JP2003028939A - Portable resistance-welding measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give monitoring information useful for a user, regarding the state of the discharge capacity of a secondary battery built in as a power-supply battery. SOLUTION: An internal power-supply circuit 64 comprises a switching regulator 72, a reserve charging circuit 74, a charging control circuit 76, a battery- voltage monitoring circuit 78, a charging-current monitoring circuit 80 and the like, in addition to the secondary battery 70. The positive electrode of the secondary battery 70 is connected to the input terminal of the switching regulator 72 via a diode 82. The switching regulator 72, to which a DC voltage is input from the secondary battery 70 or external power-supply voltage input terminals 66, 68, generates DC power-supply voltages V0, V1, V2, V3, etc., at various voltage levels, used at respective inside parts of the portable resistance-welding measuring apparatus. The circuit 74 and the circuit 76 are actuated selectively. A CPU can grasp the state of the discharge capacity of the secondary battery 70 through the circuit 78.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable resistance welding measuring device for measuring welding conditions such as welding current, pressure, and energization time in resistance welding.

[0002]

2. Description of the Related Art Generally, a portable resistance welding measuring device is
The digital circuit of the information processing system and the analog circuit of the measurement system and the display system are mixed, and especially the analog circuit of the measurement system consumes a relatively large amount of power. To be done. For this reason, recently, a type using a secondary battery (storage battery) as a power battery has come into common use. In this type of device,
While connected to the AC adapter, the internal power supply circuit is driven by the external power supply voltage from the AC adapter, and at the same time the secondary battery is charged. When removed from the AC adapter,
In the battery drive mode, the secondary battery drives the internal power supply circuit instead of the AC adapter. From the internal power supply circuit, a power supply voltage of a predetermined voltage level is output toward each part in the device.

[0003]

In the portable resistance welding measuring device using the secondary battery as the power source battery as described above,
The discharge capacity (cumulative value of discharge amount) of the secondary battery gradually increases while operating in the battery drive mode. And
When the discharge capacity approaches the upper limit value, the battery voltage drops rapidly and the entire device does not function normally. Due to the quality control of resistance welding, such an outage of the resistance welding measuring device must be avoided. For this reason, it is very inconvenient and troublesome for the user such as a site worker to manage the charging time of the power supply battery on a daily basis.

The present invention has been made in view of the above problems of the prior art, and is a portable resistance welding for giving useful monitor information to a user regarding a discharge capacity state of a secondary battery incorporated as a power battery. An object is to provide a measuring device.

Another object of the present invention is to provide a portable resistance welding measuring device which allows a user to clearly and accurately understand the discharge capacity state of a secondary battery incorporated as a power supply battery at a glance. is there.

[0006]

In order to achieve the above object, a portable resistance welding measuring apparatus of the present invention has a built-in secondary battery, and uses resistance generated by discharging the secondary battery to perform resistance welding. In a portable resistance welding measuring device, which measures the welding conditions in the above, and displays the measured values of the welding conditions on the display on the operation panel, a battery voltage detection for detecting the voltage between the positive electrode and the negative electrode of the secondary battery. Means, and a battery capacity status display means for displaying the status of the discharge capacity of the secondary battery on the display based on the unique discharge load characteristic of the secondary battery and the battery voltage detected by the battery voltage detection means. It has a structure having.

In the above arrangement, since the progress of the discharge capacity is monitored and displayed on the screen based on the discharge capacity load characteristic of the secondary voltage built in as the power supply battery, the user is provided with appropriate monitor information. be able to.

In the portable resistance welding measuring apparatus of the present invention, a preferable mode of the battery capacity state display means is that the discharge capacity of the secondary battery is divided into a plurality of stages according to the discharge load characteristic, and each of the stages is divided into a plurality of stages. Monitoring voltage setting means for setting the voltage at the passing point as the monitoring voltage, and comparing the battery voltage detected by the voltage detecting means with the monitoring voltage, the current discharge capacity of the secondary battery is in any one of the stages. A discriminating means for discriminating whether or not it corresponds, and a mark for discriminating and displaying each stage of the discharge capacity are set, and a mark corresponding to the corresponding stage discriminated by the discriminating means is set for the discharge capacity of the secondary battery. It is configured to have a sign display means for displaying on the display as visual information that indicates the progress state stepwise.

