JPH01271809A - Input abnormality detector for control pulse signal - Google Patents

Abstract

PURPOSE:To detect the input abnormality of a control pulse signal with high accuracy by forming a blind sector in accordance with a reference speed level and at the same time setting a delay time for detection of the abnormality in accordance with the reference speed level. CONSTITUTION:The reference speed level '1' is supplied to a blind sector arithmetic circuit 16 for calculation of a blind sector having its upper and lower limit levels. At the same time, a mask time arithmetic circuit 22 calculates a large mask time T1 against a low reference speed level and a small mask time T1 against a high reference speed level respectively in accordance with the level '1'. These mask times are applied to a mask detector 12. While a blind sector detector 18 checks the presence or absence of a difference signal 7 received from an input pulse number change component detector 6. If the difference value is included in a blind sector, the detector 18 transmits a normal detecting signal 19. The other normal detecting signal 15 is obtained when the input pulse number, i.e., the feedback value is equal to zero and at the same time the level '1' is not equal to zero. When these two conditions are satisfied, an AND circuit 20 transmits a normal detecting signal 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to a control system that controls a device to be controlled by a control pulse signal input from a pulse oscillator, in which there is an abnormality in the input of the control pulse signal. The present invention relates to a control pulse signal input abnormality detection device that detects this.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional control pulse signal input abnormality detection device. The abnormality is detected by detecting that the number of pulses of the control pulse signal does not change. In the figure, 1 is the speed reference value output to the controlled device, 2 is the speed reference value key 0 detector that detects that the speed reference value 1 is not zero, 3 is its detection signal, and 4 is the controlled object The current value of the input pulse number count value that indicates the count value of the number of pulses of the control pulse signal input to the device in the current cycle, 5 is the count of the number of pulses of the control pulse signal input to the controlled device in the previous cycle 6 is a detector that detects the change in the number of input pulses from the difference between the current value 4 and the previous value 5; 7 is a signal indicating the value of the difference; 8 1 is a detector that detects that the signal 7 indicating the difference value is zero, that is, the number of input pulses minus 0; 9 is its detection signal; 10 is an AND circuit to which detection signals 3 and 9 are added; 11 is its output signal; 12 1 is a mask detector that checks the output signal 110 level after a predetermined mask time T1 after the output signal 11 of a predetermined level is applied; 13 is an abnormality detection signal; 14 is an inverter for inverting the abnormality detection signal; 15 is an inverter 14 This is the normal detection signal obtained from.

Next, the operation will be explained.

When the speed reference value 1 given to the controlled device is not zero, the detector 2 outputs a detection signal 3. At this time, if the signal 7 indicating the difference between the current value 4 and the previous value 5 output from the detector 6 indicates zero, the detector 8 outputs a detection signal 9. At this time, the AND circuit 10 outputs, for example, an H level (high level) output signal 11 indicating a contradiction that the number of input pulses, which is the feedback value, is zero even though the speed reference value 1 is not zero. . However, in this case, the number of input pulses may be zero even under normal conditions due to reasons such as response delay of the controlled device or the width of the pulse increment at low speeds.
In the mask detector 12, the output signal 1 is detected at a time point delayed by a predetermined mask time T1 from the rise of the output signal 11.
Check the level of 1. That is, as shown in FIG. 4, if the output signal 11 continues to be at the H level after a predetermined mask time T1, it is regarded as abnormal, and the abnormality detection signal 13 is output. This abnormality detection signal 13 is inverted by an inverter 14 and becomes a normal detection signal.

[Problem to be solved by the invention]

Since the conventional control pulse signal input abnormality detection device is configured as described above, it detects an abnormality only when the number of input pulses serving as the feedback value becomes zero when the speed reference value 1 is not zero. Moreover, since the mask time T1 given to the mask detector 12 is constant, it is not possible to deal with speed reference values 1 of various sizes, and abnormality detection is delayed especially in the case of a high speed reference value. There were problems such as:

This invention was made in order to solve the above-mentioned problems, and it is possible to detect abnormalities even when the number of input pulses is other than zero, and to take prompt action according to various speed reference values indicated on the controlled equipment. The present invention aims to provide a control pulse signal input abnormality detection device that can perform accurate detection.

[Means to solve the problem]

The control pulse signal input abnormality detection device according to the present invention includes:
A dead zone is set in the control system according to the speed reference value, and the mask time is made variable, so that when the change in the number of input pulses is within the dead zone, it is considered normal.

