Note: Descriptions are shown in the official language in which they were submitted.
1 The present invention relates to a heating
apparatus with a simplified operating panel.
The remarkable progress of the semic~nductor
technology has brought about numerous technological
re~clutions in the field of home appliances. High-
performance home appliances which involve too large-
scale system to be commercialized by the prior art
discrete circuit configurations have recently been
supplied to the market successively thanks to the
reduced cost of the microcomputer, LSI, large-capacity
memory and the like.
High~performance products with a high added
value, however, ~enerally include an operating section
with a number of operating keys complicating the
15~ handling procedures, resulting in an increased risk of
erroneous operatlon of the system due to personal fac-
;tors of users~ operating er~ors. ~Especially, the
heating apparatuses~are mainly used by ordlnary housewi-
ves~ who, unlike audio set manias, are not interested in
a~compl1cated~operation w~ith~multi-functions. Further,
a misuse of a hea~ting apparatus often causes a heating
ailure of the food to be cooked and in an extreme case
may lead~to~an accldent such~as a fire in and out of the
heating chamber.
`
;
- ~' - ' ~ :
: '. ; '`
- ` "
1 In addition, a system comprised of electronic
circuits is liable to be operated erroneously by noies.
Factors causing malfunctions of an electronic device are
so various that they include spike noises from the power
line, radiation noises coming directly into the system,
and static electricity. The most adverse malfunction of
the heating apparatus which is caused by such physical
factors is the malfunction concerning the control of the
heating means. It sometimes actually happens that an
undesired heating process is started or the heating
still continues after the lapse of a predetermined
heating time. These malfunctions, like the above-
mentioned malfunctions due to personal factors~ have a
grea~ risk o causing a loss to human life or property
through fire or burns~
Therefore, the most important requirement in
system safety design for the heating apparatus including
electronic circuits is to prevent the two great personal
and physical errors of misuse and malfunctions and to
; ~ 20 quickly inform the user of any case of such misuse or
~malunctions.
~ The object of the present invention is to pro-
vide a safety devlce using a voice synthesizer ~or the
~:
heatlng apparatus for preventlng the two errors of
2~ misuse and malfunctions and informing the user quickly
; of any case of such problemsO
As a means of achieving this o~ject, a voice
~ - 2 -
''`'' .
::
1 synthesizing techni~ue is used, and by making use of the
features mentioned below of the human voice (language),
the above-mentioned object is realized without fail. Of
all the features of the voice (language), three are uti-
lized by the presen~ invention. First, an informationis transmitted even to the user distant from the appara-
tus. Secondly, the information is transmitted directly.
Thirdly, the information transmitted is understandable
even by illiterate persons or infants. These three
features work very effectively to prevent such emergency
cases as misuse and malfunctions.
According to the present invention, a heating
apparatus comprises a heating chamber of housing an
object to be heated; heating means for supplying heat to
said heating chamber, input means such as a keyboard for
ordering a command on a desired operation; a main
control section for producing a control signal in
response to a command from said input means; a time
control section controlled by the control signal from
said main control section for supplying power to said
heating means; output switching means for changing the
output of said heating means; a RAM for storing sequen-
:: :
tially any data applied thereto~successively includingthe output and the heating time from said input means; a
voice memory for storing a plurality of voice data; a
voice synthsizer section for reading out a selected
voiFe data from said voice memory and synthesi ing the
- 3 -
~, :
-.
:
!9
.
'
,
~ 3~ ~ ~
1 same into a voice; means for producing an address data
for reading out voice data in said voice memory; and
said input means including a program recall key, said
main control section providing at least one o~ display
data and a voice select signal corresponding to the
input data for controlling said heating means, upon
depressing said program recall key.
The above and other ob~ects, features and
advantages will be made apparent by the detailed
descriptlon taken in conjunction with the accompanylng
drawings, in which.
Fig. 1 is a perspective view showing the body
of a conventional heating apparatus;
Fig. 2 is a diagram showing in detail a con~
ventional operating panel;
Figs. 3a to 3e show operating steps and
displays for programmed heating;
Fig. 4 is a diagram showing in detail an
operating panel according to an embodiment of the pre-
sent invention;
Figs. 5a to 5d show an example of a program
recall;
Fig. 6 is a block diagram showing a con-
figuration of the present invention;
25Fig. 7 is a diagram showing a circuit
embodylng the pre~ent invention;
Fig. 8 is a timing chart for a synthesizer;
l Fig. 9 is a sectional view of a heating
apparatus; and
Fig 10 is a flowchart of a control program.
