JP2000235055A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of types of external controllers while keeping a compact size. SOLUTION: This measuring device 1 is provided with a current supplying means 21 for supplying a prescribed current to a connected external device 2a via a type discriminating connection terminal (a), and a discriminating means for discriminating a type of the external equipment 2a based on a terminal voltage Va generated in the terminal (a) under a condition supplied with the prescribed current. The discriminating means is provided with a voltage detecting element 12a for detecting a terminal voltage with at least three stages of resolutions to generate detection signals, a memory part 15 for storing as a type data the types of the plural external equipments 2a corresponding to the plural detection signals generated in response to the resolutions respectively, and a discriminating part 12 for discriminating the type of the connected equipment 2a based on the detection signals and the type data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring apparatus which is capable of remote control by an external device such as an external controller.

[0002]

2. Description of the Related Art As a device for supplying a large current (for example, 20 A) between a housing of a device to be tested and a ground terminal thereof and measuring a resistance between the two in that state, a so-called protection continuity test device has been conventionally used. Are known. Also, a high voltage (for example, 5 V) is applied between the housing of the device under test and its AC input terminal.
As a device for supplying KV) and measuring the leakage current in that state, a so-called withstand voltage test device is conventionally known. Since these measuring devices output a large current or a high voltage to the outside of the device, from the viewpoint of preventing accidents, they are generally configured so that the measuring device body can be controlled by an external controller. In this case, various types of external controllers are prepared in advance so as to meet the requirements of the operation specifications of the operator. Therefore,
This type of measurement device has a built-in identification means for identifying the model of an external controller connected to the device.

As shown in FIG. 3, an external controller 2a to 2d (hereinafter referred to as "external controller 2" when no distinction is made), and only the external controller 2a is shown in FIG. .), And a control unit 62 for identifying the model of the external controller 2 connected to the connector 11. In this case, the power supply voltage B is supplied to the connection terminals a to e of the connector 11 via the pull-up resistors 63, 64, 24 to 26. When the external controller 2 is connected, the control unit 62 controls the connection terminals a and b of the connector 11.
Of the external controller 2 is determined based on a combination of the two terminal voltages. For this reason, the control unit 62 stores in advance the model data table for specifying the correspondence between the combination of the two terminal voltages and the model of the external controller corresponding to the combination in the internal RAM. As a result, the operator has four types of external controllers 2a to 2a.
Any one of the models 2d can be connected to the measuring device 61. Further, the control unit 62 recognizes a control command from the external controller 2 by monitoring a voltage change of the connection terminals c to e to low level. In this case, each control command input via the connection terminals c to e is determined in advance for each model of the external controller 2. For this reason, the control unit 62 stores the content of each control command for each model of the external controller 2 in the built-in RAM.

On the other hand, for example, the external controller 2a
In addition to a connector 31 for connecting to the connector 11 of the measuring device 61, the remote control switch includes a momentary-type start / stop switch 32 and an alternate-type connection confirmation switch 33. I have.

In this measuring device 61, when the connector 31 of the external controller 2a is connected to the connector 11, the connecting terminals a and f of the connector 31 are connected to the ground of the measuring device 61 via the connecting terminal f of the connector 11. It becomes a common potential with the potential. Therefore, the connection terminal a of the connector 11
Changes from a high level to a low level. Thereby, the control unit 62 detects that the terminal voltage of the connection terminal a is at the low level and the terminal voltage of the connection terminal b is at the high level, and refers to the model data table of the built-in RAM to connect. The type is identified as the external controller 2a. Next, when the connection confirmation switch 33 on the external controller 2a side is operated, the terminal voltage of the connection terminal e of the connector 11 is maintained at a low level. As a result, the control unit 62 recognizes that the remote control state has been set by the external controller 2a.

