JPH0526764A - Abnormality detector of optical transmission system - Google Patents

Abstract

PURPOSE:To simply detect the abnormality of the quantity of light due to the disconnection of an optical fiber by transmitting a reference signal consisting of a discrimination pulse and a duty pulse and detecting the magnitude of the pulse width outputted from a counter. CONSTITUTION:A reference signal A consisting of a discrimination pulse Al and a duty pulse A2 is transmitted from a reference signal generation means 11 and gates G1, G2 are opened by a high frequency pulse C only when the duty pulse A2 is H or L to input a gate pulse D1 or D2 to a counter 15. The counter 15 counts up the gate pulse D1 at the time of H and counts down the gate pulse D2 at the time of L. Since the width of the pulse outputted from the counter 15 becomes small when the quantity of light is abnormally reduced and becomes large when the quantity of light is abnormally increased, the abnormality of the quantity of light is simply detected through a host CPU 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for an optical transmission system, and more particularly to means for easily detecting an abnormality in the amount of light due to a broken optical fiber or the like.

[0002]

2. Description of the Related Art An optical transmission system, which is widely used as a control system for industrial robots, converts an electric signal from a transmitting side into an optical signal and transmits the optical signal from an optical fiber to a receiving side. It is designed to be converted back into an electric signal at.

In this kind of optical transmission system, if the optical fiber is broken, the light quantity becomes abnormal. Therefore, an inspection is performed to detect the presence or absence of the light quantity abnormality. As this inspection means, conventionally, for example, means for detecting the amount of light when online using an optical power tester, or an electric circuit capable of outputting the received light amount as an analog signal to the receiving side is added, and the quality of the light amount is determined by the output value It is known how to judge.

[0004]

However, the former method has a problem that it requires manpower for checking the light quantity and that the light quantity can be checked only online. The latter method requires a special opto-electrical converter that can output the light quantity as an analog value, or an A / D converter for digital processing, which complicates the apparatus and increases the cost. There was a problem that became.

Therefore, the present invention provides, by simple means,
It is an object of the present invention to provide means capable of detecting an abnormality in an optical transmission device.

[0006]

To this end, the present invention provides a reference signal generating means for generating a reference identification signal composed of an identification pulse and a duty pulse, and an identification pulse for receiving the reference signal and detecting the identification pulse. Detection means, high-frequency clock pulse generation means for generating a high-frequency clock pulse, and a gate that opens only when the duty pulse is H or L to pass the clock pulse oscillated from the high-frequency clock pulse generation means. A gate, a second gate that opens only when the duty pulse is L or H, and passes a clock pulse oscillated from the high-frequency clock pulse generator, and inputs from the first gate and the second gate An abnormality detection device for the optical transmission device is configured by a counter that adds the generated clock pulses.

[0007]

According to the above construction, the presence or absence of abnormality can be easily detected by the magnitude of the pulse width output from the counter.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 2 is a system diagram of an optical transmission device. A transmitting unit 1 for converting an input electric signal into an optical signal and a receiving unit 2 for converting an optical signal transmitted from the transmitting unit 1 into an electric signal. And an optical fiber 3 for transmitting an optical signal from the transmitter 1 to the receiver 2.

FIG. 1 shows the configuration of the electric circuit of the receiving section 2. Reference numeral 11 is a reference signal generating means for transmitting the reference signal A shown in FIG. The reference signal A is composed of an identification pulse A1 for distinguishing it from other signals and a duty pulse A2. The identification pulse A1 is detected by the identification pulse detection means 12.

Reference numeral 13 denotes a timer, which inputs the enable pulse B to the counter 15 while receiving the duty pulse A2, as shown in FIG. 3 (b). Reference numeral 14 is a high frequency clock pulse generating means, which is a first gate G1.
And the high frequency pulse C shown in FIG. 3C is transmitted to the second gate G2. The first gate G1 opens the gate only when the duty pulse A2 is H, and inputs the gate pulse D1 shown in FIG. Further, the gate G2 opens the gate only when the duty pulse A2 is L, and the gate pulse D2 shown in FIG.
Enter in 5. Of course, the gate G1 may be opened at L time and the gate G2 may be opened at H time.

The counter 15 counts up the gate pulse D1 at the time of H and counts down the gate pulse D2 at the time of L (see FIG. 3 (f)). The counter 15 is connected to the CPU 16.

FIG. 4 shows the pulse width of the pulse output from the counter 15 according to the change in the light amount.
The TH value is a threshold value for A / D conversion.
In the figure, the solid line a is a waveform at the normal time, in which case the count value of the count-up and count-down is 0, and the pulse width of the pulse E1 is the normal value L1. The broken line b is a waveform when the light amount is abnormally reduced due to the disconnection. In this case, the count value is negative and the pulse width L2 of the pulse E2 is smaller than the normal value L1. The chain line c is a waveform when the light amount abnormally increases due to an excessive light amount of the light source, in which case the count value is positive and the pulse E
The pulse width L3 of 3 is larger than the normal value L1. Figure 5
The waveforms of the pulses E1, E2, E3 output from the counter 15 are shown. That is, when the light amount abnormally decreases, the pulse width of the pulse output from the counter 15 decreases, and when the light amount abnormally increases, the pulse width L3 increases, so that the light amount abnormality can be easily detected.

[0014]

As described above, according to the present invention,
With a simple configuration, it is possible to easily detect an abnormality in the amount of light due to a break in the optical fiber.

[Brief description of drawings]

FIG. 1 is a block diagram of an electric circuit according to the present invention.

FIG. 2 is a block diagram of an optical transmission device according to the present invention.

FIG. 3 is a waveform diagram according to the present invention.

FIG. 4 is a waveform diagram according to the present invention.

FIG. 5 is a waveform diagram according to the present invention.

[Explanation of symbols]

 11 Reference Signal Generating Means 12 Identification Pulse Detecting Means 14 High Frequency Clock Pulse Generating Means 15 Counter G1 First Gate G2 Second Gate

Claims (1)

Claim: What is claimed is: 1. A reference signal generating means for generating a reference identification signal composed of an identification pulse and a duty pulse, an identification pulse detecting means for receiving the reference signal and detecting the identification pulse, and a high frequency wave. A high-frequency clock pulse generating means for generating a clock pulse, a first gate whose gate opens only when the duty pulse is at H or L to allow passage of the clock pulse oscillated from the high-frequency clock pulse generating means, and the duty. A second gate whose gate opens only when the pulse is L or H to pass the clock pulse oscillated from the high-frequency clock pulse generating means, and a clock pulse input from the first gate and the second gate An abnormality detection device for an optical transmission system, which comprises an adding counter.