The configuration of the prsent invention for
attaining the above-mentioned object is generally
divided into the four items including a simple operating
panel which is difficult to misuse, a program recall
function to make sure that there is no error in the
course of programming of a set stage heating, a function
to report the heating progress detected by a sensor
means or a timer means at the starting time of heating,
and means for detecting a fault of the sensor means or
timer means, taking a predetermined trouble-shooting
action and giving an alarm on the error.
These items will be described in detail one by
one. First, explanation~will be made of the simple
;construction of the operating panel. Several keys
~ , :
having relatively similar functions on the operating
panel are grauped positively i~nto a single multi-command
key. By doing so,~the operating panel configuration is
simplified.~; The multi-command key performs different
functions~ each~time lt is depressed according to the
conditions~prevailing, and;therefore the convenience of
operating~is~not greatly 1mproved. In order to i prove
25~ the convenience of~operating the~refor~, the conditions
are ~identl~ied hy the system and the user is informed of
; a select~ed functlon or the next operating step through a
. ~ . .
. , . .. ,
.. . . .
1 synthesized voice, thus providing an apparatus with a
simple and conveniently-operated operating panel.
Explanation will now be made with reference to the
accompanying drawings.
Conventional heating apparatuses such as a
microwave oven or electric range having a digital
control section generally include an operating panel
conf iguration as shown in Figs. 1 and 2. Fig. 1 is a
perspective view of the body of a heating apparatus
having such an operating panel and Fig. 2 is a diagram
showing in detail the operating panel. In these
drawings, a door 2 free to open and close and an
operating panel 3 are provided on the front of the body
lo A keyboard 4 and a display section 5 are arranged on
the operating panel 3. Various commands or instructions
of the user are applied to a control system through the
keyboard 4. In this way, the conventional operating
panel includes more keys with an increase in functions,
and these keys must be operated in a predetermined order
20; for effective data input. A wrong key is often
depressed or keys are depressed in a wrong order
re~ulting in an~erroneous setting.
or~example, the two-stage heating using a
timer, though very useful for heating the food success-
25~ fully, involves compllcated program steps hard tounderstand, often causing a cookl~ng failure by the user.
This two-stage heating by a timer will be described
6 -
.
., .
: :
. ,
- . . ~,
l below.
Xey operations and displays are shown in Figs.
3a to 3e. The time is ordinarily indicated on the
display section 5. The timer mode is changed by
depressing the power key 8, so that "00.00" appears on
the numeral display section 15, and "STAGE l" of the
stage indicator 17 is lit. Depression of the power
le~el key 7 (DEF), the output "D~FROST" is preset, and
the DEF status of the power indicator 16 is lito (Fig.
3a)
Upon depression of the time key 6 and the
numeral keys 7, a heating time is preset. If the key
TIME and "2", "6", "0" and "0" of the numeral keys 7 are
depre~sed in that order, ~or instance, the time of 26
minutes is entered and "26.00" appears on the numeral
display section 15. (Fig. 3b)
Upon subsequent depression of the POWER key
and the power level key "l (HIGH ) ", it iS accepted as an
output for the second stage. The numeral display sec-
20 ~tion 15 returns to ~ioo.oo" and STAGE Z of the powerindicator 16 and the ~IGH status of the power indicator
16 are lit (Fig. 3c).
.
As in the first stage, the TIME key and the
numeral keys ~3~ 3~ and "0" are depressed to store the
heating time of 3 minutes~and 30 seconds, so that "3.30"
appears on the numeral display section 15 (Fig. 3d).
It will be seen that in the stage heating, a
7 -
~ .
, ~ ,
, `~ ,
31 ~ 3~k~
1 number of keys must be operated, data are displayed on
different display sections successively, and also the
keys must be operated in accordance with a predetermined
rule, thus complicatinq the operation of the apparatus.
After presetting the data for a two-stage
programmed heating, the heating is started by depression
of the START key 13. The first input "DEFROST: 26 min~"
is executed, followed by the execution of the "HIGH: 3
min 30 sec~' of the second stage~ At this time, the
display section 5 may flicker the "STAGE 1" and "DEF" in
execution while continuously lighting the remaining
heating stage, so that the stage indicator 17 and the
power indicator 16 may display the whole of the preset
program, but the numeral display section 15 can display
only the heating time of the stage in execution. (Fig.