According to this structure, the progress of the discharge capacity of the secondary battery is monitored stepwise and displayed on the screen, whereby the circuit structure and signal processing in the device can be simplified and the secondary battery can be simplified. The progress of the discharge capacity of the battery can be notified to the user in a simple and easy-to-understand form. In this configuration, it is preferable that the sign has a graphic representing a battery. By using such a battery graphic, any user can directly understand the state of the power supply battery (secondary battery).

Further, preferably, the battery capacity status display means may be configured to constantly display the status of the discharge capacity of the secondary battery on the display while the power switch is turned on. It may be configured to display at a predetermined position set in the screen area. With such a configuration, the user can be surely notified in real time of the state of the discharge capacity of the secondary battery.

It is also preferable that the battery capacity status display means displays on the display a margin until the discharge capacity of the secondary battery reaches a predetermined limit value. Even with such a configuration, any user can directly understand the state of the power supply battery (secondary battery).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an external configuration of a portable resistance welding measuring apparatus according to an embodiment of the present invention. This resistance welding measuring device has a palm-sized housing 10 that can be held with one hand. The front surface of the housing 10 is an operation panel, and a small flat panel display such as a liquid crystal display 12 is provided in the upper half portion, and a keyboard 14 is provided in the lower half portion.

The keyboard 14 includes, for example, an encoder key 16, a function key 18, and an enter key.
Key 20, power ON / OFF switch 22, hold
A key 24, a print key 26, an external key 28 and the like are included.

The encoder key 16 can rotate counterclockwise / clockwise and is used for scrolling the screen and moving the cursor. Further encoder key 1
6 can be pressed down, and by pressing down, it can play the same role as an enter key 20 described later. The function key 18 is used to select a function. The enter key 20 is used to confirm each operation. The power ON / OFF switch 22 is
Used to turn the power on (on) / off (off). The hold key 24 is used to hold the measurement result.
The print key 26 is used to display the print setting screen. The external key 28 is used to display the external connection setting screen.

The keyboard 14 includes various display lamps, such as a hold lamp 30, which are light emitting diodes.
An external power supply / charging lamp 32 and the like are also provided. The hold lamp 30 lights up while holding the measurement result. The external power / charging lamp 32 is lit when the device is connected to an AC adapter (not shown).

An openable / closable lid 34 is attached to one side surface or both side surfaces of the housing 10, and various external connection terminals (not shown) are provided inside the lid 34.
Among these external connection terminals, a plug socket for connecting an AC adapter is also included. Although not visible in FIG. 1, a plug / socket for connecting the cable terminals of the current sensor and the pressure sensor is provided on the top surface of the housing 10. Further, a lid (not shown) for replacing the battery is provided on the back surface of the housing 10.

On the display 12, measured values of welding conditions such as welding current, pressure, and energizing time are displayed in waveforms and numerical values. In this embodiment, a special screen area 12a is provided on the upper edge of the display 12, and the screen area 1
At the right corner of 2a, a battery status indicator 36 representing a battery is always displayed (to be exact, while the power is on). The display function of the battery status indicator 36 will be described in detail later. A schedule number (SCHEDULE) for managing the welding conditions or measurement conditions selected on the main screen is displayed in the left half of the screen area 12a (FIG. 3).

FIG. 2 is a block diagram showing the main structure of this anti-welding measuring device. The current sensor, for example, the toroidal coil 40 outputs an electric signal (current detection signal) DI representing a differential waveform of the current I flowing through the primary or secondary conductor 42 of the resistance welding machine during welding energization. The integrating circuit 44 integrates the output signal DI from the toroidal coil 40 and outputs a signal (current waveform signal) SI representing the waveform of the current I.

Output signal of the integrating circuit 44 (current waveform signal)
The SI is converted into a digital signal by the A / D converter 46, then temporarily stored in the buffer memory 48, and then written in the RAM 50. PLD (Programmable Logic Device) is used for data transfer of the current waveform signal in the A / D converter 46, the buffer memory 48 and the RAM 50, especially for the DMA transfer from the buffer memory 48 to the RAM 50.
It is performed under the control of 52.

