JPH0782598B2 - Control method of optical isolation measurement system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for an optical isolation measuring system in which a measuring end side and a measuring device side are electrically insulated by an optical fiber cable.

[0002]

2. Description of the Related Art When a high voltage signal is to be measured, it is desirable to electrically insulate the measuring end side and the measuring device side for the safety of the measuring device and the operator. As this method, an insulating transformer, an optical coupling means, or the like is used, but the isolation by the optical coupling means is suitable in terms of safety, reliability, lightness, cost, and the like.
FIG. 2 is a block diagram showing a typical configuration of an optical isolation measuring apparatus in which a measuring end side and a measuring instrument side are insulated by using an optical fiber cable. The measurement end side includes the probe 2 and the signal transmitter 4, and the measurement device side includes the measurement control device 6 and the display 8. The signal transmitter 4 adjusts the electric signal from the probe 2 to a desired level through an attenuator and an amplifier, converts the electric signal into a corresponding optical signal by an electric / optical converter, and through the first optical fiber cable 5. The measurement controller 6 is supplied. The measurement control device 6 converts the input optical signal into a corresponding electric signal via an optical / electrical signal converter to obtain a measurement value and displays the measurement result on the display 8. Further, the measurement control device 6 converts the control signal into an optical control signal by the electric / optical signal converter, and supplies this to the signal transmitter 4 via the second optical fiber cable 7. The signal transmitter 4 converts the optical control signal into an electrical control signal by an optical / electrical signal converter, and the attenuator and the amplifier are controlled by the electrical control signal.

[0003]

In the above-mentioned conventional example, the first optical cable 5 is used only for transmitting the signal under measurement from the measuring end side to the measuring device side, and the second optical cable 7 is
It is used only to supply control signals from the measuring device to the measuring end. Therefore, since only the signal under measurement is transmitted from the signal transmitter 4 on the measurement end side to the measurement control device 6, the information on the display 8 obtained from this measurement result is the magnification (or attenuation ratio) of the probe 2. ) Is not considered. Therefore, the operator must calculate the actual measurement value in consideration of the magnification (attenuation ratio) of the probe 2 used. For example, if the measured value displayed is 20V but the probe magnification is 100: 1, it is actually 2KV,
If the magnification is 1000: 1, it must be converted to 20 KV.

It is obvious that the cost will be greatly increased by newly providing the dedicated optical cable for transmitting the measurement related information such as the magnification of the probe. Further, when the measurement related information is periodically transmitted through the existing first optical fiber cable 5 in a time division manner, the transmission of the signal under measurement is periodically interrupted, which causes a so-called dead time of measurement. This is not preferable because it increases the period.

Therefore, an object of the present invention is to control an optical isolation measuring device which can minimize the dead time of the signal measuring operation with a simple structure when transmitting the measurement related information such as the magnification of the probe to the measuring device side. Is to provide a method.

[0006]

SUMMARY OF THE INVENTION The present invention provides a signal transmitter for outputting an optical signal to be measured corresponding to an electric signal to be measured received from a measurement probe, and a signal transmitter for receiving the signal from the signal transmitter via a first optical fiber. And a signal measurement controller for controlling the signal transmitter by measuring the measured optical signal and supplying a control signal to the signal transmitter via a second optical fiber according to the measurement result. A method of controlling a vibration measurement system is provided.

In the present invention, the signal transmitter sets the optical output to a predetermined level only when the content of the measurement-related information is updated, such as when the power is turned on or when the probe is replaced.
When the signal measurement control device detects that the signal level of the first optical fiber has reached a predetermined level, the signal measurement control device supplies a request signal to the signal transmission device via the second optical fiber, and in response to the request signal, the signal transmission device. Sends the updated measurement-related information to the signal measurement controller via the first optical fiber.

[0008]

FIG. 3 is a block diagram showing the configuration of an optical isolation measuring system suitable for using the present invention, and the portions corresponding to the configuration of FIG. 2 are designated by the same reference numerals. . The probe 2 is a signal input terminal 1 of the signal transmitter 4.
It is connected to 0 as well as to the other connection end 12. The signal under measurement is input from the probe 2 to the variable attenuator 14 via the signal input terminal 10. The connection end 12 is for receiving information such as the magnification of the probe 2 and for supplying necessary power and control signals to the probe, and the probe 2 and the probe I / F (via the connection end 12). Necessary signals and electric power are exchanged with the interface 16. As described above, an example of a probe connector that can receive not only the signal under measurement from the probe but also information such as the magnification of the probe and supply of power and control signals is disclosed in Japanese Examined Patent Publication No. 3-11064, "Modified BNC connector Is disclosed in detail. A large number of connection pins can be connected to such a probe connector outside the signal path to be measured, and various types of measurement probes such as passive probes, active probes, current probes, etc. can be connected, and only the signal to be measured can be connected. It is also easy to exchange other measurement related information. Such measurement related information is exchanged with the controller 18 including a microprocessor.

The output of the variable attenuator 14 is the variable gain amplifier 2
0 is supplied to the limiter 22 after being amplified by an amplification factor determined by the control of the controller 18. The limiter 22 limits the output value so as not to drop below a predetermined value regardless of the value of the input signal. This limiter output is converted into a corresponding optical signal by an E / O (electrical / optical signal converter) 24. This optical signal is transmitted to the measurement control device 6 via the first optical fiber 5. The optical control signal from the measurement control device 6 is supplied to the O / E (optical / electrical signal converter) 26 of the signal transmitter 4 via the second optical fiber 7 and converted into an electrical signal. According to this signal, the controller 18 controls and adjusts the signal transmitter 4.