3e) In other words, it is impossible to confirm the
heating time of th~ second stage while the first stage
is being executed.
The same can be said of the programs of Figs.
3a to 3d. Once the mode of Fig. 3c is entered, the data
of the preset first stage cannot be identified. This
problem becomes more serious with the increase of stages
to 3 and 4 than the ~ stage sequence of heating as in
the embodiment under consideration. Because of this
irrevocability, the programming of the stage heating
must~be formed very care fully and has no room for
allowance.
:
-- 8
.
..
1 As mentioned above, in the stage heating use-
ful for the heating apparatus~ the user is liable to
commit a misuse in setting. If the cooking is started
with an erroneous setting, it naturally fails and in an
extreme case the food to be cooked may start a fire
following carbonization. This is a second problem to be
solved.
The operating panel according to an embodiment
of the present invention is shown in detail in Fig. 4.
10 This operating panel solves the above-mentioned two
great problems by a simple operating panel construction
which is difficult to misuse and a program recall func-
tion capable of checking an error of a set heating
program. The construction of the operating panel
according to the present invention will be described
below with reference to the drawings. A display section
5, a numeral key 7 doubling as an output level setting,
and a START key 13 completely identical to those
included in a conventional apparatus are provided~
These keys have the same functions as the counterparts
;~ of the conventional apparatus, so that the display sec-
tion 5 has the same display functions as the conven-
tional apparatus.
On the other hand, the CLOCK/ADJUST key 18
have combined functions of the conventional CLOCK key 10
and the ADJUST key 11. When this key is depressed for
time indication, the system enters an adjust mode, and
., ,
.
: :. : ' ;
- , ~ ' ;
.' ' . .
~ 3~
1 the selected mode name is issued to the user through the
speaker slit 19 in the form of a synthesized voice
"ADJUST".
"ADJUST"
"CLOCK 1l
__ ~ 7
CLOCK ~
( ~ indicates displayed data, and ~ key operation)
The time is set in the same steps as in the conventional
apparatusc After the time is set r the second
CLOCX/ADJUST key synthesizes the voice "CLOCK" meaning
that the setting is completed and the clocking operation
: starts. In place of ~ADJUST"~ the next operating step
may be notified. Specifically, "SELECT TIME" may be
: issued and thus the user is required to set the time by
: 20 the numeral key 7.
~ ~ : : If the CLOCKjADJUST key is depressed for other
:~ than time indication, the clock mode is entered and the
time is~indicatedO With the release of this mode, the
~:~ indication is restored.
~ "CLOCK" "TEMP"
~ /ADJ ] ~:1
( Rele~ase
: ~ - 1 0 -
': : - ,
~ : '
i9~
l At the time of release, the previous mode name such as
"TEMP" is issued.
As seen from above, the CLOCK/ADJUST key 18 is
a multi-command key having dual functions of the prior
art CLOCK key 10 and the DJUST key ll. Individual func-
tions selected are notified orally to the user directly,
thus greatly reducing the risk of misuse of the
apparatus.
Next, the function key 20 will be described.
This key has three combined functions of the conven-
tional TIME key 6, the POWER key 8 and the TEMP key 9,
any of which can be selected by tapping. Specifically,
one tap selects the TIME function, two taps the POWER
function, and three taps the TEMP function. An example
of setting the output and the heating time by this func-
tion key will be shown below.
20 ~ "TIME" ~ "POWER" "WARM"
"TEMP" "TIME"
:: ,
: : :
~ ~ ~25
-~ "START, STAGEl, WARM,
~ 26 MIN"
~"'" :~ :
':
.
. ~ : : .
.. .
1 The function thus selected is orally announced
in the words "TIME", "POWE~" or "TEMP". Thus the func-
tion key 20, inspite of being a multi-command key of
triple functions, has no operating complexity. Rather,
it has three functions of similar keys combined into
onQ~ so that the operating panel 3 is simplified and
gives no crowded appearance to the userO ~urther, when
a numeral key 7 is ued as an output level key/ the out-
put level is orally announced in such specific words as
"warm", thereby facilitating the operation of the
numeral keys 7 making up multi-command keys. Upon
depression of the start key 13~ a hating pattern such as
"START, STAGE 1, ~ARM, 26 MIN" is a~ain orally announced
~sking a renewed check of any programming error.
