JP3810474B2 - Soldering iron equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soldering iron device used when soldering an electronic component to a printed circuit board.
[0002]
[Prior art and problems to be solved by the invention]
Generally, a soldering iron device having a temperature setting function is a temperature control unit that feedback-controls energization to a heater that heats the tip so that the measured temperature of the tip detected by the temperature sensor is equal to the target temperature. Have In this case, the feedback control uses proportional integral differential control (PID control), that is, control including a proportional element (P element), an integral element (I element), and a differential element (D element) in a feedback loop. Control characteristics with little temperature deviation and excellent dynamic characteristics are realized.
[0003]
However, in such a soldering iron device using PID control, when the soldering operation which has been continuously performed is interrupted, the temperature of the tip is transiently overshooted due to a rapid reduction in load. For this reason, there is a problem that the soldering operation cannot be resumed until the tip temperature converges to the set temperature, resulting in poor work efficiency.
[0004]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a soldering iron device that can improve the working efficiency of soldering work.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, as a first means, a temperature setting means for inputting a set temperature of the tip, a temperature detecting means for detecting the temperature of the tip and outputting it as a measured temperature, In the soldering iron device comprising temperature control means for controlling energization to the heater that heats the tip based on the deviation of the measured temperature, the temperature control means controls energization to the heater according to the operation of the operation element. A means of switching between proportional integral derivative control and proportional control is employed.
[0006]
As the second means, in the first means, when the energization control to the heater is performed by proportional control, the temperature control means adopts means for offsetting the set temperature so as to cancel the steady temperature deviation.
[0007]
As a third means, in the first or second means, a means is used in which the temperature control means lowers the set temperature when it is determined that the use is interrupted for a certain time based on the measured temperature.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a soldering iron apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a circuit diagram showing the configuration of the present embodiment. In this figure, reference numeral 1 denotes a one-chip microcomputer (temperature control means), and ROM (read only memory), RAM (write / read memory), CPU (central processing unit), various input / output interfaces, etc. are contained in one chip. It is what was done.
[0009]
Reference numeral 2 denotes a tip, which includes a heater 3 that heats the tip 2 and a temperature sensor 4 that detects the temperature of the tip 2 and outputs it as a measured temperature. The one-chip microcomputer 1 performs PID control (proportional-integral-derivative control) or P-control (control) as described below for energization of the heater 3 based on a control program stored in the ROM and a set temperature and control constant described below. Proportional control).
[0010]
Reference numeral 5 denotes a power transformer, which supplies a commercial power source to a series circuit of the heater 3 and the thyristor 6 and a zero cross detector 7 by reducing the commercial power source to an AC voltage of 24 Vrms, for example. The zero cross detector 7 detects the zero cross position of the AC voltage input from the power transformer 5 and outputs it to the one-chip microcomputer 1. The thyristor 6 is ON / OFF controlled by the one-chip microcomputer 1 based on the output of the zero cross detector 7.
[0011]
The output of the power transformer 5 is input to the power circuit 8. The power supply circuit 8 rectifies the AC voltage input from the power transformer 5 and outputs a DC power supply voltage such as ± 5 V and +3 V, for example. On the other hand, the temperature detection signal output from the temperature sensor 4 is input to the amplifier 9, which amplifies the temperature detection signal and outputs it to one selection terminal of the multiplexer 10.
[0012]
On the other hand, the output of the thermistor 12 is amplified by the amplifier 11 and input to the other selection terminal of the multiplexer 10. The multiplexer 10 outputs the output of the temperature sensor 4 based on the output of the one-chip microcomputer 1. Alternatively, the output of the thermistor 12 is alternatively output to an A / D converter (analog / digital converter) 13. The A / D converter 13 converts an input signal that is an analog signal into a digital signal and outputs the digital signal to the one-chip microcomputer 1.
[0013]
Reference numeral 14 denotes a switch, which controls the volume of the buzzer 15 by switching the power supply voltage supplied to the buzzer 15 to either + 5V or + 3V based on the output of the one-chip microcomputer 1. The buzzer 15 is controlled in sound generation based on a signal input from the one-chip microcomputer 1 through the buffer amplifier 16.
[0014]
Reference numeral 17 denotes an operation panel (operator), which includes a plurality of indicators 18 and operation switches 19. Each operation terminal of the display 18 is connected to the one-chip microcomputer 1 through the buffer 20, and the common terminal is connected to the collector terminal of the transistor 21. Each base terminal of the transistor 21 is connected to the one-chip microcomputer 1, and, for example, a power supply voltage of +5 V is supplied to the common terminal of each display 18 based on the output of the one-chip microcomputer 1. The operation switch 19 is interposed between the collector terminals and the one-chip microcomputer 1 so that the operation is input to the one-chip microcomputer 1.