The CPU 54 operates in accordance with a program stored in the ROM 56, executes required arithmetic operations and exchanges data and signals with each unit in the apparatus or the outside in order to perform various functions of the apparatus. . Input unit 58
Includes keys and switches on the keyboard 14, an input circuit, and the like, and provides keyed data to the CPU 54. The display unit 60 includes the display 12, a display circuit, and the like, and displays image data given by the CPU 54 on the display 12. The printer 62 has a housing 1
0 is connected to a printer terminal inside the lid 34 with a cable, and the image content on the display 12 is printed under the control of the CPU 54. In addition to the printer 62, various external devices such as a personal computer are input / output interfaces (not shown).
Data and signals can be exchanged with the CPU 54 via the.

The internal power supply circuit 64 supplies required power supply voltages V0, V1, V2, V3 ... The structure and operation of the internal power supply circuit 64 will be described in detail later.

When resistance welding is executed in the resistance welding machine, the current waveform signal obtained from the current measuring system (40, 44) as described above is used as data in the A / D converter 4.
6. The data is fetched into the RAM 50 via the buffer memory 48, and the CPU 54 calculates the current measurement value, for example, the current effective value or the conduction time measurement value based on the data of the current waveform signal.
The calculation result data is also stored in the RAM 50. And
After the resistance welding is completed, the current waveform and the measured value (numerical value) are switchably displayed on the screen of the display 12, as shown in FIG. 3, for example.

In the example of FIG. 3, the measurement result of the secondary current in the DC inverter resistance welding machine is displayed on the screen.
By clicking the "NEXT" and "BACK" buttons at the bottom right of the screen, you can switch the screen bidirectionally between the "current / energization time measured value (numerical value) display" screen and the "current waveform display" screen. Has become.

Although not shown in FIG. 2, when a pressure sensor is connected to the present apparatus, the pressure detection signal from the pressure sensor is also taken into the RAM 50 by the same signal processing as above, and the display 12 is displayed. The welding pressure waveform is displayed along with the current waveform.

FIG. 4 shows the structure of the internal power supply circuit 64.
The internal power supply circuit 64 has, as main constituent elements, a switching regulator 72, as well as a secondary battery 70.
It has a preliminary charging circuit 74, a charging control circuit 76, a battery voltage monitor circuit 78, a charging current monitor circuit 80 and the like.

The secondary battery 70 is, for example, a lithium ion secondary battery, and its positive electrode is connected to the input terminal of the switching regulator 72 via the diode 82. The positive terminal 66 of the external power supply voltage input terminals 66, 68 is also connected to the input terminal of the switching regulator 72 via another diode 84. While this device is connected to the AC adapter and the external power supply voltage Eo from the AC adapter is input to the input terminals 66 and 68, the external power supply voltage Eo is switched over in priority to the battery voltage of the secondary battery 70. It is supplied to the regulator 72. When the AC adapter is unplugged from the device, the battery drive mode is set and the voltage VB of the secondary battery 70 is supplied to the switching regulator 72.

The switching regulator 72 is a DC
A DC converter, which receives a DC voltage from the secondary battery 70 or the external power supply voltage input terminals 66 and 68, and which has various voltage levels to be used in each part of the apparatus. DC power supply voltages V0, V1, V2, V3 ... Is generated.

Between the positive side external power supply voltage input terminal 66 and the positive electrode of the secondary battery 70, a first charging circuit including a switching transistor 86 and a current detecting resistor 88, and a preliminary charging circuit 74 are provided. And a second charging circuit. In the first charging circuit, the switching transistor 86 is switching-controlled by the charging control circuit 76. The preliminary charging circuit 74 and the charging control circuit 76 are designed to selectively operate under the control of the CPU 54 (FIG. 2).

The battery voltage monitor circuit 78 includes a secondary battery 70.
Of the resistance voltage dividing circuit 90 connected between the positive electrode and the negative electrode (ground) electrode of the output voltage V of the resistance voltage dividing circuit 90.
An amplifier circuit 92 including an operational amplifier for amplifying B ', and C
A digital potentiometer 94 that outputs a variable analog reference voltage Vk under the control of the PU 54 and an output signal of the amplifier circuit 92 are compared with an output signal of the digital potentiometer 94, and a binary value (H / L) indicating a comparison result is displayed. Level) Comparator 9 consisting of operational amplifier for outputting signal
6 and.

