JP2688821B2 - Control circuit function inspection method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the function of a control circuit by computer processing, and more particularly to an inspecting method suitable for inspecting the function of a control circuit used for controlling a water heater. It is about.

2. Description of the Related Art In recent years, a water heater has also been equipped with a control circuit board including a microcomputer for controlling its functions.
In a water heater, hot water supplied from the hot water heater is supplied to a bath, a shower, a washroom, a kitchen, and the like, and directly touches a human skin. Therefore, if hot water is suddenly ejected from the water heater due to a failure or the like, there is a risk of burns and the like. For this reason, the control circuit board mounted on the water heater and controlling its function must be strictly inspected before the product is shipped so that such a failure does not occur. For this purpose, in addition to the in-circuit check for each electrical circuit element such as the IC and the like that constitute the control circuit, such as resistors and capacitors, and the microcomputer that constitutes the microcomputer, etc., the inspection of various control functions of the control circuit Function check to perform In the control circuit of the water heater, the inspection items that must be inspected in this function check are, for example, fan safety time, lockout postpurge, prepurge time, IG safety time, slow ignition time, postpurge time, non-ignition. There are a large number of items including abnormalities, accidental misfires, hot water supply thermistors, and high limit operation abnormalities. However, conventionally,
Since the timer and the like had a hardware configuration like a CR configuration circuit, it was necessary to inspect all of these inspection items in the functional inspection method.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional function inspection method for a control circuit, all of a great number of inspection items are inspected, and therefore the inspection time for that purpose is very long.
It took 10 minutes for each control circuit. Therefore, in order to perform this functional inspection in a mass production line, many inspection facilities were needed.

An object of the present invention is to provide a method for inspecting the function of a control circuit, which can solve the above conventional problems.

According to the present invention, in a method for inspecting a function of a control circuit by processing of a computer, the computer is associated with any one of a plurality of functions of the control circuit corresponding to a control amount. Has at least one common function to be executed, and performs measurement and inspection only on a representative inspection item among the inspection items of the plurality of functions, and determines whether the hardware circuit of the computer and the common function are normal. It is characterized in that it is unnecessary to check other inspection items among the inspection items of the plurality of functions by checking whether or not.

Next, the present invention will be described in more detail with reference to the accompanying drawings.

First, before describing the embodiments of the present invention, the basic concept of the present invention will be described. The present inventor has realized that a control circuit board mounted on a recent water heater controls various control circuit functions by a single microcomputer mounted on the board. We paid attention to the fact that it is processed by the function of the software shared by. Then, the inventor of the present invention, in the functional inspection of the control circuit by the processing of such a computer, the control amount (for example, a temporal element).
Among the inspection items of the plurality of functions of the control circuit corresponding to, the representative inspection item (for example, the item having the shortest inspection time) is measured, and the measurement result shows that the desired control function is fulfilled. If so, the hardware and software features of the computer (eg,
The present invention was made based on such a basic idea, paying attention to the fact that the timer function) is normal, and if so, the other control functions can also be judged to be normal.

FIG. 1 of the accompanying drawings is a schematic block diagram for explaining an embodiment of an inspection apparatus for carrying out the function inspection method of the present invention. In FIG. 1, reference numeral 100 indicates a control board mounted on the water heater, and reference numeral 200 indicates an inspection apparatus as an embodiment of the present invention for inspecting the control function of the control board 100. Shows. Hot water heater control board 100
Is a microcomputer 110, fan circuit 120, igniter circuit 130, frame sensor circuit 140, solenoid valve circuit
It has a 150, a thermistor circuit 160, a water flow switch circuit 170 and the like. The microcomputer 110 fulfills a timer circuit function 111 commonly used to control the fan safety time, lockout post purge, prepurge time, slow ignition time, etc. Alarm circuit function commonly used to alarm hot water supply thermistor abnormality, high limit abnormality, etc. 112
Is programmed to fulfill the fan circuit 12
0, igniter circuit 130, frame sensor circuit 140,
The solenoid valve circuit 150, the thermistor circuit 160, the water flow switch circuit 170, etc. are controlled to control various functions of the water heater.

The inspection device 200 includes a fan rotation speed circuit 201, an AC / DC conversion circuit 202, a frame relay circuit 203, an AC / DC conversion circuit 204, a thermistor open circuit 205, a thermistor short circuit 206, a PB port set circuit 207, and a PA port. Input circuit 20
8, water switch relay circuit 209, pre-purge time circuit
210, a slow ignition time circuit 211 and an alarm discrimination circuit 212 are provided.

Next, the operation of this inspection device 200 will be described. First, the inspection device 200 has a pre-purge time (1.5 seconds) and a slow ignition time (1.5 seconds), which are the items having the shortest inspection time among the inspection items of the plurality of functions of the control circuit of the water heater control board 100. To check whether the timer circuit function of the microcomputer 110 is normal, and also to check the hot water supply thermistor for abnormalities.
By checking whether or not the alarm circuit function of 110 is normal, the function of the entire control circuit of the water heater control board 100 is tested.