The temperature is set by the numeral keys 7
after selection of the TEMP mode by the function key 20
as in the conventional way.
The STOP/RESET key 21 is also a multi-command
key having the program clear function of the conven-
~;20 tional RESET key 12 and the heating suspension function
; of the STOP key 14 at the same time. If this key is
depressed during a programming, the programmed data are
cleared with the announcement of "RESET" and a ti~e
indication is restored. If the key 21 is depressed
during heating, on the other hand, the heating is
;~ suspended temporarily with the announcement of "STOP".
Now assume that a two-stage sequence heating
- 12 -
,
.
'' . , ~:
~ 3 ~
1 of "DEFROST, 26 MIN, HIGH, 3 MIN 30 SEC" is programmed
and the heating is started according to the above-
mentioned steps. The data indicated in the display sec-
tion 5 at this time are as shown in Fig. 5a.
Specifically, STAGE 1 is flickered indicating the
execution; STAGE 2 is continuously lit indicating a two-
stage sequence heating; RUN is lit indicating the
heating: DEF flickers indicating an execution output;
HIGH is lit indicating the power of the second stage
programmed; and 25 MIN 58 SEC is lit indicating the
residual heating time of the first stageO This residual
heating time is decremented by every second.
If tl~e PROGRAM RECALL key 22 is depressed
again to reche,ck the data on the programmed sequence
heating, the indication in the display section 5 changes
to that of Fig. 5b indicating the residual heating time
and power of the first stage. At the same time, a
synthesized voice "STAGE 1, DEFROST, 26 MIN" is
announced from the slits 19. As a result, the heating
20 ~pattern of the irst stage, together with the setting
and the;residual time are communicated simultaneously
both visually and orally without fail.
When a key is depressed, the eye line of the
user is generally directed toward the particular key and
` .
therefore the display section 5 cannot be viewed at the
sa~me time. This shortcomlng~ i5 effectively overcome by
aural communication through a synthesized voice.
- 13 _
..... .
The announcement of the first stage is automatically
followed by the announcement of the second stage. (Fig. 5c)
Speci~ically, the power and heating time of the second stage
are displayed simultaneously, while at the same time syn-
thesizing and announcing the words "STAGE 2, HIGH, 3 MIN 30SEC".
If the third stage is incorporated, the heating
pattern of the third stage is announced following Fig. 5c.
lQ In this way, a series of heating process~s are called
successively by the PROGRAM RECA~L key 22. Vpon completion of
the series of recall announcements, the indication returns
to Fig. 5d, thus restoring the total indication of the status
and the residual heating time of the first stage.
- As an alternative, the program recall key may be
so constructed as to recall one stage by one tap and restore
the original indication on release. As another alternative,
each stage may be recalled as in the previous case and the
2Q key released to stop with the particular stage indicated.
These constructions make possible correction beyond a stage.
Unlike in this embodiment in which the program is recalled
during heating, the recall is of course possible during
programming. Also, the voice announcement may be limited
to the stage numher, and the data for each stage may be
; checked by the display section.
A circuit configuration for realizing the pre-
3Q
:: :
;:
: .
,, . . . ~
~ ~ 14 -
~ .. ~. .
,
3~ ~ ~
sent lnventlon wlll be descrl~ed below. A ~lock diagram
of the present invention and an example of a specific
circuit configuration thereof are shown in Figs. 6 and 7
respectively.
Explanation will be made of the relation bet-
ween the configuration of the operatin~ panel and the
control system with reference to Figs. 6 and 7. At the
same time, the heating progress announcement function
and the error announcement function making up the third
and fourth features of the present invention respec-
tively will also be described.
The input signal taken into the controller 24
in synchronism with a strobe signal thereof by way of
input means 23 such as the keyboard 4 is decoded by the
controller 24 and accepted as an input command, and
stored in the RAM of the memory 25. Then the controller
: 24 produces a predetermined control signal thereby to
control the output. In order to orally announce the
function representing the operation executed, the
2~:controller 24 produces a predetermined volce select
signal to the address selector section 26. In response
to:this signal, the address selector section 26 applies
~: , : :
; an address~signal to the voice memory 27, so that the
voice data is read out of the voice memory and synthe-
sized by the voice synthesizer section 28 thereby to
produce a voice signal, thus sounding the speaker 29.
.