The charging current monitor circuit 80 is an amplifier circuit 98 including an operational amplifier for amplifying the voltage (current detection voltage) between the terminals of the current detection resistor 88 in the first charging circuit.
And a variable analog reference voltage V under the control of the CPU 54.
a digital potentiometer 100 for outputting j,
The output signal of the amplifier circuit 98 is compared with the output signal of the digital potentiometer 100 to output a binary (H / L level) signal representing the comparison result.

FIG. 5 shows one charging method for charging the secondary battery 70 in the internal power supply circuit 64 from around zero volt to the set voltage Va. In this charging method, the secondary battery 7
A first phase of charging (preliminary charging) for raising the battery voltage VB of 0 from near zero volt to a predetermined passing point setting voltage Vp, and a constant current from the passing point setting voltage Vp to the target setting voltage Va The second phase charging (constant current charging) started up by the control and the third phase charging (constant voltage charging) in which the charging current flows after the target set voltage Va is reached by the constant voltage control are sequentially performed.

When the plug of the AC adapter is inserted into this device, a voltage detection circuit (not shown) detects that the external power supply voltage Eo from the AC adapter has started to be input and the CPU
Notify 54. Then, the CPU 54 sends a control signal to the preliminary charging circuit 74 to start the first phase charging (preliminary charging). On the other hand, the CPU 54 sets the digital potentiometer 94 of the battery voltage monitor circuit 78 to the data representing the passing point setting voltage Vp.

Due to the charging of the preliminary charging circuit 74, the charging voltage (battery voltage) VB of the secondary battery 70 increases with the passage of time. The precharge circuit 74 may perform constant current control. When the charging voltage (battery voltage) VB reaches the passing point setting voltage Vp, the output signal of the comparator 96 in the battery voltage monitor circuit 78 changes from the L level up to the H level.
Change to a level. The CPU 54 responds to the change (L → H) of the output signal of the comparator 96, and responds to the preliminary charging circuit 74.
Then, the first-phase charging (preliminary charging) is ended, and the charging control circuit 76 on the first charging circuit side is caused to start the second-phase charging (constant current charging).

In the second phase of charging (constant current charging), the charging control circuit 76 sets the charging current i by feeding back the charging current i in the form of a voltage drop iR88 from the resistor 88 having a known resistance value R88. The switching transistor 86 is switching-controlled at a predetermined high frequency so as to match the current value is. The charging control circuit 76 has a circuit (not shown) that detects or feeds back the charging voltage (battery voltage) VB of the secondary battery 70, and when the charging voltage (battery voltage) VB reaches the target set voltage Va. , The second phase charging (constant current charging) is stopped, and the charging is switched to the third phase charging (constant voltage charging). In the charging (constant voltage charging) of the third phase, switching control of the switching transistor 86 is performed so as to maintain the charging voltage (battery voltage) VB at the target set voltage Va.

When the charging shifts to the third phase (constant voltage charging), the charging current i gradually decreases. In the charging current monitor circuit 80, the digital potentiometer 100
The CPU 54 sets data indicating the predetermined charging current end point value ie as the comparison reference voltage Vj. Charging current i
Is reduced to the charging current end point value ie, the comparator 1
The output signal of 02 is changed from the L level up to that time to the H level, and the CPU 54 responds to the change of the output signal of the comparator, and terminates the charging (constant voltage charging) of the third phase. Charging is completed. If the time te required for the current charging is within the predetermined upper limit charging time Tm, the secondary battery 70 is considered to be normal,
Otherwise (when te> Tm), it is considered that the secondary battery 70 has failed or deteriorated, and a predetermined abnormality cancellation processing such as issuing an error message is performed.

While connected to the AC adapter,
The CPU 54 turns on the external power / charging lamp 32 on the keyboard 14. The user sees that the lamp 32 is lit, and confirms that this device is operating on the external power supply and that the internal power supply battery (secondary battery 70) is in the charging mode. I can confirm.

The secondary battery 70 maintains the battery voltage VB at the set voltage Va while being connected to the AC adapter even after being charged to the set voltage Va as described above.
When the AC adapter is unplugged from the device, the battery drive mode is set, and the battery voltage VB of the secondary battery 70 is supplied to the switching regulator 72 via the diode 82 as the primary voltage or the drive voltage.

