JPH0436439B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an anemometer that transmits signals using optical fibers.

[Conventional technology]

As shown in Figure 4, a conventional anemometer using optical fibers uses multiple optical fibers to form a transmission system: one for the light source, one for the wind speed, and four to five for the wind direction. Signal conversion of wind direction and wind speed is performed by turning on and off lights using a code board such as a binary code or an alternating binary code for wind direction, and turning on and off lights by rotating a propeller proportional to the wind speed for wind speed. , all composed of optical circuits.

[Problems to be solved by the invention]

The transmission distance of an anemometer transmitter using optical fiber is [(light level of light source) - (minimum light receiving level of converter)] and [transmission loss of optical circuit = amount of attenuation of light]
In the case of multiple optical transmission systems, it depends on the one with the largest loss. Conventional wind speed and direction anemometer transmitters using optical fibers are constructed using multiple optical fibers. There are variations in the amount of attenuation of light in the paths, and it is difficult to maintain the same amount of attenuation. Anemometer transmitters using optical fibers have a characteristic that they are resistant to lightning damage because the transmission system is an insulating material.The present invention aims to solve the above-mentioned problems while maintaining this characteristic. do.

[Means to solve the problem]

The present invention has a battery-powered electronic circuit inside the transmitter, transmits wind direction data in series, transmits signals with a transmission period inversely proportional to wind speed, and transmits wind direction and speed data through a single optical fiber. This is how it was done.

[Effect]

Since there is only one optical fiber in the transmission system, there is no variation in maximum transmission distance due to variation in transmission loss as in conventional multi-core optical fiber transmission systems. In addition, in the conventional system, the light emitted from the light source of the converter travels back and forth to the transmitter and then to the converter, but in the present invention, the light source is on the transmitter side, and the light source is connected between the transmitter and the converter. Therefore, if the light source level and the minimum light reception level of the converter are the same as before,
The transmission distance will be doubled. Furthermore, since optical loss inside the transmitter essentially does not occur in the present invention, the transmission distance can be extended accordingly.

【Example】

Methods for converting wind direction and speed can be roughly classified into contact type and non-contact type, but the non-contact type is advantageous in terms of S/N. An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the wind direction is determined by converting the rotation of the tail into wind direction digital data using a code plate. In the non-contact method, the wind direction detection section is constructed by combining several sets of LED light sources and photodetection elements, and generates parallel digital data by turning on and off the light of each bit of the code plate. On the other hand, the wind speed is determined by detecting the rotation of the propeller by a wind speed detection section to obtain a pulse signal of a number proportional to the wind speed. Possible methods for the wind speed detection unit include those that use light reflection or transmission by an LED and a photodetection element similar to the wind direction, and those that use magnets and coils, but in order to reduce power consumption, magnets The coil method is advantageous. Furthermore, in order to increase the efficiency of the coil, a magnetic material can be used as the core to increase detection sensitivity. Next, the power supply control circuit 1 is activated by a wind speed pulse signal and turns on the power. When the power is turned on, the clock generator and bit counter section 2 start operating, and the clocks are connected in parallel.
It is supplied to the serial converter 3. Parallel-serial converter 3
takes in the wind direction data and sends it one bit at a time to the electric-to-optical converter (=E/O section) 4 by the clock, which becomes an optical signal and is transmitted via the optical connector 5 to the optical fiber 6 to the converter. On the other hand, the clock generator and bit counter section 2 generates a stop signal when the necessary number of bits are sent out, stops the bit counter 2, and at the same time turns off the power to the power supply control circuit 1, completing one sequence. Figure 2 shows a timing diagram. Next, when the wind speed pulse signal comes, the above sequence is repeated. The converter receives the optical signal, performs O/E conversion, and then converts the wind direction into series/parallel, and the wind speed according to the transmission period T.
Measure the wind speed and calculate the wind speed value. The present invention is thus a method in which the wind direction data is a serial digital signal, and the wind speed signal is transmitted according to the transmission period of this wind direction signal. By transmitting the wind speed signal in this manner, the circuit inside the transmitter can be simplified, power consumption can be reduced, and the operating time (= battery life) can be extended.
In addition, in order to extend the operating time of electronic circuits,
The ratio of ON time to OFF time is large, and the average current consumption is low, eliminating the need for battery replacement for several years. In addition, as an example, if a power supply voltage drop signal is input as shown in the timing diagram of Fig. 3, and an alarm is generated when the power supply voltage falls below a certain voltage, it is possible to easily know when it is time to replace the battery. I can do it. Furthermore, if this electronic circuit is completely sealed inside the transmitter and the signal is extracted from the outside only through an optical connector, it can be used in explosion-proof areas such as natural gas. This transmission method is also possible as a transmission method using a conventional metal cable.

【Effect of the invention】

(a) In the present invention, n-bit wind direction parallel digital data is supplied to the parallel-to-serial converter 3 and a start bit is added to form a wind direction digital serial signal.
Since it is designed to be transmitted via a real fiber cable 6, the wind direction data is always a digital signal with a predetermined number of bits, and the signal format to be sent out is the same, so if a different signal format is sent, it will be It is immediately obvious that the data is incorrect, and the data can be rejected. Furthermore, since the wind direction data is a digital signal with a predetermined number of bits, it is also possible to add a check bit such as a power drop signal or a parity check bit in advance and transmit it. (b) After the clock generator and bit counter unit 2 send out the necessary number of bits, the power supply control circuit 1
Since one sequence ends by turning off the power, power consumption can be minimized.
It is possible to extend the life of the power supply battery, which has practical merits in remote mountainous areas.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a block diagram of the present invention;
The figure is a signal timing diagram of each part of the present invention, and is an embodiment in which the wind direction is 4 bits. FIG. 3 shows the transmission waveform of an embodiment in which a power supply voltage drop signal is added to the last bit. FIG. 4 is an example of a conventional optical anemometer transmitter. FIG. 5 shows another embodiment. 1 is a power supply control circuit, 2 is a clock generator and bit counter section, 3 is a parallel-to-serial converter section,
4 is an E/O conversion unit, 5 is a transmission optical connector,
6 is an optical fiber cable, 7 is a reception optical connector, 8 is an optical reception converter, a is an example of a wind speed pulse signal, b is a power ON signal, c is a clock signal, d is a stop signal , e is a transmitted signal.

Claims (1)

[Claims] 1 Turn on the power to the power control circuit 1 using a wind speed pulse signal proportional to the wind speed due to the rotation of the propeller.
At the same time, the clock generator and bit counter section 2 are activated to supply a clock pulse signal to the parallel-to-serial converter section 3. At the same time, the rotation of the tail is detected, and the
The bits of wind direction parallel digital data are supplied to the parallel-to-serial converter 3, and the bits of the wind direction digital serial signal to which the start bit is first added and the wind speed signal are set as the transmission period T of the wind direction signal to the electric-to-optical converters 4 and 1. On the other hand, after transmitting the required number of bits, the clock generator and bit counter unit 2 stops counting bits and at the same time turns off the power to the power supply control circuit 1 to complete one sequence. Anemometer transmission method designed to complete the process.