~ ~ An example of the operation of the system in
5 - .
.
~ .
-
3~
1 response to the depression o~ the ~l~P/RESET key 21 will
be described with reference to this block diagram. When
a STOP/RESET command is applied to the controller 24 by
way of the keyboard 4, the controller 24 first checks
the present operation mode of the system. If the
heating mode i.5 involved, such a control signal as to
stop power supply to the heating source 30 is produced
in order to execute the stop function. In other words,
a TC signal to turn off the time control section 31 is
produced. At the same time, the address selector sec-
tion 26 is impressed with a voice select signal indi-
cating a memory area storing the voice data of "STOP".
In response to this signal, the address selector section
26 produces a predetermined address signal and sequen-
tially updates the same. As a result, the voice data'!STOP" iS produced sequentially from the memory and
applied to the voice synthesizer section 28 such as a
synthesizer so that a voice signal is synthesized to
:~
sound~the speaker 29. Thus, the synthesized human voice
"STOP" is heard upon suspension of heating.
If the controller 2~decides that the program
mode ~is involved, on the other hand, the controller 24
erases~the program data~preset in the controller in
order to exeucte the clear ~unction. At the same time,
25~ the address selector section 26 is supplied with a voice
select signal to select the voice data of "RESET". Thus
~he prcgram data are caneelled while at the same time
l the voice XE~ET~ is heard.
This mode decision is made by the controller
24 checking the RAM of the memory 25. Generally, during
the period when a voice is being synthesized, namely,
during the period when a busy signal is applied to the
controller 24 from the voice synthesizer section 23, the
next entry of a key command is prohibited. If a new key
command is entered during the reporting of an accepted
key function, the intention to ~orm a panel simple to
operate is not realized, so that the function to report
the system mode to the user is lost, thus making it dif-
ficult to understand the next process of operation. The
STOP/RESET function is the only exception which is given
the top priority in acceptance even during the voice
synthesization. This is because of -the emergency nature
of the stop function which is probably used when it is
desired to stop the heating process in such a case as a
; fire started in the heating chamber. The user may
desire to suspend or end the heating halfway in a case
of less emergency such as when the user, checking each
stage by~way of the program recall key 22, comes to know
~a program error. In such a case, it is necessary to
stop the heating as soon as possible. Even if the
synthes1zed voice is still reporting the first stage,
: ~ :
therefore, the STOP/RESET key 21 is accepted and pro-
cessed appropriately. The recall voice reporting is
cancelled.
17 _
.
::,
l The heat source 30 is a magnetron for the
microwave oven and a heater for the electric range. The
heat source 30 is controlled by the tlme control section
31 and the output switch means 32 thereby to execute a
prede~ermined output and a heating time. These opera-
tions are actually realized by the time relay 33 and the
output switch relay 34 and controlled by a time control
signal TC and a power control signal PC. The relays may
be replaced by semiconductor switches such as of a
triac, and the output switching may be performed by
interrupting the power supply or phase control. Numeral
35 shows an auxiliary load such as an even lamp. The
controller 24 produces the TC and PC signals, so that
display data are applied to the display means 36 thereby
to accomplish a predetermined display. the display
means 36 may comprise a 6-grid phosphorescent display
tube 37 operated by 8-bit data signals Do to D7 and scan
signals SO to S5 for sweeping and dynamically lighting
the grids.
20 : ~ ~ In order to ma~e up the thlrd feature of the
pr~esent invention, the controller 24 is further
,
impressed with a clock pulse from the clock signal
;generator sectlon 38 and a detection signal of a gas
inf~rared ray, a~temperature and humidity of the object
~rom the sensor 39~aa a means of judging the~progress of
heating. ~The clock pulse forms a reference data for
controlling the time control means 31 thereby to count
18 -
:
~ .
.
,
- - ~ ~ , ,,
~. ;
~ 3~
1 the lapse of the heating time~ The form of the sensor
39 already in practical use includes a temperature probe
(contact type) with a thermistor encased in the forward
end of a metal bar tube, a humidity sensor for detecting
S the humidity from the object, an infrared ray sensor
responsive to the infrared ray or a gas sensor ~or
detecting a gas. The sensors other than the temperature
probe is of contactless type. A~l the above-men~icned
sensors detect the physical and chemical changes of the
object, and the resulting data are used to estimate the
progress of heating. In the embodiment under con-
sideration, a reference signal is produced from the
controller 24 and compared with the signal from -the sen-
sor 39 at a comparator section 40 for such a detection~
On the basis of the data supplied from the
clock generator section 38 and the sensor 39, the
controller 24 reports the detected heating condition.
