JP2010032776A - Seven segment display, its light quantity control unit and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the power consumption in a seven segment display depending on its situation. <P>SOLUTION: The seven segment display has: a common signal generator circuit 1 to output the common signal to control the sequential lighting of each digit; a light quantity setup register 5 which can set up the lighting period shown by the common signal; a counter 6 to output the normal state continuing time of the arranged object device or the elapsed time after the last operation ends as a first measurement period and to output the mask command signal by reducing a second measurement period as the value to show the light quantity set up according to the first measurement period for every clock period; a mask signal generator circuit 7 to generate the mask signal for reducing the length of each lighting period within each digit scanning period in response to the mask command signal; and a processor 4 to set up the second measurement period as the light quantity setup value according to the first measurement period in the light quantity setup register 5 and to generate the combined common signal to use as an alternative of the common signal by combining the common signal and the mask signal together. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seven-segment display device, a light amount control device thereof, and a light amount control method.

  The 7-segment display device displays Arabic numerals, alphabets, symbols, and other characters from 0 to 9 by selectively lighting up each of the 8 light-emitting segments of Arabic numerals composed of 7 light-emitting segments. The 7-segment display unit corresponding to the required number of digits according to the application is arranged in parallel.

  The 7-segment display device is arranged in various control devices such as a servo amplifier or a numerical control device that is a control device of a servo motor, for example, and various setting values, operation states, output values, etc. of the target device. Used to display information.

  FIG. 4 is a block diagram showing a schematic configuration of a 7-segment display device and its control device.

  As an example, the 7-segment display device 2 shown in FIG. 4 is a display device having 5-digit 7-segment display units 21 to 25 and should be displayed on the 7-segment display units 21 to 25 of each digit as its control device. A data signal generation circuit 3 that outputs character data as a data signal, and a common signal generation circuit 1 that outputs common signals 1 to 5 for controlling the sequential lighting of the 7-segment display units 21 to 25 of each digit are provided. .

  The seven light-emitting segments constituting the 5-digit 7-segment display units 21 to 25 are usually turned on by emitting light using LEDs.

  In the example shown in FIG. 4, the data signal generation circuit 3 outputs an 8-bit data signal to supply character data to be displayed to the 5-digit 7-segment display units 21 to 25, and generates a common signal. The circuit 1 outputs common signals 1 to 5 having a total of 5 bits in order to control the sequential lighting of the 5-digit 7-segment display units 21 to 25.

  FIG. 5 is a timing chart showing signal waveforms of a data signal and a common signal used in the 7-segment display device.

  The data signal is a signal as character data indicating the content of information to be displayed. Based on this data signal, lighting of each of the seven light emitting segments constituting the five-digit seven-segment display units 21 to 25 is performed. And turn-off are controlled.

On the other hand, the common signals 1 to 5 are signals for controlling the sequential lighting of the 5-digit 7-segment display units 21 to 25, and the 7-segment display units 21 to 25 of each digit have the corresponding common signals 1 to 5 respectively. The light source is turned on during the low level period and is turned off during the high level period. In the example of FIG. 5, the scanning period _{T C} of the 5-digit 7-segment display portions 21 to 25, the lighting period _{T D} for each digit 7-segment display portions 21 to 25, a 1/5 from _{T C} ing.

  As can be seen from the above control of the common signal, the 7-segment display units 21 to 25 of each digit of the 7-segment display device repeats blinking at regular intervals, but the blinking cycle is very short. Because it blinks rapidly, it appears to be continuously lit by human eyes.

Brightness of lighting of each digit 7-segment display portions 21 to 25 is determined by the length of a lighting period T _D occupying the scanning period T _C.

As a display method of the 7-segment display device, as described above, by selectively lighting each of the 7 light-emitting segments, characters such as Arabic numerals, alphabets, and symbols from 0 to 9 are displayed. Although it is a normal display method, as another display method, a display method for performing analog display in which a numerical value is converted into a figure has been proposed so far (see, for example, Patent Document 1).
JP-A-9-146478

As described above, the brightness of the lighting of the 7-segment display section of each digit, although the determined by the length of the lighting period T _D occupying the scanning period T _C, in a conventional 7-segment display, 7-segment display Regardless of the operating state of the servo amplifier that is the control device of the servo motor, etc., the presence or absence of operation, etc., the 7-segment display section of each digit is always lit at a constant brightness Yes.

  The information displayed by the 7-segment display device includes important information, but the operation state of the control device or the like in which the 7-segment display device is arranged is continuously normal and stable. In addition, in a state in which no operation is performed on the control device or the like, the display content displayed by the 7-segment display device is not particularly noticeable, and therefore, the 7-segment display of each digit always at a constant brightness. It is a waste of power consumption to keep the part lit.

