Heating element
Heating
element
Controller
Temperature
sensor
220V AC
I/O panel
Requirements – natural language
1.
The user shall be able to use a simple panel to define time
intervals, consisting of
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Starting time
Ending time
Temperature during this interval – Ta
The time intervals are not allowed to overlap
The user shall be able to use a simple panel to define a
temperature tolerance value d.
If the user don't set a temperature tolerance, the system shall use
default value d = 2oC
If the temperature falls below Ti – d, the heather shall be turned
on
If the temperature exceeds Ti + d, the heather shall be turned off
If time is outside all defined intervals the temperature shall be set
to a predefined default value T0.
Requirements – boilerplates
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<user> shall be able to <define> <time interval a = [ts, te]>
<user> shall be able to <set> <temperature Ta for time interval a>
<user> shall be able to <set> <temperature tolerance d>
If <temperature tolerance not set>, <system> shall <set> <temperature tolerance
= 2>
<system> shall have <simple input / output panel>
<system> shall have <heating unit>
<system> shall have <default temperature = T0>
In order to <measure temperature>, <system> shall have <temperature sensor>
In order to <control temperature>, <heating unit> shall have <on / off switch>
If <temperature sensor reading exceeds T + d>, <system> shall <switch off
heating unit>
If <temperature sensor reading is below T - d>, <system> shall <switch on
heating unit>
When <time in [ts, te] for interval a>, <system> shall <set> <T = Ta>
<system> shall <sample> <temperature sensor> at least <3> times per <minute>
<system> shall not allow <time intervals> to <overlap>
If <time is outside all time intervals>, <system> shall <set> <T = T0>