Central Heating Control System V10 (CHCSV10) - Entity Relationship Diagram, Data Flow Diagram, Control Flow Diagram, Process Specification, Control Specification

This article provides detailed information about Central Heating Control System V10 (CHCSV10) including Entity Relationship Diagram, Data Flow Diagram, Control Flow Diagram, Process Specification, Control Specification. It also includes a Process Activation table. The article is relevant for students studying courses related to control systems, heating systems, and database management.

Central Heating Control System V10 (CHCSV10) 1
Central Heating
Control System V10
(CHCSV10)
Student id: -
Student name: -
Date: -

Central Heating Control System V10 (CHCSV10) 2
Table of contents
1. Entity relationship diagram (ERD) ………………………………………………………………………………………….3
2. Data Flow diagram (DFD) ………………………………………………………………………………………………………6
3. Control Flow Diagram (CFD) …………………………………………………………………………………………………..8
4. Process Specification (PSPEC)……………………………………………………………………………………………….10
5. Control Specification (CSPEC) ……………………………………………………………………………………………...15
5.1 Process Activation table ………………………………………………………………………………………….…..15
5.2 State Machine Diagram (SMD) ……………………………………………………………………………………..15
6. Data dictionary ……………………………………………………………………………………………………………………16
7. Bibliography ………………………………………………………………………………………………………………………….17

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1. Entity relationship diagram (ERD): -
I create this entity-relationship diagram according to given requirements. According to the
required system Display unit system all the information related to Control heating system. Users
communicate with the system by using System display unit. By using this system display user set
temperature, timer, and status of all components of the system. But Control Heating unit
communicate with system display by using the system control panel. If Control heating system is
operational then system control panel display the output on the system display unit. So we can
say that there is many to many relationships between Control heating system and system display.
I create nine entities according to the requirements. And there are the following: -
 Entities: -
1. System Display: - system display entity store all information that displays on the
system display at that time. For example heating unit state, temperature, number
of Ducts open, close, Gas meter reading etc.

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2. System Control Panel: - system control panel store information system display
and control heating system. It means that this entity store foreign key of system
display entity and Control Heating System.
3. Control Heating System:- Control Unit entity store all information of heating
unit, system temperature controller, Ducts, gas meter, heating unit fan and the
system clock. It means that this entity store all foreign keys of heating unit entity,
Ducts entity, Gas Meter entity, Heating Unit Fan entity and System Clock entity.
4. Heating Unit: - Heating Unit entity store information different heating unit
number, heating capacity, state, operating/not- operating etc.
5. System Temperature Controller: - System Temperature Controller entity store
information related to Heating Unit Temperature. Because it is a process of the
heating unit.
6. Ducts: - Ducts entity store information related to each Duct, state of duct etc.
7. Gas meter: - Gas meter entity store information related to the state of the gas
meter, gas meter reading, operating/ not- operating etc.
8. Heating Unit Fan: - Heating Unit Fan entity store information related to each
heating fan, state of the heating fan, operating/ not- operating etc.
9. System Clock: - System Clock entity store information related to date, time, the
day of the week, the vital component in the real-time actions of the system.
 The relationship between entities: -
1. 1: 1 relationship between Heating Unit and System Temperature Control entities. A
Heating Unit System has one and only one System Temperature Control and each
System Temperature Control has one and only one Heating Unit System.

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2. 1: M relationship between System Display and System Control Panel entities. a
System Display has one or many System Control Panel but each System Control
Panel has one and only one System Display.
3. 1: M relationship between Central Heating System and System Control Unit entity. A
Central Heating System has one or many System Control Unit but each System
Control unit has one and only one Central Heating System.
4. 1: M relationship between Central Heating System and Heating unit entity. A Central
Heating System has one or many Heating Unit but each Heating Unit has one and
only one Central Heating System.
5. 1: M relationship between Central Heating System and System Clock entity. A
Central Heating System has one or many system Clock but each System Clock has
one and only one Central Heating System.
6. 1: M relationship between Central Heating System and Heating Unit Fan entity. A
Central Heating System has one or many Heating Unit Fan but each Heating Unit Fan
has one and only one Central Heating System.
7. 1: M relationship between Central Heating System and Gas Meter entity. A Central
Heating System has one or many Gas Meter but each Gas Meter has one and only one
Central Heating System.
8. 1: M relationship between Central Heating System and Ducts entity. A Central
Heating System has one or many Ducts but each Duct has one and only one Central
Heating System.

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2. Data flow diagram (DFD): -
This data flow diagram creates according to system requirements. In this diagram Heating
System Database store all the database of the Central heating system. Here only one external
entity that is the user. The only the user can communicate with this system. In this diagram, I
create four processes and there are the following: -
1. Setting System Clock: - in this process firstly user send the request to the Central
heating system to set the system clock. Then Central heating system accepts the request
and set the system clock according to user requirement and display the result on the
system display. The user can set day of the week, date, time timer etc. in this process.
2. Setting Heating Program: - in this process user sends a request to the central heating
system to set the heating program. The system accepts the user request and set heat
according to user requirement and display result on the system display.
3. Temperature Configuration: - in this process, the user sends a request to the central
heating system to set and configure the temperature. The central heating system accepts
the request and set temperature according to user requirement and display output on the
system display.
4. Power Down/ up: - in this process, user sends the request to the central heating system to
Power down/ up the system. The system checks the status and set the command
according to user requirement and gives the result.
5. Change State of gas meter, Ducts, Heating Fan unit: - in this process user request
change state of gas meter/ Ducts/ Heating Fan unit to the central heating system. The
system checks the state and set state according to user requirements and display result on
system display unit.