Next, when the start / stop switch 32 is operated on the external controller 2a side, the control unit 62
Detects that the start command has been input by detecting that the terminal voltage of the connection terminal c has changed to a low level. At this time, the control unit 62 starts a predetermined test. Next, when the terminal voltage of the connection terminal c once returns to the high level and then changes to the low level again, the control unit 62 recognizes that the stop command has been input, and stops the test. Thereafter, the control unit 6
2 recognizes the alternate input of the start command and the stop command each time the terminal voltage of the connection terminal c changes from the high level to the low level, and repeats the above processing. As described above, in the measuring device 61, when the connector 31 of the external controller 2 is connected to the connector 11, the model of the external controller 2 is identified based on the combination of the terminal voltages of the connection terminals a and b. be able to.

[0007]

However, the conventional measuring device 61 has the following problems. That is, in the conventional measuring device 61, the combination of the terminal voltages of the connection terminals a and b is set in accordance with the type of the external controller. Therefore, the configuration for recognizing the model can be simplified. However, on the other hand, when increasing the number of models of the external controller 2 to be connected, it is necessary to increase the number of connection terminals for model identification according to the number of the external controllers 2, so that the size of the connector 11 and the size of the measuring device 61 are increased. Will be invited.
Therefore, the conventional measuring device 61 has a problem that it is difficult to increase the number of connectable external controllers 2 while keeping the size small.

The present invention has been made in view of such a problem, and has as its main object to provide a measuring apparatus capable of easily increasing the number of models of an external controller while maintaining miniaturization. .

[0009]

In order to achieve the above object, a measuring apparatus according to claim 1 comprises a current supply means for supplying a predetermined current to a connected external device via a model identification connection terminal; In a measuring device comprising: an identification device for identifying a model of an external device based on a terminal voltage generated at a connection terminal for model identification in a state where is supplied, the identification device comprises:
A voltage detection unit that detects a terminal voltage with at least three levels of resolution to generate a detection signal, and stores a plurality of external device models as model data in correspondence with a plurality of detection signals generated according to the resolution, respectively. And a discriminator for identifying the model of the connected external device based on the detection signal and the model data.

[0010] In this measuring device, the storage unit previously stores, as model data, the correspondence between the terminal voltage of the model identification connection terminal according to the resolution of the voltage detecting unit and the model of the external device. Therefore, the identification unit identifies the model of the connected external device based on both the detection signal generated by the voltage detection unit and the model data stored in the storage unit. In this case, it is possible to connect external devices of a number corresponding to the resolution of the voltage detection unit to the measurement device. Therefore, by increasing the resolution, it is possible to connect many types of external devices by using only one model identification connection terminal. Further, when a plurality of model identification connection terminals are provided, it is possible to connect external devices of the number corresponding to the combination of terminal voltages at the model identification connection terminals.

According to a second aspect of the present invention, in the measuring apparatus of the first aspect, the voltage detecting section is constituted by an analog-digital converter for converting a terminal voltage into voltage data as a detection signal. Features.

The terminal voltage can also be detected by using, for example, a plurality of window comparator circuits as the voltage detector and monitoring the detection signals detected by the respective window comparator circuits. However, when the number of external devices to be connected is large, the number of window comparator circuits also increases, which may result in an increase in the size of the measuring device. In this measuring device, the analog-digital converter converts the terminal voltage into voltage data, and the identification unit identifies the type of the external device based on the voltage data and the model data. Therefore, the configuration can be simplified, and many types of external devices can be connected.

According to a third aspect of the present invention, in the measuring apparatus of the first or second aspect, the current supply means comprises a pull-up resistor connected to the model identification connection terminal. .

