JPS6249431A - Signal stabilizing device - Google Patents

Abstract

PURPOSE:To prevent the sudden change of a signal by eliminating a noise component, and also to inform the abnormality of an input signal by providing a noise deciding device for deciding a noise, based on a noise level set to a level switch, and a noise counter for outputting an input abnormal alarm signal or an input abnormal reset signal. CONSTITUTION:When the value of a digital which is inputted through a signal line (b) is out of the range of a value set to a level switch 2, a noise deciding device 3 stops the output of a signal line (c), and also outputs an abnormal signal to a signal line (e). When a signal line (d) from which a normal signal is outputted is connected to a retrigger terminal, and the abnormal signal is inputted by connecting the signal line (e) being the abnormal signal to a count start terminal, a noise counter 4 executes count-up until it reaches the time set in advance. At the time when it reaches the time, an input abnormal alarm signal is outputted to a signal line (g), but when the normal signal is outputted to a signal line (d) on the way of count-up, the count is reset to zero. In this way, as long as the abnormal signal is not continued exceeding the time set in advance, no input abnormal alarm signal is outputted to the signal line (g).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conversion device that converts an analog input signal into a digital signal, such as a digital temperature control device. This makes it possible to stabilize the system and also to notify of input abnormalities.

[Conventional technology]

Conventional 1. As shown in FIG. 2, this type of conversion device sends a signal to a CPU 9 (microcomputer), which is a processing device, through a ψ converter 1 that simply converts an analog signal into a digital signal.

[Problem that the invention seeks to solve]

However, in the conventional method described above, noise components naturally included in the input signal are converted into digital signals and sent to the CPU, so there is a possibility of malfunction, and the signal may suddenly change due to the noise components. When this happens, for example, the display suddenly changes and flickers, making it very difficult to read, which can cause problems, and even when it is expected that an abnormality has occurred in the input, such as when such a state lasts for a certain period of time. The above problem of not having a means of notification can be handled by the CPU, which is a processing device, but even if the complexity of creating a program to be executed by the CPH can be tolerated. , a considerable part of cpty's processing capacity is used for this processing, causing the problem that the original processing cannot be performed (i.e., insufficient capacity), and the execution speed is slow due to sequential execution processing, which is a characteristic of the CPU. This caused other problems, such as delays.

[Means for solving problems]

As specific means for solving the above-mentioned conventional problems, the present invention provides a converter for converting an analog input signal into a digital signal, a level switch for setting a noise bell, and a level switch for setting a noise bell. a noise determiner that makes a determination based on a noise level set in a switch; a noise counter that measures the duration that the noise determiner determines as noise and outputs an input abnormality alarm signal or an input abnormality recovery signal; a data determiner that compares the previous retained data value with the current data value; a data adder that increments the retained data value based on the result of the data determiner; and a data subtracter that decrements the retained data value; and a data subtracter that retains the retained data value. By providing a signal stabilizing device characterized by having a data holder that simultaneously removes noise components and prevents sudden changes in the signal, it is possible to solve the above-mentioned problems, and also to prevent abnormalities in the input signal. This makes it possible to notify the public.

〔Example〕

Next, the present invention will be explained in detail based on an embodiment shown in the drawings. In order to facilitate understanding, the same parts as in the conventional example will be described with the same reference numerals.

The reference numeral 1 in FIG. 1 is a ψ converter similar to the conventional example, which converts the analog signal from the signal line a into a digital signal and outputs it to the signal line A.

As explained in the conventional example, the analog signal from the signal line a naturally includes a noise component, and this noise component is converted into a digital signal outputted to the signal line through the Ayu converter 1. It will also be included in the signal.

However, in almost all cases, such as when the analog signal is a thermistor output for temperature measurement, it is possible to set the normal range of the output value, and when an output outside that range occurs, it is possible to set the output value as a noise component. It is possible to determine that. A particularly extreme example is given in the case of the thermistor output described above. When the thermistor circuit is disconnected or short-circuited, the output outside the normal range continues.

The level switch 2 is used to set the above-mentioned normal range. For example, by using a digital switch, it is possible to set the upper limit value, the lower limit value, or both as digital values. The noise determiner 3, which is obtained by using, for example, a digital comparator, operates according to the value set in the level switch 2, and its operation is based on the value of the digital signal inputted through the signal line to the level switch 2. If it is within the set value range, the digital signal of the signal line S is passed through as is and outputted to the signal line C, and a normal signal is outputted to the signal line d.If it is outside the range, the digital signal of the signal line C is output. At the same time, an abnormal signal is output to the signal line θ.