[0015]
FIG. 2 is a plan view showing the configuration of the operation panel 17. In this figure, reference numeral 19a denotes a numerical value input switch for inputting the set temperature of the tip 2, etc., and the set temperature input from the numerical value input switch 19a is displayed on the set numerical value display 18a. 19b is a display digit shift switch for operating the digit shift of the set temperature displayed on the set numerical display 18a, 19c is a parameter changeover switch for switching the input mode of the numeric input switch 19a, and 19d is a holding state of the set temperature (key lock). A key lock switch 18b for switching between a set state) and a release state (key lock release state) is a key lock setting lamp that lights up when the key lock is set.
[0016]
Further, reference numeral 18c denotes a measurement temperature indicator that displays the measurement temperature output from the temperature sensor 4, 18d denotes a heater energization indicator that is turned on when the heater 3 is energized, and 18e denotes the measured temperature by the numerical value input switch 19a. An alarm lamp that lights when the set range is deviated or is within the set range, 18f is an auto-tuning lamp that blinks when the operation mode of the soldering iron device is in the auto-tuning mode, and 18g is an operation mode that is in the sleep mode. This is a sleep setting lamp that is lit in the case.
[0017]
The soldering iron device has a switching mode of the control method of the heater 3 as one of the input modes, and the temperature of either the PID control method or the P control method is operated by operating the parameter changeover switch 19c. The control method can be selected. Further, when a state that is not used for a certain period of time is detected based on the measured temperature, the power saving state (set temperature (sleep set temperature)) lower than the set temperature (normal set temperature) of the tip 2 in the normal use state ( The sleep lamp 18h is turned on when shifting to the sleep state.
[0018]
In FIG. 1, reference numeral 22 denotes an oscillation circuit that generates a basic clock for the one-chip microcomputer 1. Reference numeral 23 denotes a reset switch for initializing the one-chip microcomputer 1.
[0019]
Reference numeral 24 denotes an EEPROM (electrically writable / erasable memory), which stores, for example, a proportional constant (P1), an integral constant and a differential constant in a PID control system (proportional integral differential control system) as a control constant, and a P control system. The proportionality constant (P2) in (proportional control system) is stored. The EEPROM 24 is also configured to store the key lock setting state, the key lock release state, the control method of the heater 3 when the power is turned off, and the like.
[0020]
Next, the tip temperature control operation will be described with reference to the flowchart shown in FIG. 3 and the temperature change characteristic of the tip 2 shown in FIG.
When the soldering iron device is used, the normal set temperature and the sleep set temperature as the set temperature of the tip 2 are stored in the EEPROM 24 in advance.
[0021]
When the power is turned on, the one-chip microcomputer 1 performs an initial setting related to the temperature control of the tip 2 (step S1). That is, various setting values when the power is last turned off are read from the EEPROM 24 and initialized. In this case, when the power was turned off in the previous PID control state, the proportional constant (P1), integral constant, differential constant, and the above normal set temperature and sleep set temperature related to PID control are initialized. When the power is turned off last time in the control state, the proportionality constant (P2) related to P control and the normal set temperature and sleep set temperature at that time are initialized.
The following explanation will be given on the assumption that the proportionality constant (P1), integral constant and differential constant relating to PID control are initially set.
[0022]
When the initial setting is performed in this way, the heater 3 that heats the tip 2 is PID-controlled based on the difference between the normal set temperature and the measured temperature detected by the temperature sensor 4. That is, the heater 3 has its control characteristics defined by the proportionality constant (P1), integral constant, and differential constant related to the PID control, and the energization is controlled (step S2).
[0023]
Subsequently, it is determined whether or not the initial mode (initialization mode for various settings) or the resetting of the normal setting temperature and the sleep setting temperature is instructed by the operation of the parameter selector switch 19c (step S3). If this determination is “NO”, the temperature control of the tip 2 is performed by performing PID control of the heater 3 in step S2.
[0024]
On the other hand, if the determination in step S3 is “YES”, it is determined again whether or not the initial mode has been instructed by executing the process in step S4. If this determination is “NO”, for example, the normal set temperature or sleep set temperature is reset to the value input from the numerical value input switch 19a in step S5, and the normal set temperature reset in step S5. Alternatively, the heater 3 is PID controlled based on the sleep set temperature.
[0025]
When this determination is “YES”, that is, when the initial mode is instructed, it is determined in step S6 whether or not there has been an instruction to switch between the PID control method and the P control method by operating the parameter selector switch 19c. When “PID” is instructed, the process of step S7 is executed. When “P” is instructed, the process of step S8 is executed.
[0026]
For example, when “PID” is instructed, the control constant for PID control, that is, the proportionality constant (P1), the integral constant, and the differential constant are reset in step S7. Based on the control constant, the temperature control of the tip 2 is performed in step S2.