  However, no conventional 7-segment display device has a configuration for adjusting the lighting brightness of the 7-segment display portion of each digit according to the situation, and the control device in which the 7-segment display device is arranged As long as the power is turned on, the 7-segment display section of each digit is always lit at a constant brightness.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a 7-segment display device having a configuration capable of appropriately reducing power consumption according to the situation, its light amount control device, and light amount control. Is to provide a method.

According to the 7-segment display device according to one aspect of the present invention,
A multi-digit 7-segment display,
A data signal generating circuit for outputting character data to be displayed on the 7-segment display section of each digit as a data signal;
A common signal generating circuit for outputting a common signal for controlling the sequential lighting of the 7-segment display portion of each digit;
A light amount setting register that can set a light amount setting value set as a lighting period indicated by the common signal between a maximum light amount setting value as an initial value and a predetermined minimum light amount setting value;
The continuation time of the normal operation state of the arranged target device or the elapsed time from the end of the last operation is measured and output as the first measurement time, and the light amount setting value set according to the first measurement time A counter that outputs a mask command signal for commanding generation of a mask signal by subtracting the second measurement time as a value indicating the value for each clock period in synchronization with the clock signal;
A mask signal generating circuit for generating the mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display portion of each digit according to the mask command signal;
In accordance with the first measurement time, the second measurement time is set in the light amount setting register as the light amount setting value, and the common signal and the mask signal are combined to be used as a substitute for the common signal. A processing device for generating a common signal;
A 7-segment display device is provided.

According to the light quantity control device of the 7-segment display device according to one aspect of the present invention,
A data signal generating circuit for outputting, as a data signal, character data to be respectively displayed on the 7-segment display unit of each digit of a 7-segment display device having a multi-digit 7-segment display unit;
A common signal generating circuit for outputting a common signal for controlling the sequential lighting of the 7-segment display portion of each digit;
A light amount setting register that can set a light amount setting value set as a lighting period indicated by the common signal between a maximum light amount setting value as an initial value and a predetermined minimum light amount setting value;
The continuation time of the normal operation state of the arranged target device or the elapsed time from the end of the last operation is measured and output as the first measurement time, and the light amount setting value set according to the first measurement time A counter that outputs a mask command signal for commanding generation of a mask signal by subtracting the second measurement time as a value indicating the value for each clock period in synchronization with the clock signal;
A mask signal generating circuit for generating the mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display portion of each digit according to the mask command signal;
In accordance with the first measurement time, the second measurement time is set in the light amount setting register as the light amount setting value, and the common signal and the mask signal are combined to be used as a substitute for the common signal. A processing device for generating a common signal;
A light amount control device for a 7-segment display device is provided.

  In each of the above-described configurations of the 7-segment display device and the light amount control device thereof according to one aspect of the present invention, the first level period of the common signal may define the lighting period of the 7-segment display unit.

  The mask signal may be a signal that may have a second level period that expands and contracts according to the second measurement time in a part of a period corresponding to the first level period of the common signal. .

  The processing device may generate the combined common signal having a first level period having a length equal to or shorter than the first level period of the common signal by AND-combining the common signal and the mask signal. .

  In addition, when the first measurement time reaches a predetermined time, the processing device gradually reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. Good.

  Alternatively, when the first measurement time reaches a predetermined time, the processing device instantaneously reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. Good.

  The duration of the normal operation state of the target device is measured by the processing device monitoring an alarm table that manages the presence or absence of an alarm that is activated in response to the occurrence of various abnormal operations of the target device. Good.

  The alarm table may be configured by software.

  Alternatively, the alarm table may be configured by hardware.

  The 7-segment display device and the light amount control device thereof according to one embodiment of the present invention may further include a clock signal generation circuit that supplies the clock signal that defines a cycle of the common signal and the combined common signal. .

  Alternatively, the counter may include a clock signal generator that supplies the clock signal that defines the period of the common signal and the combined common signal.

According to the light amount control method of the 7-segment display device according to one aspect of the present invention,
The maximum light quantity as an initial value is the light quantity setting value set as the lighting period indicated by the common signal for controlling the sequential lighting of the 7-segment display section of each digit of the 7-segment display device having a multi-segment 7-segment display section The process of setting to the set value,
A process of measuring the duration of the normal operation state of the target device in which the 7-segment display device is arranged or the elapsed time from the end of the last operation as the first measurement time;
In accordance with the first measurement time, a process of setting the light amount setting value as a second measurement time as a value indicating the light amount setting value between the maximum light amount setting value and a predetermined minimum light amount setting value;
Generated by subtracting the second measurement time for each clock period in synchronization with the clock signal to shorten the length of each lighting period occupying the scanning period of the 7-segment display section of each digit The process of
Combining the common signal and the mask signal to generate a combined common signal used as an alternative to the common signal;
A seven-segment display device light amount control method is provided.