The reporting takes the form of a detected temperature,
;~ the lapse of heating time, residual heating time, a time
point when a predetermined quantity of gas or humidity
is detected or a stage switch1ng time point. This
reporting permits the user to know whether the heating
: ~ :
; ~ ~ is going smoothly or not without attending the heating
apparatus. Even lf a heating program error is committed
and ~his is oYerlooked without using a program recall
:
functin or after using the same function, the user has
an increased chance to know a setting error by the
,
- 19 -
'
, '
~ 3~3~
l message automatically announced at intervals. This
makes the most of the advantage of a voice directly and
immediately reaching a distant person. Another feature
of this heating condition announcement is that even if a
malfunction of the system is caused by a noise and a set
heating program is destroyed, "90C" or ''100C'I or like
announcement instead of a preset "80C" will inform the
user of the abnormality. If the residual heating time
is not announced after a considerable time, the system
not functioning normally is inferred.
These heating condition announcements are of
course useful even during normal operation of the
system. For successful heating of the food, it is
necessary to peep into the heating chamber occasionally
lS to make sure that the food is not overheated. The
heating progress announcements according to the present
invention may be uesd as a measure of this heating-
chamber checking. Then as compared with the conven-
~tional heating apparatuses which announce by buzzer only
the~end of the heating, the apparatus is much easier to
use and is capable of cooking the ood more
successfully .
A specific circuit confiquration will be
described below. In Fig. 7, the controller 24 and the
memory 25 are reallzed by a microcomputer 41 with a
memory incorporated in one chip. This microcomputer 41
lS supplied with a key imput signal froma key matrix 42
- 20 -
....
,.
. . .' ,
, ',
3~
1 corresponding to the input signal 23 through a key
strobe signal. The digit scan signals S0 to S4 for
lighting the display tube 37 dynamically are used as the
key strobe signals and applied to the terminals Io to
I3 as a 4-bit key input signal.
The voice synthesizer section specifically
comprises a synthesizer LSI 43 utilizing the voice
synthesizinq techniques such as PARCOR synthesizing pro-
cess and voice memory for giving a parameter to the
synthesizer 43. For simplification of the sy~tem, the
segment signals Seg3 to SegO for display data are used
as address data without any exclusive output port~ Thus
a timing of the address data set is provided by time
sharing of one scan, and after completion of the
display, the address data are produced at Seg3 to
Seg0 and applied to the input ports CTLl to CTL8 of the
synthesizer 43 by the PDC signal. Fig. 8 shows the
timing for this operation in which the address data are
present in five parts. (LOAD ADDRESS)
~0 The de~oded address data are applied to the
terminals ADDl to ADD8 and loaded in the voice memory 27
by the Il signal.
:
A~ter the address ~s loaded, the data begins
~to be read out by the Io signal. The data appears bit
by bit at the ADD8 port and is read into the synthesizer
These data are a parameter for operating the synthesizer
; ~ and extracted by analysis of the voice~
- 21
,
: ,- '
'
: : ~: ' - ,
-
~ 3 ~ ~ ~
1 This parameter is processed in the synthesizer
43 and produced at SPKl and SPK2 as a voice electrical
signal. This is an output of a D/A converter, which is
waveform shaped and amplified and then restored as a
voice from the speaker 29.
In time counting or heating time control(timer control) J the clock pulses are stopped so that
further time counting or timer control is impossible if
the clock line forming the basis of time counting failsO
In ~imer control, such a failure causes the heating to
continue endlessly, thus leading to a fire of the object
to be cooked. This is called a clock pulse error
Sensor wire breakage or short circuiting is
also a cause of heating failure. Especially, the wire
breakage, like the above-mentioned timer stoppage, is a
serious fault giving a danger of a fire attributed to
continued heating~ This is ~called a sensor wire
; breakage error.
First, the method of detecting a clock pulse
error will be described. The microcomputer 41 comprises
another timer means for counting the number of scans of
the d1splay tube 37 in addition to the timer means for
counting the clock pulses supplied from the clock pulse
generator section 38. Such an additional timer means
f;unctlons~ as long as ~the oscillator 43 of the microcom-
; puter 41 operates. This timer is placed in the RAM and
~ is capable of counting for three seconds or other lenqth
: ~ :
~ 22 -
: .