When the device is continuously used in the battery drive mode, the secondary battery 70 continues discharging or supplying power to the switching regulator 72 side, and the battery voltage VB gradually decreases. Generally, a secondary battery has its own discharge capacity load characteristic according to its type or product.

FIG. 6 shows the discharge capacity load characteristics of a typical lithium ion secondary battery. In the present embodiment, the discharge capacity is divided into a plurality of stages, for example, four stages on the discharge capacity load characteristic of the secondary battery 70, and the voltages Va, Vb, Vc, Vd at the passage points of each stage, for example, the inlet points are determined. Set as monitoring voltage.

Of the four stages, the first stage is a stage in which the secondary battery 70 has begun to discharge (power supply) the switching regulator 72, and is still short, and the battery voltage VB is relatively steep. The slope decreases. The second stage is a stage in which the discharge (power supply) operation of the secondary battery 70 is stable, and the battery voltage VB gradually decreases with a gentle gradient. The third stage is a stage where the secondary battery 70 is in a recessed state, and the battery voltage VB drops steeply. The fourth stage is the final stage in which the discharge capacity of the secondary battery 70 is close to the limit, the battery voltage VB drops to a considerably low level, and the switching regulator 72 can no longer be normally driven, and as a result, in the device. The normal operation of each part of can not be guaranteed.

In the case of this setting example, the monitoring voltage Va in the first stage is the same as the charging setting voltage Va. During the battery driving mode, the load capacity of the battery voltage 70 goes through each step in the order of →→→ with time.
Indicates the monitoring voltage Va, Vb, V
By sequentially setting c and Vd in the digital potentiometer 94 and monitoring the change in the output signal of the comparator 96, the discharge capacity of the secondary battery 70 can be changed at each stage.
You can know when you entered. Thus, the CPU
Reference numeral 54 indicates a secondary battery 7 through the battery voltage monitor circuit 78.
It is possible to constantly monitor or grasp at which stage the discharge capacity of 0 is currently.

On the other hand, in the ROM 56, the display 12
The image data of the battery status indicator 36 that is always displayed in the right corner of the upper edge image area 12a is stored. This battery status indicator 36 is a battery figure (fixed image part) A in the shape of a battery.
And 0 to 3 bars (variable image part) B included in the battery figure A (body part).

As shown in FIG. 7, the display contents of the variable image portion, that is, the number of the bars B is different from each other in each stage of the discharge capacity load characteristic of the secondary battery 70.
(1), 36 (2), 36 (3), 36 (4) are set. More specifically, for the stage, a marker 36 (1) including three bars B in the battery graphic A is set. For the stage, a mark 36 (2) containing two bars B in the battery diagram A
Is set. 1 for battery diagram A for steps
A marker 36 (3) including the bar B of the book is set. For the stage, a mark 36 (4) is set which does not include any bar B in the battery figure A. As described above, in the battery state indicator 36 of this embodiment, the number of bars B included in the battery pattern A is a barometer indicating the remaining capacity of the discharge capacity of the secondary battery 70, that is, a margin until reaching the limit value. Become.

When the battery drive mode is started (or when the charging operation for the secondary battery 70 as described above is completed), the CPU 54 causes the digital potentiometer 94 of the battery voltage monitor 78 to enter the second stage entry point. The data of the corresponding monitor voltage Vb is set. And
At the right corner of the upper edge image area 12a of the display 12, a battery status indicator 36 (1) indicating a stage is displayed. While the battery status indicator 36 (1) is being displayed, the user
It is possible to confirm that the power supply battery (secondary battery 70) has been charged and is in a very short time, so that the time for recharging is a long way off.

After that, the switching regulator 72
When the secondary battery 70 is continuously discharged or fed to the battery voltage VB, the battery voltage VB drops to the monitoring voltage Vb, and the output signal of the comparator 96 in the battery voltage monitor 78 changes from the L level to the H level. The CPU 54 reads the change (L → H) in the comparator output signal and detects that the discharge capacity of the secondary battery (70) has shifted from the first stage to the second stage.