  In the above-described configuration of the light amount control method for the 7-segment display device according to one aspect of the present invention, the first level period of the common signal may define the lighting period of the 7-segment display unit.

  The mask signal may be a signal that may have a second level period that expands and contracts according to the second measurement time in a part of a period corresponding to the first level period of the common signal. .

  In the process of generating the composite common signal, the common signal and the mask signal are AND-combined to generate the composite common signal having a first level period that is less than or equal to the first level period of the common signal. It should be a process to do.

  In the process of setting the light amount setting value as the second measurement time, when the first measurement time reaches a predetermined time, the light amount setting value indicated by the second measurement time is changed from the maximum light amount setting value to the minimum light amount. The process may be a process of gradually reducing to the set value.

  Alternatively, in the process of setting the light amount setting value as the second measurement time, when the first measurement time reaches a predetermined time, the light amount setting value indicated by the second measurement time is changed from the maximum light amount setting value. It may be a process of instantaneously reducing to the minimum light amount setting value.

  The present invention can provide a 7-segment display device having a configuration capable of appropriately reducing power consumption according to the situation, a light amount control device, and a light amount control method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a 7-segment display device, a light amount control device, and a light amount control method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a light amount control device of a 7-segment display device according to an embodiment of the present invention.

  The light quantity control device for a 7-segment display device according to an embodiment of the present invention includes, for example, a 7-segment display for each digit of the 7-segment display device 2 having 5-digit 7-segment display units 21 to 25 (see FIG. 4). A data signal generating circuit 3 that outputs character data to be displayed on each of the units 21 to 25 as a data signal, and a common that outputs common signals 1 to 5 for controlling the sequential lighting of the 7-segment display units 21 to 25 of each digit A light amount setting register 5 that can set a light amount setting value set as a lighting period indicated by the signal generation circuit 1 and a common signal between a maximum light amount setting value as an initial value and a predetermined minimum light amount setting value; When the duration of the normal operation state of the target device in which the segment display device 2 is arranged or the elapsed time from the end of the last operation is measured and output as the first measurement time The mask command signal for commanding the generation of the mask signal is obtained by subtracting the second measurement time as a value indicating the light amount setting value set according to the first measurement time for each clock period in synchronization with the clock signal. A counter 6 for outputting, and a mask signal generating circuit 7 for generating a mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display units 21 to 25 of each digit according to the mask command signal; The second measurement time is set in the light amount setting register 5 as the light amount setting value according to the first measurement time, and the common signal and the mask signal are combined to generate a combined common signal used as an alternative to the common signal. And a processing unit (CPU) 4.

  FIG. 1 shows a clock signal generation circuit 9 that supplies a clock signal that defines the period of the common signal and the synthesized common signal to the counter 6. The counter 6 supplies a similar clock signal. A clock signal generator may be provided inside.

  When the light quantity control device according to the embodiment of the present invention is regarded as a part of the configuration provided in the 7-segment display device, the 7-segment display device according to the embodiment of the present invention has, for example, a 5-digit display. It can be understood as a 7-segment display device including 7-segment display units 21 to 25 and the light amount control device.

  The seven light-emitting segments constituting the five-digit seven-segment display units 21 to 25 are usually provided with LEDs as light-emitting elements, and are each turned on by causing these LEDs to emit light.

  The data signal generation circuit 3 outputs an 8-bit data signal to supply character data to be displayed to the 5-digit 7-segment display units 21 to 25, respectively. In order to control the sequential lighting of the segment display units 21 to 25, the common signals 1 to 5 having a total of 5 bits are output.

  When the number of digits of the 7-segment display unit is different from the above example, the number of bits of the data signal and the common signal changes according to the number of digits.

  FIG. 2 is a timing chart showing signal waveforms of a clock signal, a mask signal, a common signal, and a composite common signal used in the 7-segment display device and the light amount control device and the light amount control method according to the embodiment of the present invention. is there.

  Although not shown in FIG. 2, a data signal (see FIGS. 4 and 5) as character data indicating the content of information to be displayed on the 5-digit 7-segment display units 21 to 25 is the present invention. The seven-segment display device according to the embodiment and the light amount control device thereof are used, and based on the data signal, each of the seven light-emitting segments that constitute the five-digit seven-segment display units 21 to 25, respectively. Lighting and extinguishing are controlled.

  On the other hand, in FIG. 2, only the common signal 1 among the common signals 1 to 5 for controlling the sequential lighting of the 5-digit 7-segment display units 21 to 25 is shown as a representative. The common signals 1 to 5 are also used in the 7-segment display device and the light amount control device thereof according to one embodiment, and further, the synthesized common signals 1 ′ to 5 generated by synthesizing the common signals 1 to 5 and the mask signal. 'Is used.

  The 7-segment display units 21 to 25 of each digit are configured so that the corresponding common signals 1 to 5 or composite common signals 1 ′ to 5 ′ are turned on during the low level period and are turned off during the high level period. It is configured.

Typical common signal 1 to 5 which is not combined with the mask signal, the scanning period T _C of the 5-digit 7-segment display portions 21 to 25, the lighting period T _D for each digit 7-segment display portions 21 to 25 There is a signal waveform such that 1/5 of _{T C.}

Brightness of lighting of each digit 7-segment display portions 21 to 25, as described above, determined by the length of a lighting period T _D occupying the scanning period T _C. Power consumption in each digit 7-segment display portions 21 to 25 is proportional to the length of a lighting period T _D.

  Therefore, when the operation state of the control device or the like where the 7-segment display device is arranged is continuously normal and stable, or when no operation is performed on the control device or the like, the 7-segment display is performed. When the display content displayed by the device is not particularly focused, the length of the low level period of the common signals 1 to 5 corresponding to the lighting period of the 7-segment display units 21 to 25 of each digit is shortened. The power consumption can be reduced by reducing the lighting brightness of the digit 7-segment display units 21 to 25.

Therefore, in the 7-segment display device and the light amount control device and the light amount control method according to the embodiment of the present invention, the operation state of the control device in which the 7-segment display device is arranged and the presence or absence of an operation are determined, by shortening the length of a lighting period T _D occupying the scanning period T _C of each digit seven segment display portions 21 to 25, within a range that affects the implementation of the grasping and manipulation of the operating state of the control device or the like does not occur A configuration for reducing power consumption in a 7-segment display device is realized.

  Specifically, the continuation time of the normal operation state of the target device in which the 7-segment display device 2 is arranged or the elapsed time from the end of the last operation is measured as the first measurement time, and according to the first measurement time The generation of the mask signal is instructed by subtracting the second measurement time as a value indicating the set light quantity setting value for each clock cycle in synchronization with the clock signal. When the generation of the mask signal is instructed, a mask signal for reducing the length of each lighting period in the scanning period of the 7-segment display units 21 to 25 of each digit is generated accordingly, and the common signal and the mask are generated. The signals are combined with each other to generate a combined common signal, and the 7-segment display units 21 to 25 of each digit are controlled based on the combined common signal.

  With the above control, the 7-segment display device, the light amount control device, and the light amount control method thereof according to the embodiment of the present invention can reduce power consumption in the 7-segment display device.

The mask signal is a signal that may have a high level period that expands and contracts according to the second measurement time in a part of the period corresponding to the low level period of the common signal, and ANDs the mask signal and the common signal. it is thereby possible to generate a composite common signal having a low level period T _S of a length of less than or equal the low level period of the original common signal.

  The control by the 7-segment display device, the light amount control device, and the light amount control method according to the embodiment of the present invention will be described in more detail with reference to the flowchart of FIG.

  FIG. 3 is a flowchart showing the operation of the 7-segment display device and the light amount control device thereof according to the embodiment of the present invention, that is, the procedure of the light amount control method of the 7-segment display device according to the embodiment of the present invention. is there.

  First, it is set whether or not the 7-segment display device according to the embodiment of the present invention and the control by the light amount control device and the light amount control method, that is, the light control of the 7-segment display device is to be executed (step S1). ).

  When carrying out the present invention, the dimming of the 7-segment display units 21 to 25 is performed when the normal operation state of the target device in which the 7-segment display device 2 is arranged continues, and the target device A first measurement time is set in the counter 6 that defines how long the 7-segment display units 21 to 25 are to be dimmed when the last operation ends.

  Here, as an example, it is assumed that the control by the 7-segment display device and the light amount control device and the light amount control method according to the embodiment of the present invention is performed by interrupt processing, and the interrupt processing cycle is 25.6 ms. In the counter 6, a variable A = 35156 + 200 = 35356 is set as the first measurement time. The processing unit (CPU) 4 sets the variable A as counter data in the counter 6 when the target device such as a servo amplifier is turned on, that is, initialized.

  The variable A = 35156 + 200 is an approximate value of a value obtained by dividing 15 minutes (= 900 seconds) + about 5 seconds by an interruption period of 0.0256 seconds. That is, in this embodiment, when the first measurement time is set to 15 minutes and the duration of the normal operation state of the target device or the elapsed time from the end of the last operation reaches 15 minutes, the 7-segment display unit 21 The dimming is performed to gradually reduce the lighting brightness of 25 to 25 in about 5 seconds.