[For production]

The control pulse signal input abnormality detection device of the present invention performs abnormality detection while constantly checking the correlation between the speed reference value and the number of input pulses, and also performs immediate abnormality detection according to the speed reference value. be exposed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 to 15 are the same as the same reference numerals in FIG. 3, so their explanation will be omitted. However, the mask time Tl given to the mask detector 12 is variable by a mask time calculation circuit 22, which will be described later. In Figure 1, 16
is a dead zone calculation circuit, which calculates a dead zone centered around the given speed reference value 1. 17 is a signal indicating the dead zone, and 18 is a signal 7 indicating the difference between the current value 4 and the previous value 5 obtained from the detector 6 and the signal 17 indicating the dead zone, and the difference value is determined to be in the dead zone. 19 is a normal detection signal that is output when the difference value is within the dead band; 20 is a logical product in which the normal detection signal 19 and the above-mentioned normal detection signal 15 are added; circuit, 21 is a true normal detection signal output from the AND circuit 20, -2
Reference numeral 2 denotes a mask time calculation circuit that calculates a mask time T1 having a length corresponding to the given speed reference value 1.

Next, the operation will be explained.

A speed reference value 1 given to a controlled device provided with a pulse oscillator is input to the dead zone calculation circuit 16 . This speed reference value 1 is converted to the number of pulses of the control pulse signal, and the positive and negative margins are added to the converted value, so that υ
, a dead zone having a lower limit value and an upper limit value is calculated. At the same time, according to the speed reference value 1, the mask time calculation circuit 22 calculates a long mask time T1 for the low speed reference value, and a short mask time T1 for the high speed reference value.
is calculated and added to the mask detector 12. Therefore, the second
As shown in the figure, since the mask time T1 changes depending on the speed, an abnormality detection signal may be generated even though it is normal due to the response delay of the controlled device or the increment width of the pulse at low speeds. 13 can be prevented from being output.

On the other hand, the dead zone detector 18 checks whether the signal 7 indicating the difference value from the detector 6 is within the dead zone, and outputs a normal detection signal 19 if the difference value is within the dead zone. The other normality detection signal 15 is obtained when the number of input pulses, which is the feedback value, becomes zero when the speed reference value 1 is not zero. Therefore, the AND circuit 20 outputs the true normal detection signal 21 when these two conditions are obtained.
Output.

In the above embodiment, two normal detection signals 19°15
is added to the AND circuit 20, however, the abnormality detection signal may be obtained by adding a signal obtained by inverting the normality detection signal 19 and the abnormality detection signal 13 to the OR circuit. Further, the detector 6 calculates the difference between the current value 4 and the previous value 5, but this detector 6 may be of any type as long as it can count control pulse signals within a fixed period.

〔Effect of the invention〕

As described above, according to the present invention, a dead zone of a size corresponding to the speed reference value is provided, and a delay time (mask time) for abnormality detection is provided depending on the speed reference value. Detection is performed while checking the correlation between the reference value and the number of input pulses, and abnormality detection can be performed even when the number of input pulses is other than zero. Furthermore, when the number of input pulses becomes zero, Since the detection is performed with a quick response, there is an effect that the detection can be performed with high precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control pulse signal input abnormality detection device according to an embodiment of the present invention, FIG. 2 is a time chart regarding mask detection in the same device, and FIG. 3 is a conventional control pulse signal input abnormality detection device. A block diagram showing the apparatus, and FIG. 4 is a time chart regarding mask detection of the apparatus. 1 is a speed reference value, 2 is a detector for a speed reference value of 4o, 6 is a detector for a change in the number of input pulses, 8 is a detector for an input pulse number of 20, 12 is a mask detector, 16 is a dead zone calculation circuit, 1
8 is a dead zone detector, and 22 is a mask time calculation circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Corporation

Claims (1)

[Claims] A dead zone calculation circuit that calculates a dead zone of a size corresponding to a speed reference value given to a controlled device controlled by a control pulse signal, and a detector that detects a change in the number of input pulses of the control pulse signal in a predetermined period. and a dead zone detector that compares the change in the input pulse with the dead zone, and detects after a predetermined mask time that the speed reference value is given and there is no change in the number of input pulses. An input abnormality detection device for control pulse notes, comprising a mask detector and a mask time calculation circuit that calculates the mask time according to the speed reference value.