A constant current circuit is adopted as current supply means,
The constant current circuit may generate a terminal voltage at the model identification connection terminal by conducting a constant current to the external device through the model identification connection terminal. However, in the case of such a configuration, the use of a constant current circuit or the like may increase the cost of the measuring device. On the other hand, in this measuring device, a pull-up resistor is connected to the identification terminal, and a predetermined current is supplied to the external device via the pull-up resistor. Therefore, on the external device side, it is possible to specify the model by connecting an input resistor to the pull-up resistor in series and changing the resistance value of the input resistor. Therefore, the model of the external device can be reliably identified, and both the measuring device and the external device can be easily configured.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a measuring apparatus according to the present invention is applied to a protection continuity test apparatus will be described below with reference to the accompanying drawings. Note that the same components as those of the conventional measuring device 61 and the external controller 2a are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 1, a measuring device 1 includes a connector 11, a CPU 12, a measuring unit 13, a display unit 14, a ROM,
15, a RAM 16, resistors 21 to 26, and a transistor 27. The CPU 12 corresponds to an identification unit in the present invention, and incorporates an analog-digital converter 12a (hereinafter, also referred to as “A / D converter 12a”). The measurement unit 13 includes, for example, a current supply circuit and a measurement circuit. In this case, the current supply circuit supplies a large test current between the housing of the device under test and its ground terminal. On the other hand, the measurement circuit measures a voltage signal SIN generated between the housing and the ground terminal when the test current is conducted to the device under test, and based on the measured voltage, a conduction resistance between the two. And outputs measurement data to the CPU 12. The display unit 14 displays the measured conduction resistance and the model name of the external controller 2 connected to the device under the control of the CPU 12.

The ROM 15 corresponds to a storage unit in the present invention, and stores an operation program of the CPU 12, a model data table for identifying the model of the external controller 2, a control command data table, and the like. In this case, the model data table is used to specify the correspondence between the terminal voltage Va of the connection terminal a for identification in the connector 11 and the model of the external controller 2. Specifically, for example, the terminal voltage Va of 0.2 V is associated with the model of the external controller 2 a, and the terminal voltage V of 1.5 V is set.
a and the model of the external controller 2b
The terminal voltage Va of V corresponds to the model of the external controller 2c. Also, the control instruction data table is
It is used for specifying a control command corresponding to a control signal input via the connection terminals c and d for each model of the external controller 2. The RAM 16 temporarily stores the calculation result of the CPU 12 and the like.

The connection terminal a for identification of the connector 11 is C
The terminal voltage Va with respect to the ground potential is connected to the input port of the A / D converter 12a built in the PU 12 and to the power supply unit (not shown) via the resistor 21.
Are pulled up to the power supply voltage B. The connection terminal b is
Connected to the collector of transistor 27. In this case, when identifying the model of the external controller 2, the transistor 27 is activated when a high-level identification confirmation signal S2 is output from the output port of the CPU 12. Incidentally, biasing resistors 22 and 23 are connected to the base of the transistor 27, and the resistors 22 and 23 divide the identification confirmation signal S2 into a predetermined driving voltage. Connection terminal c ~
e is connected to the input port of the CPU 12 and is pulled up to the power supply voltage B by the resistors 24-26. In this case, the connection terminals c and d are connected to the external controller 2
Function as a control signal input terminal from the
Functions as a connection confirmation terminal for confirming connection when the external controller 2 is connected.

As the external controller 2, a large number of models are prepared in advance so as to be able to meet the requirements of the operation specifications of the operator. Hereinafter, as shown in the figure, two types of external controllers 2a and 2b are used. An example of use will be described. The external controller 2a includes a connector 31, a start / stop switch 32, and a connection confirmation switch 33. The connection terminals a and b of the connector 31
It is short-circuited by the short-circuit line 34. The external controller 2 b is the same as the connector 41, the resistor 42, the light-emitting diode 43 that is controlled to be turned on at the start of the test, the momentary start switches 44 and 45, the momentary stop switch 46, and the connection confirmation switch 33. Alternate type connection confirmation switch 47 with function
It is comprised including.

Next, the overall operation of the measuring apparatus 1 will be described.

First, when the external controller 2 is connected, the identification processing shown in FIG. 2 is executed. This process
This is a process for identifying the model of the connected external controller 2. First, a low-level connection confirmation signal S1
Is detected (step 51). In this case, when the connector 31 of the external controller 2a is connected to the connector 11 of the measuring device 1, for example, the connection terminal f of the connector 31
Becomes a common potential with the ground potential on the measuring device 1 side via the connection terminal f of the connector 11. Next, when the connection confirmation switch 33 on the external controller 2a side is operated,
When the connection terminal e of the connector 11 is maintained at the low level, the CPU 12 sends the low-level connection confirmation signal S
Find 1 As a result, the CPU 12 recognizes that the remote controller 2 has been set to the remote control state.