  On the other hand, the processing device (CPU) 4 sets the variable B that defines the lighting brightness, that is, the light amount of the 7-segment display units 21 to 25 in the light amount setting register 5 as the second measurement time. The variable B is read from the light amount setting register 5 into the counter 6 and, as will be described below, as a second measurement time that defines the period from the start of each cycle of the clock signal to the start of the high level period of the mask signal. The time when the clock signal is subtracted from the start time of each cycle to 0 (zero) for each cycle of the clock signal is determined as the start time of the high level period of the mask signal in each cycle of the clock signal.

  Here, the initial value of variable B is set to variable B = 50. The initial value 50 of the variable B set as the second measurement time is set as a value corresponding to one period of the clock signal used in the 7-segment display device and the light amount control device according to the embodiment of the present invention. .

  The low level period of each common signal corresponding to the lighting period of the 7-segment display units 21 to 25 of each digit corresponds to one cycle of the clock signal. The variable B set as the second measurement time defines the time from the start time of each cycle of the clock signal to the start time of the high level period of the mask signal.

Therefore, when the variable B set as the second measurement time is the initial value 50 corresponding to one period of the clock signal, the high level period of the mask signal does not occur, and the mask signal is low throughout the entire period. since a level, even if aND combining the respective common signal and the mask signal, the length of the low period T _S of the synthetic common signals 1 'to 5' is generated, one to each of the original common signal 5, even if the 7-segment display units 21 to 25 of each digit are controlled by using the composite common signals 1 ′ to 5 ′, the 7-segment display unit 21 of each digit remains unchanged. The lighting period from 1 to 25 is not shortened. That is, the initial value 50 of the variable B set as the second measurement time is the maximum light amount setting value of the 7 segment display units 21 to 25 of each digit.

  When the first measurement time (variable A) is set for the counter 6 by the processing device (CPU) 4, the processing device (CPU) 4 monitors the presence or absence of an operation such as key input of the target device (step S3). If there is an operation such as key input of the target device, the first measurement time (variable A) of the counter 6 is reset to the initial value of variable A = 35156 + 200 (step S4).

  Further, the processing device (CPU) 4 monitors whether or not the normal operation state of the target device continues, that is, whether or not an abnormal operation has occurred (step S5), and detects the occurrence of abnormal operation of the target device. If detected, the first measurement time (variable A) of the counter 6 is reset to the initial value of variable A = 35156 + 200 (step S6).

  The monitoring of the abnormal operation occurrence of the target device is performed by the processing unit (CPU) 4 always interrupting the alarm table that manages whether or not an alarm (alarm) that is activated in response to the occurrence of various abnormal operations of the target device is interrupted. This is done by monitoring every processing cycle. The alarm table may be configured by hardware or software.

  If there is no operation such as key input of the target device or occurrence of abnormal operation, the processing device (CPU) 4 determines whether or not the inequality A> 200 holds for the current variable A of the counter 6. Identify (step S7).

  If the inequality A> 200 holds, it means that the elapsed time from the end of the last operation of the target device or the duration of the normal operation state has not reached 15 minutes set as the first measurement time. The device (CPU) 4 maintains the variable B as the second measurement time set in the light amount setting register 5 as the light amount setting value at the initial value 50 that is the maximum light amount setting value (step S8). In this case, since there is no operation such as key input of the target device and the normal operation state of the target device continues, the variable A set as the first measurement time in the counter 6 is changed to the variable A. A is decremented by 1 as A = A-1 (step S9).

  The variable A as the first measurement time and the variable B as the second measurement time maintained or changed in the above steps are respectively held in the counter 6 and the light amount setting register 5 (step S13), the second time In order to shift to the subsequent cycle, the process returns to step S3.

  The counter 6 reads the variable B held in the light amount setting register 5 as the second measurement time, and subtracts the second measurement time from the start time of each cycle for each cycle of the clock signal to become 0 (zero). This time is determined as the start time of the high level period of the mask signal in each cycle of the clock signal, and the mask command signal is output to the mask signal generation circuit 7. However, here, the variable B as the second measurement time is set to the initial value 50, which is the maximum light amount setting value, and the mask command signal is output at the end of each cycle of the clock signal. The high level period of the mask signal does not occur, and remains at the low level over the entire period of each cycle. Even if this mask signal and each of the common signals 1 to 5 are AND-combined, each combined common signal 1 The signal waveforms of “to 5” do not change as the original signal waveforms of the common signals 1 to 5.

  On the other hand, if the inequality A> 200 is not satisfied in step S7, the elapsed time from the end of the last operation of the target device or the continuation time of the normal operation state has already passed 15 minutes, This means that it has already entered the period of about 5 seconds for dimming to gradually reduce the lighting brightness of the 7-segment display units 21 to 25, so that the processing unit (CPU) 4 further includes a counter Whether the inequality A ≧ 40 holds for the current variable A of 6 is identified (step S7). That is, it is identified whether or not the elapsed time is about 4 seconds or less in the period of about 5 seconds for dimming that gradually reduces the lighting brightness of the 7-segment display units 21 to 25. Regarding the elapsed time, the reason why such second unit identification is performed is that, in the present embodiment, the 7-segment display unit 21 in the first about 4 seconds in the period of about 5 seconds after the 15 minutes have elapsed. This is because dimming is performed to gradually reduce the brightness of lighting of 25 to 25 in inverse proportion to the elapsed time.

  Therefore, when the inequality A ≧ 40 holds, the processing device (CPU) 4 sets the variable B as the second measurement time set in the light amount setting register 5 as the light amount setting value to the variable B = A / 4. . Since the variable A set as the first measurement time is a value that decreases with the passage of time, the variable B also decreases with the passage of time, and the first of the period of about 5 seconds after the lapse of 15 minutes. For about 4 seconds, dimming is performed in which the lighting brightness of the 7-segment display units 21 to 25 gradually decreases in inverse proportion to the elapsed time. In this case, since there is no operation such as key input of the target device and the normal operation state of the target device continues, the variable A set as the first measurement time in the counter 6 is changed to the variable A. A is decremented by 1 as A = A-1 (step S9).

  The variable A as the first measurement time and the variable B as the second measurement time maintained or changed in the above steps are respectively held in the counter 6 and the light amount setting register 5 (step S13), the second time In order to shift to the subsequent cycle, the process returns to step S3.

The counter 6 reads the variable B held in the light amount setting register 5 as the second measurement time, and subtracts the second measurement time from the start time of each cycle for each cycle of the clock signal to become 0 (zero). This time is determined as the start time of the high level period of the mask signal in each cycle of the clock signal, and the mask command signal is output to the mask signal generation circuit 7. Here, since the variable B as the second measurement time is set to B = A / 4 and 40 ≦ A ≦ 200, 10 ≦ B ≦ 50. Therefore, since the mask command signal is output at the time when 1/5 period or more and 5/5 period or less has elapsed from the start time of each period of the clock signal, the mask signal is as shown in FIG. The high level period starts from that point to the end of each cycle. When the AND mask signal and the common signal 1 to 5 synthesis, for a period corresponding to the high-level period of the mask signal has a low level period T _S is shortened signal waveform from each of the common signals 1 to 5 original Each composite common signal 1 'to 5' is generated.

When the sequential lighting of the five-digit 7-segment display units 21 to 25 of the 7-segment display device 2 is controlled using the combined common signals 1 ′ to 5 ′, the low-level period T _S than the original common signals 1 to 5 is controlled. Accordingly, the brightness of lighting of the 7-segment display portions 21 to 25 of each digit is reduced by the amount of shortening.

  On the other hand, if the inequality A ≧ 40 is not satisfied in step S10, about 4 seconds out of a period of about 5 seconds for dimming to gradually reduce the lighting brightness of the 7-segment display units 21 to 25. Means that it has already entered the last approximately one second period, so that the processing unit (CPU) 4 sets the variable B as the second measurement time set in the light amount setting register 5 as the light amount setting value. Variable B = 10. This value is the minimum light amount setting value of the variable B as the second measurement time set in the light amount setting register 5 as the light amount setting value in the present embodiment.

  The variable A as the first measurement time and the variable B as the second measurement time maintained or changed in the above steps are respectively held in the counter 6 and the light amount setting register 5 (step S13), the second time In order to shift to the subsequent cycle, the process returns to step S3.

The counter 6 reads the variable B held in the light amount setting register 5 as the second measurement time, and subtracts the second measurement time from the start time of each cycle for each cycle of the clock signal to become 0 (zero). This time is determined as the start time of the high level period of the mask signal in each cycle of the clock signal, and the mask command signal is output to the mask signal generation circuit 7. Here, since the variable B as the second measurement time is set to B = 10 which is the minimum light amount setting value, the mask command signal is output by 1/5 from the start time of each cycle of the clock signal. As shown in FIG. 2, the mask signal is in a high level period from that point to the end point of each cycle. When the AND mask signal and the common signal 1 to 5 synthesis, for a period corresponding to the high-level period of the mask signal has a low level period T _S is shortened signal waveform from each of the common signals 1 to 5 original Each composite common signal 1 'to 5' is generated. In this case, the low level period T _S of the synthetic common signals 1 'to 5' is a period until the time of lapse of 1/5 period from the start of each period of the clock signal.