In the measurement control device 6, the signal under measurement from the first optical fiber 5 is converted into an electric signal by the O / E 28,
Further, it is converted into a digital signal by an A / D (analog / digital converter) 30 and supplied to the system controller 32. The control signal generated by the system controller 32 is the E / O 34
Is converted into an optical control signal and is supplied to the signal transmitter 4 via the second optical fiber 7. Based on this control signal, various measurement parameters are controlled or adjusted. The system control device 32 displays the measurement result on the display 8 via the display I / F 36.

FIG. 4 shows the voltage of the electric signal to be measured and E / O2.
4 is a graph showing the relationship with the power of the optical output signal of FIG.
When the signal under measurement changes in the range of -V to + V volts, the optical power changes in the range of A to C watts, as is apparent from the portion indicated by the solid line on the graph. At this time, the voltage of the electric signal to be measured and the power of the optical signal have a linear relationship, and the voltage of the electric signal to be measured can be accurately measured by measuring the optical power. As can be seen from the graph, no matter how the measured signal voltage changes, the optical power never falls below the limit level due to the action of the limiter 22. E
The / O24 is controlled by the controller 18, and the output optical signal of the E / O24 can be forcibly set to a predetermined level regardless of the input voltage from the limiter 22. This predetermined level is chosen to be less than the limit level, for example 0 watts. The controller 18 of the signal transmitter 4 monitors the signal from the probe I / F 16, and sets the output optical signal level of the E / O 24 to a predetermined level (only when the magnification of the measurement probe 2 and other measurement-related information are updated). For example, 0 watt) is forcibly set.
Such update of the measurement related information usually occurs when the power is turned on or when the measurement probe is replaced, and does not occur during normal measurement operation. Therefore, the controller 18 does not need to constantly monitor the measurement-related information, and may detect the information only when the power is turned on and when the probe is replaced, and compare it with the previous information.

FIG. 1 is a flowchart showing an embodiment of the operation procedure of the system controller 32 in the measurement controller 6 of the optical isolation measuring system of FIG. In step 40 after the start, the system controller 32 detects the data from the A / D 30 and executes the measurement of the input signal under measurement. In the next step 42, it is judged whether or not the optical signal level of the first optical fiber 5 is a predetermined level (0 watt in this case). If the answer is no, a normal measurement result has been obtained, and the process proceeds to step 44 to display the measurement result. afterwards,
Return to step 40 to perform the next measurement. If the answer in step 42 is YES, E of the signal transmitter 4
The output optical signal level of / O24 is forcibly set to a predetermined level (for example, 0 watt), which means that there is some change in measurement-related information such as the magnification of the probe. Therefore, in step 46, the system controller 32 supplies the request signal to the signal transmitter 4 via the E / O 34 and the second optical fiber 7. The controller 18, which receives the request signal from the O / E 26, transmits the measurement-related information from the probe I / F 16 to the measurement control device 6 via the E / O 24 and the first optical fiber 5. In the next step 48, the system controller 32 determines whether or not the updated measurement-related information is detected from the signal transmitter 4, and if it is detected, in step 44, it is correctly determined based on the updated measurement-related information. Display the converted measurement results. At this time, if the measurement-related information is information indicating an abnormality of the probe (for example, an abnormality in the power supplied to the active probe), an abnormality warning of the measurement result may be displayed. If no measurement-related information is received in step 48, it can be determined that some abnormality has occurred on the signal transmitter 4 side, and therefore step 50
Displays an abnormal warning or invalid measurement result.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described herein, and various modifications and changes can be made as necessary without departing from the gist of the present invention. It will be apparent to those skilled in the art that changes can be made. It should be noted that although the information about the measurement probe is monitored as the measurement related information in the embodiment, this measurement related information includes other information. For example,
Since the signal transmitter operates in a high voltage system, it is driven by a built-in battery. However, the output voltage or current of the built-in battery may be monitored and a warning may be displayed when the output voltage or current falls below a predetermined value.

[0014]

As described above, according to the control method of the optical isolation measuring system of the present invention, the existing optical fiber for transmitting the signal under measurement between the measuring end and the measuring device is used to measure the measurement related information. Changes are transmitted only to the measuring device side, so there is little additional hardware,
The automatic display of the correct measurement result can be easily realized, and the so-called dead time for interrupting the measurement operation can be kept to a minimum.

[Brief description of drawings]

FIG. 1 is a flowchart showing a control procedure of an embodiment of the present invention.

FIG. 2 is a block diagram showing a typical configuration of an optical isolation measurement system.

FIG. 3 is a block diagram showing the configuration of an embodiment of a measurement system suitable for implementing the present invention.

FIG. 4 is a graph showing the relationship between the voltage of the signal under measurement of FIG. 3 and the power of the optical signal output to the first optical fiber.

[Explanation of symbols]

 2 measurement probe 4 signal transmitter 5 first optical fiber 6 measurement controller 7 second optical fiber 8 indicator

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Claims (1)

[Claims] 1. A signal transmitting device for outputting an optical signal under measurement corresponding to an electrical signal under measurement received from a measuring probe, and measuring the optical signal under measurement received from the signal transmitting device via a first optical fiber. A control method for an optical isolation measurement system including a signal measurement control device for controlling the signal transmission device by supplying a control signal to the signal transmission device via a second optical fiber according to the measurement result. Then, the signal transmission device sets the optical output to a predetermined level only when the measurement-related information is updated, and when the signal measurement control device detects the predetermined level of the first optical fiber, it outputs a request signal. The signal transmission device is supplied via the second optical fiber to the signal transmission device, and the signal transmission device updates the measurement related information in response to the request signal via the first optical fiber. A method for controlling an optical isolation measurement system, which comprises transmitting the signal to a constant control device.