For example, in the noise counter 4 obtained using a retrigger timer, the signal line d, which outputs the above-mentioned normal signal, is connected to the retrigger terminal, and the abnormal signal is input by connecting the signal line e, which is the abnormal signal, to the count start terminal. Then, the noise counter 4 counts up until it reaches a preset time, and when it reaches the time, it outputs an input abnormality alarm signal to the signal line g. Since the count is reset to zero when the signal is output to the signal line g, no input abnormality alarm signal is output to the signal line g unless the abnormality signal continues for a period longer than a preset time in the noise counter 4. Incidentally, the input abnormality recovery signal is output to the signal line g when there is no signal output to the signal line g.

For example, a data determiner 5 obtained using a digital comparator inputs an input signal inputted through a signal line C converted into a digital value by the A/D converter 1 via the noise determiner 3 and a data holder 6. Compare the held data up to the previous time, and if both signals are the same, output to signal line j, and if input signal > held data, signal edge k
When the input signal is held data, it is output to the signal line t. At the same time, the data determiner 5 includes the noise determiner 3.
A signal line f branched from the signal line e that outputs the abnormal signal is input, and if there is an output on the signal line f, the comparison function is stopped. As a result, the data determiner 5 when the noise determiner 3, which has no output on the signal line C, determines that it is abnormal.
This prevents abnormal data from being compared.

For example, the data holder 6 obtained using a register has an input/output function and a storage function, and the data adder 7, which also uses a register etc., has an input/output function and an increment function (adds 1 to the contents of the register). The data subtractor 8 obtained in the same manner has an input/output function and a decrement function (subtracts 1 from the contents of the register), and mutually exchanges contents, thereby resulting in the above-mentioned data. When the comparison by the determiner 5 is input signal>held data, 1 is added to the contents of the data holder 6 in one operation, and in the opposite case, 1 is subtracted from the contents of the data holder 6,
If they are the same, the contents of the data holder 6 are output to the CPU 9 via the signal line p without being changed.

Note that the signal lines m and n are the data holder 6, the data adder 6, the data adder 7, and the data subtracter 8 are implemented by a single register that has input/output functions and increment and decrement functions. things are possible.

〔Effect of the invention〕

As explained above, by providing a level switch that sets the noise level and a noise judger that makes a judgment based on the noise level set to the level switch, signals outside the set range are only detected by signals within the range. It is possible to process and obtain accurate results. In addition, the setting values are flexible and highly practical. By installing a noise counter, an input abnormality alarm signal is generated when a signal outside the set range continues for a certain period of time, and a function is added to notify abnormalities such as disconnection or short circuit of the input device. When the abnormality is recovered, the operation can be resumed immediately using the input abnormality recovery signal and the previous data stored in the data holder. Furthermore, by combining a data determiner, data adder, data subtracter, and data holder, data increases or decreases by one unit in one operation, which prevents sudden data changes and noise caused by surge voltage, etc. It has an extremely high practical effect in compressing components, and by freeing the CPU, which is the processing device, from these processes, it also has the effect of enabling even faster processing and expansion of functions. It is played together.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a signal stabilizing device according to the present invention, and FIG. 2 is a block diagram showing a conventional example. 1... ψ converter 2... Level switch 3... Noise judger 4...
Noise counter 5... Data judger 6...
...Data holder 7...Data adder
8... Data subtractor 9... CP
U a -p...Signal line patent applicant Stanley Electric Co., Ltd. Procedural amendment dated November 5, 1985

Claims (1)

[Claims] An A/D converter that converts an analog input signal to a digital signal, a level switch that sets the noise level,
A noise determiner that makes a determination based on the noise level set in the level switch, and a noise counter that measures the duration that the noise determiner determines as noise and outputs an input abnormality alarm signal or an input abnormality recovery signal. a data determiner that compares the previous retained data value with the current data value, a data adder that increments the retained data value based on the result of the data determiner, a data subtracter that decrements the retained data value, and a data subtracter that decrements the retained data value. A signal stabilizing device comprising: a data holder that holds and outputs data.