  Therefore, when the variable B as the second measurement time is set to 10 which is the minimum light amount setting value, the lighting brightness of the 7-segment display units 21 to 25 of each digit is 1/5 of the initial value, that is, the maximum value. Reduced to

  In the second and subsequent cycles, steps S3 to S13 are repeated in the same manner as described above.

  As a result of performing the control as described above, the 7-segment display device, the light amount control device, and the light amount control method according to the embodiment of the present invention are the operations of the target device such as a control device in which the 7-segment display device is disposed The power consumption of the 7-segment display device can be reduced within a range that does not hinder the grasp of the state and the execution of the operation.

  In the embodiment described above, when the duration time of the normal operation state of the target device or the elapsed time from the end of the last operation reaches 15 minutes, the brightness of the 7-segment display units 21 to 25 is lit. Although dimming is performed to gradually reduce the brightness in about 5 seconds, the lighting brightness of the 7-segment display portions 21 to 25 may be instantaneously reduced instead of gradually reducing. In this case, when the variable A set as the first measurement time is subtracted to 0 (zero), the variable B set as the second measurement time is switched from the maximum light amount setting value to the minimum light amount setting value. It is good to do so.

It is a block diagram which shows the structure of the light quantity control apparatus of the 7 segment display apparatus which concerns on this invention. FIG. 2 is a timing chart showing signal waveforms of a clock signal, a mask signal, a common signal, and a composite common signal used in the 7-segment display device and the light amount control device thereof according to the embodiment of the present invention. It is a flowchart which shows the procedure of the light quantity control method of the 7 segment display apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows schematic structure of a 7 segment display apparatus and its control apparatus. It is a timing chart which shows each signal waveform of a data signal and a common signal used in a 7 segment display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Common signal generation circuit 2 7 segment display apparatus 3 Data signal generation circuit 4 Processing apparatus (CPU)
5 Light quantity setting register 6 Counter 7 Mask signal generation circuit 9 Clock signal generation circuit 21, 22, 23, 24, 25 7 segment display section

Claims (28)