As shown in the flowchart of FIG. 2, for the pre-purge time, in step 301, the water flow switch relay circuit 209 is operated to instruct the water flow switch circuit 170 to turn on the hot water supply water flow switch and the fan circuit 12
In response to the signal from 0, the fan rotation speed circuit 201 sends a start signal to the prepurge time circuit 210 when the rotation speed of the fan exceeds 2000 RPM which is the ignition rotation speed, and at the same time, in step 303, the microcomputer. 110 timer software works. In step 304, when the AC / DC conversion circuit 202 receives the igniter signal from the igniter circuit 130 and detects that the igniter signal is on, the end signal is input to the prepurge time circuit 210. Prepurge time circuit 2
10 determines the time between the start signal and the end signal input thereto as the prepurge time, and if this prepurge time is a predetermined time, for example, 1.5 seconds, the timer circuit function of the microcomputer 110. Is working correctly. Regarding the slow ignition time, the flame relay circuit 203 gives an instruction to the flame sensor circuit 140 as shown in step 305 of the flowchart of FIG. Input to the time circuit 211. At the same time, in step 306, the timer software of the microcomputer 110 works. In step 307, for example, from the solenoid valve circuit 150,
When the AC / DC conversion circuit 204 receives the signal indicating the transition to the 12-stroke combustion and detects that the solenoid valve is on, the end signal is input to the slow ignition time circuit 211. The slow ignition time circuit 211 determines the time between the start signal and the end signal input thereto as the slow ignition time, and if the slow ignition time is a predetermined time, for example, 1.5 seconds, the microcomputer 110 It is assumed that the timer circuit function of is functioning properly.

As for the hot water supply thermistor abnormality, as shown in the flowchart of FIG. 3, first, at step 401, the thermistor open circuit 205 issues a thermistor open instruction to the thermistor circuit 160, and at step 403, at the PB port. Set circuit 207 is microcomputer 110
Output the set signal to the PB port of. At step 404, the output from the PA port of the microcomputer 110 is P
Input to the A port input circuit 208. At step 405,
The alarm discriminating circuit 212 discriminates whether or not the output of the PA port of the microcomputer 110 from the PA port input circuit 208 is "4" indicating a thermistor open alarm, and if so, the alarm circuit function of the microcomputer 110. Is working correctly. Further, in step 402, the thermistor short circuit 206 issues a thermistor short instruction to the thermistor circuit 160, and in step 403, the PB port set circuit 207 causes the microcomputer 110 to operate.
Output the set signal to the PB port of. At step 404, the output from the PA port of the microcomputer 110 is P
Input to the A port input circuit 208. At step 405,
The alarm discriminating circuit 212 discriminates whether or not the output of the PA port of the microcomputer 110 from the PA port input circuit 208 is "4" indicating the thermistor short circuit alarm, and if so, the alarm circuit function of the microcomputer 110. Is working correctly.

Such a function test requires a very short time, for example, about 2 minutes, as compared with testing all the functions of the control circuit.

In addition, in the above-mentioned embodiment, it was applied to the functional inspection of the control circuit of the control board of the water heater, the present invention,
The present invention is not limited to this, and the same effect can be obtained by applying to the function inspection of the control circuit by the same computer processing.

Effects of the Invention According to the function inspection method of the present invention, the following effects can be obtained.

(1) Among the inspection items of the plurality of functions of the control circuit corresponding to the control amount, it is sufficient to perform the measurement inspection on a representative inspection item, which enables an accurate inspection and significantly shortens the inspection time. Therefore, the manufacturing cost can be reduced.

(2) Since the inspection time is short, the number of inspection devices can be small, the equipment cost can be significantly reduced, and the fluctuation of the number of control circuits to be inspected can be flexibly dealt with.

(3) Since it is not necessary to develop software for inspection items that require a long time for inspection, it is possible to reduce the labor and the development time for software development.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram for explaining an embodiment of an inspection apparatus for carrying out the function inspection method of the present invention, and FIG.
The figure which shows the flowchart for demonstrating the inspection of the timer circuit function performed in the inspection apparatus of FIG. 1, FIG. 3 is the flowchart for demonstrating the inspection of the alarm circuit function performed in the inspection apparatus of FIG. FIG. 100 …… hot water heater control board, 111 …… timer circuit function, 112 …… alarm circuit function, 120 …… fan circuit, 130 …… igniter circuit, 140 …… frame sensor circuit, 150 …… solenoid valve circuit, 160… … Thermistor circuit, 170 …… Water flow switch circuit, 200 …… Inspection device, 201 …… Fan rotation speed circuit, 202 …… AC / DC conversion circuit, 203 …… Frame relay circuit, 204 …… AC / DC conversion circuit , 205 …… thermistor open circuit, 206 …… thermistor short circuit, 207 …… PB port set circuit, 208 …… PA port input circuit, 209 …… water flow switch relay circuit, 210 …… pre-purge time circuit, 211 …… Slow ignition time circuit, 212 …… Alarm discrimination circuit.

Claims (3)

(57) [Claims] 1. A method of inspecting a function of a control circuit by processing of a computer, wherein the computer carries out at least one common operation that is performed when any of a plurality of functions of the control circuit corresponding to a control amount is executed. Having a function, among the inspection items of the plurality of functions, a measurement inspection is performed only on a representative inspection item, and by checking whether or not the hardware circuit of the computer and the common function are normal, A method of inspecting a function of a control circuit, which does not require checking of other inspection items among inspection items of a plurality of functions. 2. The function inspection method for a control circuit according to claim 1, wherein the common function is a timer function. 3. The function inspection method for a control circuit according to claim 1, wherein the common function is an alarm function.