~, . : , ~ - :
,' ~ ,: . ~ , , : .
.
, ~
2~
l of time based on the time required for one scan, say,
about 10 msec. If a clock pulse is supplied during this
timer this soft logic timer is cleared and therefore
does not function. If a clock signal fails to be
supplied, however, the soft logic timer continues to
operate without being cleared, and after counting of
three seconds, a carry occurs. This carry immediately
stops the heatinq through the microcomputer, so that an
alarm and a timer stop are announced orally. This
informs the user that the heating has failed and the
timer is out of order and cannot operate, thus allowing
him to call a serviceman or take another appropriate
measure. In this way, the foolish and dangerous act of
proceeding with the heating with the timer broken is
prevented.
Similar measures are taken in case of a fault
of the sensor. The breakage of sensor wire i5 detected
by the steps mentioned below. Reference voltages
REYo to REF4 are capable of producing 32 voltage levels.
Numeral 44 shows a switching element such as a C-MOS
inverter which, in ~ooperation with the ladder 45, con-
verts a digital siqnal of 32 levels into an analog
slgnal and applies it to the comparator 40. The ends of
this reference voltage namely, X 00 and X IF are used as
~; 25 detection levels of shorting and opening, and a prac-
tical level is designed inwardly of this range, such as
between X 03 and X IC, thus enabling the shorted or open
~: ~
~ - 23 ~
'''' ~:
' : ' ` ' ' ~ ' '
'
:,
~.~tj9~
l conditions of the sensor to be detected.
A sectional view of the heating chamber is
shown in Fig. 9. The object to be heated 47 is disposed
in the heating chamber 46, and radiated with microwave
by the magnetron 48. On the other hand, the sensor 39
is disposed within the air guide 49. The magnetron 48
is cooled by the cooling fan 50, and the heating chamber
46 is ventilated. The electrical resistance value
greatly changes in response to the gas, temperature and
relative humidity of the inner air flow. Numeral 51
shows a door, and numeral 52 shows a mount rotating
motor for eliminating the heating variations of the
object 47 by rotating the mount 53.
The control program of the microcomputer will
be briefly explained. This program is stored in the ROM
of the microcomputer and is engaged in various system
operations described above~ A flowchart of the system
operations is shown in Fig. 10, in which the startin~
;point is ENTRY. first, all the output ports of the
micrcomputer are re~et and the ~AM is cleared. A prede-
t~rmined constant is loaded in a predetermined address
of the ~AM. This is the initialization process of the
mlcrocomputer.
Then the figure S is preset in the ladder
digit register in the RAM and the figure 7 in the scan
digit register~ These are decremented by the next scan
digit modification and ladder digit modification and
:: ~
- 24 _
:
'
; ' ~
:
. ~:
9g~
1 ~orm ~as1c data ~or time sharlng o~ the system.
The timing controlled by the scan digit is 7
periods from 6 to 0. At the period 6, no work for
display is performed but a reference level for reading
the sensor data is produced. The reference level inclu-
des Ref4 to RefO, which are asigned with the five
periods from 4 to O by the value of the ladder digit
modification register. A bit is set in descending order
from the significant bit Ref4 o~ the reference level
every one scan, and decision is made on the output (SNS)
of the comparator 40 under the respective state. By
repeating the set and reset every bit in this way, all
the sensor data are prepared. At the 6th scan, the
ladder modification is completed and the sensor data are
judged thereby to estimate the heating progress. If the
heating progress is required to be announced at this
time, predetermined voice address data are set in the
RAM and produced sequentially from the next scan~
At the periods 5 to 0, the display tube 3? i5
;20~ 11t dynamically.~ In other words, display data are pro- -
duced at~Seg7 to SegO, followed by the llghting of a
; prèdetermined~d~igit.~ At the same time, the key~matrix
42~is scanned~at~SC4 to SCO, and the key data are
collected.
25~ Upon completion of these displays and key pro-
cessing, the relays~33 and 34 for the output control
section~32~and the heating time control section 31 and
25 ~
:
.
, :
~ ~6C~
tne next up/~own of the timer means are set or reset.
And the transfer i~ made back to the start o~ the scan
routine again.
: ~ :
:: :: :
~ :~
: ~ ` :
- 26 -
.
.:
