stores the status information in the device status table 15 corresponding to the polling control program. The above configuration is for performing a polling operation similar to the conventional one. In the present invention, the control device 1 includes a polling period counter 21, and polling timing counters 2 provided corresponding to each of the devices ₂₁ to _2o .
2 ₁ to 22 _o (in FIG. 2, in order to clarify the correspondence, they are shown corresponding to the device side 2 ₁ to 2 _o ). FIG. 3 is a flowchart showing the operation of the control device in the embodiment of FIG. The operation of the control device 1 will be explained using FIG. 3. In the figure, initial values are initially set, the value of the polling cycle counter is set to "1", and the value of the polling timing counter is set to a specific value (0 in this case).
, and first, before the polling operation, the control device 1 checks the contents of the polling timing counter 22 of the device to be polled, and if the contents are not a specific value (for example, "0"),
The value is decremented by 1 and the next device polling operation is started. If all devices have been polled, the next cycle is started. On the other hand, if the value of the polling timing counter 22 is "0", a polling operation is performed,
If there is a response, the process moves on to the next device polling operation in the same manner as described above. However, if there is no response to this polling operation and there is no response even after retrying, the contents of the polling period counter 21 are transferred to the polling timing counter 22 provided corresponding to the device 2 that has become unresponsive. Set to Then, the contents of the polling cycle counter 21 are also incremented by 1. The above operation is performed for all of the devices 2 ₁ to 2 _o , and when this is completed, the maximum value of the contents of the plurality of polling timing counters 22 ₁ to 22 _o is set in the polling cycle counter 21, and the next operation is performed. Shift to polling cycle. As described above, in the present invention, the control device 1 is provided with two types of counters, a polling cycle counter and a polling timing counter, and by controlling them as described above, when there are multiple devices that do not respond, each polling It becomes possible to randomly distribute the period over a plurality of polling cycles, and it becomes possible to shorten the polling period for normal devices in any polling cycle. The following table shows an example that follows the flowchart of FIG. In the same table, for the sake of simplicity, the polling period counter 21 and each device 2 1 _to 2 _o in 6 polling cycles are shown for three devices #1 to #3.
An example of the numerical values of the polling timing counters 22 ₁ to 22 _o is shown below. In the first polling cycle, the content of the polling cycle counter 21 is initially set to 1, and the polling cycle counter 21 is initially set to 1.

【table】
All normal All abnormal Timing counter 22 ₁ to 22 _o contents to 0
Assume that as a result of a polling operation, device #1 received a response, and devices #2 and #3 did not respond. At this time, since the #1 device received a response, the content of the polling timing counter of the #1 device does not change and is "0", and the content of the polling cycle counter 21 of the #2 device does not change because there is no response. Polling timing counter 22
The polling timing counter 22 is set to 1, and the polling operation is performed in the #3 device following the #2 device, and the content of the polling cycle counter 21 is "2". The content of is "2". Then, when the processing of all devices #1 to #3 is completed, each polling timing counter 22
The maximum value "2" among the values is set in the polling cycle counter 21, and is set as the initial value of the polling cycle counter 21 for the next second polling cycle. In the second polling cycle, the initial value "2" is set in the polling cycle counter 21, and 0, 1, and 2 are set in the polling timing counters 22 of each device #1 to #3. Therefore, in this polling cycle, since the polling timing counter 22 of the #1 device is 0, the control device 1 executes the polling operation (assuming that there is a response at this time) and checks the other #2 and #3 devices. , do not perform the polling operation, subtract each value by 1, and set the contents to 0 and 1. Then, the maximum value 1 is set in the polling cycle counter 21, and becomes the initial value of the polling cycle counter 21 for the next third polling cycle. In the third polling cycle, the polling cycle counter 21 is set to an initial value of 1, and
Since the values of the polling timing counters 22 of devices #1 and #2 are 0, the polling operation is performed only for devices #1 and #2. At this time, it is assumed that #1 device has responded and #2 device has not responded. Therefore, the content of the polling timing counter 22 corresponding to the #1 device is 0, and the content of the polling timing counter 22 corresponding to the #2 device becomes 1 because the content 1 of the polling cycle counter 21 is set. On the other hand, in device #3, since the content of the polling timing counter 22 is 1, the polling operation is not executed, and the content is incremented by -1 and becomes 0.
becomes. Therefore, at the end of this third polling cycle, the value 1 of the polling timing counter 22 of the #2 device is the maximum value, so the polling cycle counter 21 is set to 1, and the polling cycle counter of the next fourth polling cycle is set to 1. 2
The initial value is 1. In the fourth polling cycle, the polling cycle counter 21 is set to an initial value of 1, and
Since the value of the polling timing counter 22 of only devices #1 and #3 is 0, the polling operation is performed only for devices #1 and #3. First, a polling operation for the #1 device is performed. At this time, it is assumed that the #1 device has responded. Next, since the content of the polling timing counter 22 of #2 device is 1, the polling operation is not executed, and the content is incremented by 1 to become 0. Next, a polling operation for #3 device is performed. At this time, it is assumed that #3 device has responded. Therefore, the contents of the polling timing counters 22 corresponding to devices #1 to #3 are all zero. Therefore, the initial value of the polling cycle counter 21 is set to 0. In the fifth polling cycle, the content of the polling cycle counter is 0, and the polling timing counters 22 of devices #1 to #3 are also all 0, so polling operations are performed for all devices #1 to #3. At this time, if there is no response from any of the #1 to #3 devices, the polling timing counter 22 of the #1 device is set to 0, the polling timing counter 22 of the #2 device is set to 1, and the polling timing counter 22 of the #3 device is set to 0. are set to 2, respectively, and the polling period counter 2 is set to 2.
The maximum value 2 is set to 1. In the sixth polling cycle, only the polling timing counter 22 of the #1 device has the content 0, so the polling operation is executed only for the #1 device, and the content of the polling timing counter 22 of the #2 and #3 devices is 0. Each is incremented by -1, and the same procedure is repeated sequentially. As is clear from the table above, #1 device is the first
There is a normal response to polling every time up to the fourth polling cycle, and there is no response in the fifth polling cycle. On the other hand, after #2 and #3 devices did not respond in the first polling cycle, #2 device was polled in the third and fifth polling cycles and both received no response, and #3 device did not respond. Polling is performed in the fifth polling cycle and there is still no response. In this way, while polling of a normal device is performed every time, the polling cycle of an unresponsive device is randomly delayed and distributed over multiple polling cycles, so that the polling cycle of an apparently normal device is This will speed up the process. This is done by setting mutually different values in relation to the number of polling cycles to be delayed for the polling timing counter of each device that has become unresponsive to the polling operation.
This is realized by incrementing the numerical value every polling cycle and polling the device when the numerical value reaches a predetermined value. In this embodiment, a polling cycle counter is used as a means for providing such a numerical value, and the maximum value of the polling timing counter in the previous polling cycle is taken as the initial value, and the value is incremented by 1 for each non-response in that polling cycle. This numerical value is effective for efficient processing, but if desired, it can be set to add an arbitrary numerical value to further delay in response to no response. Further, when the value of the polling timing counter of each device reaches 0, polling is performed in the next polling cycle, but polling may be performed when the value of the polling timing counter of each device reaches a predetermined value. As explained above, according to the present invention, when a control device sends a boring signal to a plurality of devices, a polling counter is provided in each device, and the polling cycle number that lags behind the polling counter of a non-responsive device is determined. Different numerical values are set in advance, the numerical values are incremented every polling cycle, and devices that reach a predetermined value are polled. This allows devices that are responding normally to be polled every time, and unresponsive devices to be randomly distributed over multiple polling cycles and delayed, resulting in a normal polling cycle. This can be effectively accelerated.

[Brief explanation of drawings]

FIG. 1 is a general explanatory diagram of a polling control method, FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure is a flowchart showing the operation of the main parts of the present invention. In the figure, 1 is a control device, 2 ₁ to 2 _o are devices, 11 is a microprocessor, 12 is a microprogram, 13 is a timer, and 14 is an interface. 15 is a device status table, 21 is a polling period counter, and 22 ₁ to 22 _o are polling timing counters.

Claims (1)

[Scope of Claims] 1. A polling control method in which a control device sequentially polls a plurality of devices and delays the polling period for devices that do not respond within a predetermined time, the control device comprising: A polling cycle counter and a polling timing counter provided corresponding to the plurality of devices are provided, and each of the polling timing counters is configured to confirm whether or not the content thereof is a specific value (hereinafter abbreviated as content confirmation). ), and if the content of the polling timing counter is not a specific value, the content of the polling timing counter is incremented in the direction of decrement without executing the polling operation, and the content of the polling timing counter corresponding to all devices can be checked. The content of the next polling timing counter is checked until the end of the polling process, and if the content of the polling timing counter is a specific value, the polling operation of the device corresponding to the polling timing counter is executed, and the polling operation has no effect. In the case of a response, the contents of the polling cycle counter are stored in a polling timing counter provided corresponding to the non-responsive device, and the value of the polling cycle counter is incremented in the incrementing direction;
The contents of the next polling timing counter are checked until the contents of the polling timing counters corresponding to all devices have been checked, and after checking the contents of the polling timing counters corresponding to all devices, the above-mentioned multiple A polling method characterized in that the maximum value of the contents of a polling timing counter is set in the polling period counter and the above operation is repeated.