When the input of the connection confirmation signal S1 is detected, the CPU 12 outputs a high-level identification confirmation signal S2 to the resistor 22 (step 52). At this time, the transistor 27 operates to maintain the connection terminal b of the connector 11 at a low level. As a result, the external controller 2
On the “a” side, the connection terminals “a” and “b” of the connector 31 are commonly connected via the short-circuit line 34, so that the connectors 31 and 11
The terminal voltage Va at both connection terminals a is equal to the collector-emitter voltage (about 0.2 V) when the transistor 27 is on. at the same time,
The CPU 12 determines the terminal voltage V of the connection terminal a of the connector 11.
a is measured (step 53). In this case, the CPU 1
An A / D converter 12a built in 2 receives the terminal voltage Va and performs analog-to-digital conversion to generate voltage data.

Next, after measuring the terminal voltage Va, the CPU 12 stops outputting the identification confirmation signal S2 (step 54) and identifies the type of the external controller 2 (step 55). At this time, the CPU 12 compares the voltage value of the voltage data with the terminal voltage value in the model data table stored in the ROM 15. In this example, the terminal voltage Va is 0.2 V and is within, for example, ± 10% of the closest terminal voltage value (0.2 V). Based on the relationship, it recognizes that the external controller 2a has been connected. Thus, the identification process ends (step 56).

When the external controller 2b is connected and the identification confirmation signal S2 is output, the connection terminal a of the connector 11 is connected to the terminal voltage V represented by the following equation.
a is maintained. In the equation, the value B, the value VD, the value R21
And the value R42 mean the power supply voltage B, the forward voltage of the light emitting diode 43 (about 1 V), the resistance value of the resistor 21, and the resistance value of the resistor 42, respectively, and the collector-emitter voltage when the transistor 27 is on. Shall be ignored. Va = (B−VD) · R42 / (R21 + R42) + VD ···

In this example, when a series circuit of the resistor 42 and the light emitting diode 43 is connected in series to the resistor 21 having a predetermined resistance value, the terminal voltage Va, which is a divided voltage by the series circuit, becomes approximately Resistor 4 to 1.5V
2 is specified. Therefore, in this case, the CPU 12 searches the model data table in the ROM 15 and identifies that the model of the connected external controller 2 is the external controller 2b. Similarly, when an external controller 2 of another model is connected, the CPU 12
Identifies the model based on the voltage value of the terminal voltage Va and the model data table.

Next, when the start / stop switch 32 is operated on the external controller 2a side, the CPU 12
Detects the voltage change of the connection terminal c to low level,
By referring to the control command data table stored in the OM 15, it is recognized that the start command has been input. At this time, the CPU 12 causes the measuring unit 13 to output a test current to the device under test via the current output terminals 17a and 17b. Next, when the terminal voltage of the connection terminal c once returns to the high level and then changes to the low level again, the CPU 12 recognizes that the stop command has been input, and outputs the test current to the measuring unit 13. To stop. Thereafter, the CPU 12 recognizes alternate input of a start command and a stop command each time the terminal voltage of the connection terminal c changes to a low level,
The above processing is repeated.

On the other hand, when the external controller 2b is connected, the start switch 4
When the buttons 4 and 45 are simultaneously operated, the CPU 12 detects a voltage change of the connection terminal c to low level, and recognizes that the start command has been input by referring to the control command data table. At this time, the CPU 12 causes the measuring unit 13 to output a test current to the device under test via the current output terminals 17a and 17b, and outputs the identification confirmation signal S2 continuously for a predetermined time to drive the transistor 27. By doing so, the light emitting diode 43 is turned on. Thus, the operator can recognize that the test has started. Next, the external controller 2
When the stop switch 46 is operated on the side b, the CPU 1
2 detects a voltage change of the connection terminal d to a low level,
By referring to the control command data table, it is recognized that the stop command has been input, and the measurement unit 13 stops outputting the test current. Thereafter, the CPU 12
Recognizes that a start command has been input when the terminal voltage of the connection terminal c has changed to a low level, and
Recognizes that a stop command has been input when the voltage changes to a low level.