When it is detected that the discharge capacity of the secondary battery (70) has shifted from the first stage to the second stage as described above, the CPU 54 displays in the right corner of the upper edge image area 12a of the display 12. The battery state indicator 36 (1) is switched to the indicator 36 (2) corresponding to the second stage. Then, the digital potentiometer 94 of the battery voltage monitor 78 displays the monitoring voltage V corresponding to the entry point of the third stage.
Set the data of c. Then, at this point VB
Since> Vc, the output signal of the comparator 96 returns to the L level. The user sees the battery status indicator 36 (2) every time he or she looks at the display 12, and since the battery figure A includes two bars B, the power source battery (secondary battery 70) You can see that charging is still ahead.

When the secondary battery (70) is continuously discharged or fed to the switching regulator 72, and the battery voltage VB drops to the monitoring voltage Vc, the output signal of the comparator 96 in the battery voltage monitoring unit 78 is kept until then. Changes from L level to H level. The CPU 54 reads the change (L → H) in the comparator output signal and confirms that the discharge capacity of the secondary battery (70) has shifted from the second stage to the third stage.

When the transition from the second stage to the third stage is confirmed as described above, the CPU 54 from that time point displays the marker 36 (3) of the third stage at the right corner of the upper edge image area 12a of the display 12. indicate. On the other hand, the data of the monitoring voltage Vd corresponding to the entry point of the fourth stage is set in the digital potentiometer 94 of the battery voltage monitoring unit 78. Then, since VB> Vd at this point, the output signal of the comparator 96 returns to the L level. For the user, looking at the display 12, the battery status indicator 36
Since there is only one bar B in (3), it is possible to know that the secondary battery (70) is dead and to recognize that it is time to recharge.

Normally, at this stage, the device may be connected to the AC adapter. However, if the battery voltage is inadvertently neglected, the battery voltage VB drops to the monitoring voltage Vd, and the output signal of the comparator 96 in the battery voltage monitor 78 changes from the L level to the H level. CPU 54
Reads the change (L → H) in the comparator output signal and confirms that the discharge capacity of the secondary battery 70 has changed from the third stage to the fourth stage. Then, from that point, the fourth stage marker 36 (4) is displayed in the right corner of the upper edge image area 12a of the display 12.

When the user sees that there is no bar B in the battery status indicator 36 (4) and finally knows that the battery drive mode has reached the limit, he / she can no longer connect to the AC adapter to connect the external power source. / You can be aware that you should not use this device unless you are in charging mode.

In the above example, in order to detect the time when the discharge capacity of the secondary battery 70 enters each stage ,.
The CPU 54 advances one step in the order of the monitoring voltage V.
The values a, Vb, Vc and Vd are sequentially set in the digital potentiometer 94, and changes in the output signal of the comparator 96 are monitored. As another method, the CPU 54 increments or decrements the set value of the digital potentiometer 94 within a predetermined range at a constant cycle to detect the voltage VB of the secondary battery 70 at that time from the monitoring of the output signal of the comparator 96. Then
The detected battery voltage VB and monitoring voltage (Va, Vb, Vc,
The relevant or current stage can be determined from the comparison with Vd).

As described above, in this embodiment, the state of the discharge capacity of the secondary battery 70 incorporated in the internal power supply circuit 64 as the power supply battery is monitored based on the discharge capacity load characteristic. Moreover, since it is displayed on the screen, it is possible to provide the user with accurate monitor information.

Further, the discharge capacity is divided into a plurality of steps, for example, four steps on the discharge capacity load characteristic, and the progress state of the discharge capacity is monitored stepwise and displayed on the screen, so that the circuit configuration and the signal processing in the apparatus are performed. Easy to use, and the secondary battery 70
It is possible to inform the user of the progress state of the discharge capacity in a simple and easy-to-understand form.

In addition, a special display area or position (preferably a corner position of the screen) for providing monitor information relating to the state of the secondary battery 70 is set in the screen area on the display 12, and the power switch is set. Since the monitor information is constantly displayed on the screen at the display position regardless of the display content of the main screen area while is turned on, the user can be sure of the discharge capacity state of the secondary battery 70 in real time. I can inform you.