[0027]
On the other hand, when “P” is instructed, a control constant for P control, that is, a proportionality constant (P2) is set in step S8. When the heater 3 is controlled by the P control, an offset with respect to the normal set temperature is generated in the temperature in the steady state, and the offset is corrected (step S9).
[0028]
Since the offset correction amount differs depending on the heat capacity of the heater 3 and the temperature characteristics with respect to the energization of the heater 3, the offset correction amount of the soldering iron device is determined in advance in consideration of these factors and stored in the ROM. The The energization of the heater 3 is controlled so that the temperature of the tip 2 in a steady state is set to the normal set temperature by setting the temperature obtained by adding the correction amount to the normal set temperature as the target temperature.
[0029]
According to such a soldering iron device, the operator can select either the PID control method or the P control method as the control method of the heater 3 according to the content of the soldering work.
[0030]
Here, FIG. 4 shows the change characteristics of the tip temperature in such PID control and P control. As shown in this figure, in the case of PID control, the temperature of the tip 2 during work is controlled so as to be a normal set temperature with relatively good follow-up, but overshoot occurs when the work is interrupted. Jumps above the normal set temperature. On the other hand, in the case of the P control, the followability of the temperature of the tip 2 during work is not good, but when the work is interrupted, it converges to the normal set temperature without causing overshoot.
[0031]
Therefore, in the case of PID control, it takes time until the temperature of the tip 2 converges to the normal set temperature when the operation is interrupted. Therefore, soldering in a state where the temperature of the tip 2 is equal to or higher than the normal set temperature. In the case of a soldering operation that is not preferable, the next operation can be quickly performed by selecting the P control method.
When the use stop state is detected continuously for a certain time after the work is interrupted, the operation mode of the soldering iron device shifts to the sleep state, and the heater is set so that the temperature of the tip 2 becomes the sleep set temperature. 3 is controlled.
[0032]
In the above embodiment, the temperature of the tip 2 is controlled by the control program. However, the control algorithm is not limited to the above flowchart, and the present invention is software-like. The above-described control may be realized by hardware means without being limited to such means.
[0033]
【The invention's effect】
As described above, the soldering iron device according to the present invention has the following effects.
(1) Since the temperature control means is configured to switch the energization control to the heater between proportional integral differential control and proportional control according to the operation of the operation element, proportional integral differential control and proportional control according to the contents of the soldering work. By selecting the proportional control, the work efficiency of the soldering work can be improved. For example, in proportional-integral-derivative control, when the soldering operation is interrupted, it takes time for the tip temperature to jump above the target temperature and converge to the target temperature. In the case of soldering work in which soldering is not preferable, workability is poor. However, in such a case, the temperature of the tip can be prevented from jumping by placing the soldering iron device in a proportional control state, so that the workability of the soldering operation can be improved.
(2) When the heater is proportionally controlled, the set temperature is offset so as to cancel out the steady temperature deviation. Therefore, the effect of the steady temperature deviation inevitably associated with the proportional control is eliminated, and the tip temperature becomes the set temperature. Can be controlled.
(3) Since the set temperature is lowered when use interruption over a certain period of time is determined based on the measured temperature, it is possible to suppress power consumption.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a soldering iron apparatus according to the present invention.
FIG. 2 is a plan view showing a configuration example of an operation panel in the soldering iron apparatus according to the present invention.
FIG. 3 is a flowchart showing the operation of the soldering iron apparatus according to the present invention.
FIG. 4 is a graph showing a change characteristic of a tip temperature of a soldering iron device according to the present invention.
[Explanation of symbols]
1 One-chip microcomputer 2 Tip 3 Heater 4 Temperature sensor 5 Power transformer 6 Thyristor 7 Zero cross detector 8 Power circuit 9, 11 Amplifier 10 Multiplexer 12 Thermistor 13 A / D converter 14 Switch 15 Buzzer 16 Buffer amplifier 17 Operation panel 18 Display 19 Operation switch 20 Buffer 21 Transistor 22 Oscillation circuit 23 Reset switch 24 EEPROM

Claims (3)

To temperature setting means for inputting the set temperature of the tip, temperature detection means for detecting the tip temperature and outputting it as a measured temperature, and a heater for heating the tip based on the deviation of the measured temperature with respect to the set temperature In a soldering iron device comprising a temperature control means for controlling energization of
An EEPROM for storing whether the control method of the temperature control means when the power is turned off is proportional-integral-derivative control or proportional control;
When the power is turned on , the temperature control means performs the energization control to the heater by the same control method as when the power is turned off based on the EEPROM, and switches the control method according to the operation of the operation element. Soldering iron device characterized by   2. The soldering iron device according to claim 1, wherein when the energization control to the heater is performed by proportional control, the temperature control means offsets the set temperature so as to cancel the steady temperature deviation. 3. The soldering iron device according to claim 1, wherein the temperature control means reduces the set temperature when use interruption over a predetermined time is determined based on an increase in the measured temperature. .

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