As described above, in the measuring apparatus 1, the CPU
The A / D converter 12a in the converter 12 converts the terminal voltage Va of the connection terminal a in the connector 31 (or 41) of the external controller 2 into voltage data, and the CPU 12 performs the conversion based on the voltage data and the model data table. The model of the external controller 2 is identified. Therefore, many models can be connected with a simple configuration.

Note that the present invention is not limited to the above-described embodiment, and the configuration can be appropriately changed. For example, in the embodiment of the present invention, an example in which three types of external controllers 2a to 2c are connected has been described. However, the number of models of the external controller 2 is not limited to this, and the A / D converter 1
As many as (for example, several tens) models can be connected as long as the voltage resolution of 2a allows. Even in such a case, it is not necessary to increase the number of connection terminals of the connector 11, so that the measuring device 1 can be reduced in size and cost. By using a plurality of model identification connection terminals, it is needless to say that the number of external controllers 2 equal to the number of combinations of terminal voltages of the plurality of model identification connection terminals can be connected.

In the external controller 2b, the light emitting diode 43 for notifying the test start state is connected in series to the connection terminal a for identification. However, the light emitting diode 43 is essentially unnecessary for model identification, 42 alone. Further, a constant current is supplied through the connection terminal a of the connector 11 of the measuring device 1 and a terminal voltage Va generated at the input resistance at the connection terminal a of the external controller 2 at that time is detected. The second model may be configured to be identified. Further, the terminal voltage value in the model data table shown in the embodiment of the present invention is not particularly limited, and can be appropriately changed.

Further, in the embodiment of the present invention, an example in which the present invention is applied to a protection continuity test device has been described. However, the present invention is not limited to this.
The present invention can be applied to all measuring devices configured to be capable of remote control, such as a power meter, a waveform generator, and various recorders.

[0032]

As described above, according to the measuring apparatus of the first aspect, the voltage detecting section detects the terminal voltage with at least three or more levels of resolution, and the identifying section detects the model of the external device with the detection signal and the model. By identifying based on data, 1
As a result of connecting a large number of external devices simply by using one model identification connection terminal, the number of external controllers can be easily increased while maintaining the miniaturization of the device. The model of the device can be reliably identified.

According to the measuring device of the second aspect,
Since the voltage detection unit is configured by the analog-digital converter, the configuration of the voltage detection unit can be simplified, and connection and identification of many types of external devices can be performed.

According to the measuring device of the third aspect,
By configuring the current supply means with a pull-up resistor,
The model of the external device can be reliably identified, and both the measuring device and the external device can be configured simply and inexpensively.

[Brief description of the drawings]

FIG. 1 is a block diagram of a measuring device 1 and external controllers 2a and 2b according to an embodiment of the present invention.

FIG. 2 is a flowchart of an identification process in the measuring device 1 according to the embodiment of the present invention.

FIG. 3 shows a conventional measuring device 61 and an external controller 2
It is a block diagram of a.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring device 2a, 2b External controller 11 Connector 12 CPU 12a Analog-digital converter 15 ROM 21 Resistance a Connection terminal

Claims (3)

[Claims] 1. A current supply means for supplying a predetermined current to a connected external device via a model identification connection terminal, and based on a terminal voltage generated at the model identification connection terminal when the predetermined current is supplied. A measuring device comprising: an identification unit that identifies a model of the external device, wherein the identification unit detects the terminal voltage with at least three or more levels of resolution to generate a detection signal;
A storage unit that stores the models of the plurality of external devices as model data in correspondence with the plurality of detection signals generated according to the resolution, and the detection signals and the model data indicating the models of the connected external devices. And a discriminating unit for identifying the measurement device based on the measurement result. 2. The measuring apparatus according to claim 1, wherein the voltage detecting section is constituted by an analog-digital converter that converts the terminal voltage into voltage data as the detection signal. 3. The measuring apparatus according to claim 1, wherein said current supply means is constituted by a pull-up resistor connected to said model identification connection terminal.