Further, the battery state indicator 36 is composed of a battery figure A in the shape of a battery, and the number of bars B included in the battery figure A represents the state of the discharge capacity of the secondary battery 70 (preferably. Since the margin until the discharge capacity of the secondary battery reaches the limit value is displayed by the number of bars, any user can understand the state of the power supply battery at a glance and even unskilled users can charge the battery. This makes it possible to use (carry) this device with peace of mind at the worksite of resistance welding without any negligence in management.

However, the battery state indicator 3 of the above embodiment
It is not limited to 6 and various indicia or image patterns can be selected or used.

[0058]

As described above, according to the portable resistance welding measuring device of the present invention, useful monitor information can be given to the user regarding the state of the discharge capacity of the secondary battery incorporated as the power battery. In particular, the state of the discharge capacity of the secondary battery can be clearly and accurately known to the user at a glance. Therefore, it is possible for the user to use the device with confidence in the field of resistance welding and to improve the reliability in terms of production management.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external configuration of a portable resistance welding measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main configuration of a resistance welding measuring apparatus in the embodiment.

FIG. 3 is a front view showing an example of display screen contents of a display in the resistance welding measuring apparatus of the embodiment.

FIG. 4 is a diagram showing a circuit configuration of an internal power supply circuit included in the resistance welding measuring apparatus of the embodiment.

FIG. 5 is a diagram showing an example of a method of charging a secondary voltage built in the resistance welding measuring apparatus in the embodiment.

FIG. 6 is a diagram showing a discharge capacity load characteristic of a secondary voltage built in the resistance welding measuring apparatus in the embodiment.

FIG. 7 is a diagram schematically showing the content of a marker displayed on the screen for displaying the progress of the discharge capacity of the secondary voltage on the monitor in the embodiment.

[Explanation of symbols]

10 housing 12 display 14 keyboard 36 Battery status indicator 50 RAM 54 CPU 56 ROM 60 Display 64 Internal power supply circuit 70 secondary battery 72 Switching Regulator 74 Pre-charging circuit 76 Charge control circuit 78 Battery voltage monitor circuit 80 Charge current monitor circuit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G016 CB02 CB23 CB31 CC01 CC03                       CC04 CC05 CC06 CC07 CC12                       CC16 CC20 CC23 CC25 CC26                       CC27 CC28 CD04 CD09 CD14                       CE02 CE03 CE08 CE31                 5H030 AA08 AS11 FF41 FF44

Claims (6)

[Claims] 1. A built-in secondary battery is used to measure a predetermined welding condition in resistance welding using electric power generated by discharging the secondary battery, and the measured value of the welding condition is displayed on a display on an operation panel. In the portable resistance welding measuring device configured as described above, a battery voltage detecting unit that detects a voltage between the positive electrode and the negative electrode of the secondary battery, and a discharge load characteristic specific to the secondary battery and the battery voltage detecting unit detect the voltage. And a battery capacity state display means for displaying the state of the discharge capacity of the secondary battery on the display based on the battery voltage stored in the portable resistance welding measuring apparatus. 2. The monitor voltage setting means for dividing the discharge capacity of the secondary battery into a plurality of stages on the discharge load characteristic and setting the voltage at the passing point of each stage as a monitor voltage by the battery capacity state display means. Means for comparing the battery voltage detected by the battery voltage detection means with the monitoring voltage to determine which of the stages the current discharge capacity of the secondary battery corresponds to, the discharge A mark for identifying and displaying each stage of the capacity is set, and the mark corresponding to the corresponding stage discriminated by the discriminating means is used as the visual information indicating the progress state of the discharge capacity of the secondary battery stepwise. The portable resistance welding measuring apparatus according to claim 1, further comprising: a sign display unit for displaying on the display. 3. The portable resistance welding measuring device according to claim 2, wherein the mark has a figure in the shape of a battery. 4. The battery capacity status display means always displays the status of the discharge capacity of the secondary battery on the display while the power switch is turned on. The portable resistance welding measuring device according to any one of the above. 5. The battery capacity status display means displays, on the display, a margin for reaching a predetermined limit value as a status of the discharge capacity of the secondary battery. The portable resistance welding measuring device according to any one of the above. 6. The battery capacity status display means displays the status of the discharge capacity of the secondary battery at a predetermined position set in the screen area of the display. The portable resistance welding measuring device according to any one of the above.