A multi-digit 7-segment display,
A data signal generating circuit for outputting character data to be displayed on the 7-segment display section of each digit as a data signal;
A common signal generating circuit for outputting a common signal for controlling the sequential lighting of the 7-segment display portion of each digit;
A light amount setting register that can set a light amount setting value set as a lighting period indicated by the common signal between a maximum light amount setting value as an initial value and a predetermined minimum light amount setting value;
The continuation time of the normal operation state of the arranged target device or the elapsed time from the end of the last operation is measured and output as the first measurement time, and the light amount setting value set according to the first measurement time A counter that outputs a mask command signal for commanding generation of a mask signal by subtracting the second measurement time as a value indicating the value for each clock period in synchronization with the clock signal;
A mask signal generating circuit for generating the mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display portion of each digit in response to the mask command signal;
The second measurement time is set in the light amount setting register as the light amount setting value according to the first measurement time, and the common signal and the mask signal are combined to be used as an alternative to the common signal. A processing device for generating a common signal;
A 7-segment display device comprising:   The 7-segment display device according to claim 1, wherein the first level period of the common signal defines a lighting period of the 7-segment display unit.   The mask signal is a signal that may have a second level period that expands and contracts according to the second measurement time in a part of a period corresponding to the first level period of the common signal. Item 7. A 7-segment display device according to item 2.   The processing device AND-combines the common signal and the mask signal to generate the combined common signal having a first level period having a length equal to or shorter than the first level period of the common signal. The 7-segment display device according to claim 3.   When the first measurement time reaches a predetermined time, the processing device gradually reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. The 7-segment display device according to any one of claims 1 to 4.   When the first measurement time reaches a predetermined time, the processing device instantaneously reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. The 7-segment display device according to any one of claims 1 to 4.   The duration of the normal operation state of the target device is measured by the processing device monitoring an alarm table that manages the presence or absence of an alarm that is activated in response to the occurrence of various abnormal operations of the target device. The 7-segment display device according to any one of claims 1 to 6.   The 7-segment display device according to claim 7, wherein the alarm table is configured by software.   The 7-segment display device according to claim 7, wherein the alarm table is configured by hardware.   10. The 7-segment display device according to claim 1, further comprising a clock signal generation circuit that supplies the clock signal that defines a cycle of the common signal and the combined common signal.   10. The counter according to claim 1, wherein the counter includes a clock signal generator that supplies the clock signal that defines a cycle of the common signal and the combined common signal. Segment display device. A data signal generating circuit for outputting, as a data signal, character data to be displayed on the 7-segment display unit of each digit of a 7-segment display device having a multi-digit 7-segment display unit;
A common signal generating circuit for outputting a common signal for controlling the sequential lighting of the 7-segment display portion of each digit;
A light amount setting register that can set a light amount setting value set as a lighting period indicated by the common signal between a maximum light amount setting value as an initial value and a predetermined minimum light amount setting value;
The continuation time of the normal operation state of the arranged target device or the elapsed time from the end of the last operation is measured and output as the first measurement time, and the light amount setting value set according to the first measurement time A counter that outputs a mask command signal for commanding generation of a mask signal by subtracting the second measurement time as a value indicating the value for each clock period in synchronization with the clock signal;
A mask signal generating circuit for generating the mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display portion of each digit in response to the mask command signal;
The second measurement time is set in the light amount setting register as the light amount setting value according to the first measurement time, and the common signal and the mask signal are combined to be used as an alternative to the common signal. A processing device for generating a common signal;
A light amount control device for a 7-segment display device.   The light quantity control device for a seven-segment display device according to claim 12, wherein the first level period of the common signal defines a lighting period of the seven-segment display unit.   The mask signal is a signal that may have a second level period that expands and contracts according to the second measurement time in a part of a period corresponding to the first level period of the common signal. Item 14. A light quantity control device for a seven-segment display device according to Item 13.   The processing device AND-combines the common signal and the mask signal to generate the combined common signal having a first level period having a length equal to or shorter than the first level period of the common signal. The light quantity control device for a seven-segment display device according to claim 14.   When the first measurement time reaches a predetermined time, the processing device gradually reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. The light quantity control device for a seven-segment display device according to any one of claims 12 to 15.   When the first measurement time reaches a predetermined time, the processing device instantaneously reduces the light amount setting value indicated by the second measurement time from the maximum light amount setting value to the minimum light amount setting value. The light quantity control device for a seven-segment display device according to any one of claims 12 to 15.   The duration of the normal operation state of the target device is measured by the processing device monitoring an alarm table that manages the presence or absence of an alarm that is activated in response to the occurrence of various abnormal operations of the target device. The light quantity control device for a seven-segment display device according to any one of claims 12 to 17.   The light amount control device for a seven-segment display device according to claim 18, wherein the alarm table is configured by software.   19. The light quantity control device for a seven-segment display device according to claim 18, wherein the alarm table is configured by hardware.   21. The light quantity of the 7-segment display device according to claim 12, further comprising a clock signal generation circuit that supplies the clock signal that defines a cycle of the common signal and the composite common signal. Control device.   21. The counter according to claim 12, wherein the counter includes a clock signal generator that supplies the clock signal that defines a cycle of the common signal and the combined common signal. Light control device for segment display device. The maximum light quantity as an initial value is the light quantity setting value set as the lighting period indicated by the common signal for controlling the sequential lighting of the 7-segment display section of each digit of the 7-segment display device having a multi-segment 7-segment display section The process of setting to the set value,
A process of measuring, as the first measurement time, the duration of the normal operation state of the target device in which the 7-segment display device is arranged or the elapsed time from the end of the last operation;
A step of setting the light amount setting value as a second measurement time as a value indicating the light amount setting value between the maximum light amount setting value and a predetermined minimum light amount setting value according to the first measurement time;
Generate a mask signal for shortening the length of each lighting period in the scanning period of the 7-segment display of each digit by subtracting the second measurement time for each clock period in synchronization with the clock signal The process of
Combining the common signal and the mask signal to generate a combined common signal used as an alternative to the common signal;
A method for controlling the amount of light in a 7-segment display device.   The light amount control method for a 7-segment display device according to claim 23, wherein the first level period of the common signal defines a lighting period of the 7-segment display unit.   The mask signal is a signal that may have a second level period that expands and contracts according to the second measurement time in a part of a period corresponding to the first level period of the common signal. Item 25. A light amount control method for a seven-segment display device according to Item 24.   In the process of generating the composite common signal, the common signal and the mask signal are AND-combined to generate the composite common signal having a first level period that is less than or equal to the first level period of the common signal. 26. The light quantity control method for a seven-segment display device according to claim 25, wherein   In the process of setting the light amount setting value as the second measurement time, when the first measurement time reaches a predetermined time, the light amount setting value indicated by the second measurement time is changed from the maximum light amount setting value to the minimum light amount. 27. The light amount control method for a 7-segment display device according to claim 23, wherein the light amount control method is a process of gradually reducing the set value to a set value.   In the process of setting the light amount setting value as the second measurement time, when the first measurement time reaches a predetermined time, the light amount setting value indicated by the second measurement time is changed from the maximum light amount setting value to the minimum light amount. 27. The light quantity control method for a seven-segment display device according to claim 23, wherein the light quantity control method is a process of instantaneously reducing the set value to a set value.

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