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3. Control flow diagram (CFD): -
I create control flow diagram according to case system. This diagram shows the flow to control
of the whole system. Firstly the user gives input to the Central heating system by using the
system display unit. We know that user only communicates with the system display and system
display communicate with the central heating system by system control panel. So that when user
set inputs on system display then that input accept by system display and to system control unit
then that unit sends inputs to the central unit system.
Now the central heating system firstly set the system clock and checks the temperature
specification. If the user input matches with current status to the system then system work as
same and produces ware air. But if user inputs are different as compare to system state then the
system checks gas availability. If gas is not available then stop system and control goes to start
the process. If gas is available then configure the gas flow and check heating unit availability. If
the heating unit not available then stop system working and send control to start the process. If
heating unit available then on the circulation of the heating unit and check heating fan is
available or not. If the heating fan is not available then stop system and control goes to start the
process. But if the heating fan is available then on heat pass by ducts and checks ducts are
>=50% open or not. If ducts are not >=50% open then system stop working and control goes to
starting the process. But if ducts are >=50% open then heating fan produce warm air by using
ducts.

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4. Process Specification (PSPEC): -
PseudoCode:
SetTime:
1. set curr = Current_Clock_Time
2. GET new_time
3. if button is OK, SET Current_Clock_Time= new_time
4, if button is Cancel, SET Current_Clock_Time=curr
5. END
Configure_System_Clock
1. START
2. if button is '24 Hour', SET Current_Time_FORMAT= '24 Hour '
3. if button is '12 Hour', SET Current_Time_FORMAT= '12 Hour'
4.END
Configure_Temprature_Detector
1. START
2. if button is 'Farenhite', SET Current_Temprature_FORMAT= ' Farenhite '
3. if button is 'Celsius', SET Current_Time_FORMAT= 'Celsius'
4.END
Set_Heating_Program
1. START

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2. set sTime=START_TIME
3. set eTime=END_TIME
4. set sTemp=START_TEMP_RANGE
5. set eTemp=END_TEMP_RANGE
6. GET START_TIME
7. GET END_TIME
8. GET START_TEMP_RANGE
9. GET END_TEMP_RANGE
10. if button is OK, SAVE
11. if button is Cancel, SET START_TIME=sTime, END_TIME=eTime,
12.START_TEMP_RANGE=sTemp, END_TEMP_RANGE= eTemp
13. END
Turn System Off
1. Close Ducts
2. Stop Gas Supply to Heating Units
3. Stop heat fan
4. Stop Heating Unit
5. Set Heat_Unit='UnAvialable'
6. Set Heat_Fan='UnAvaialble'
7. Display 'Central Heating System is Off'
8. END
Turn System On
1. if not in manual mode, open ducts

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2. if open_ducts/totalducts<0.5, Display 'Please open ducts. Heating Unit is OFF' and GO
TO END
3. start gas supply
4. Set Heat_Unit='Avialable'
5. Set Heat_Fan='Avaialble'
HeatingDuct Controller
1. if scheduledtime, go to step 2, else go to step 5
2. for each duct go to step 3
3. If duct is OPEN, send 'OPEN' with 'DUCT ID' to display
4. If duct is NOT OPEN, send 'CLOSE' with 'DUCT ID' to display
5. END
Gas Meter Supply Controller
1. if scheduledtime, go to step 2, else go to step 5
2. set staus= gas connection availability
3. if status='AVAILABLE', send GAS AVAILABLE to display
4. if status='UNAVAILABLE', send GAS NOT AVAILABLE to display
5. END
Heating Unit Controller
1. if scheduledtime, go to step 2, else go to step 5
2. set staus= Heating Unit availability
3. if status='AVAILABLE', send Heating Unit AVAILABLE to display

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4. if status='UNAVAILABLE', send Heating Unit NOT AVAILABLE to display
5. END
Heating Unit Fan Controller
1. if scheduledtime, go to step 2, else go to step 5
2. set staus= Heating Unit Fab availability
3. if status='AVAILABLE', send Heating Unit FANAVAILABLE to display
4. if status='UNAVAILABLE', send Heating Unit FAN NOT AVAILABLE to display
5. END
System Temperature Detector
1. if scheduledtime, go to step 2, else go to step 4
2. set temp= current temprature
3. send temp to display
4. END
SystemControlPanel
1. Receive temprature from System Temperature Detector
2. Get time from System clock
3. If AutomaticHeating is ON and time in HeatingTime
4. if temprature >= requiredTemprature, continue
5. if temprature < requiredTemprature, status=checkGasConnection
6. if status is not 'Available', Display 'Can't heat as gas is not available'

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7. if status is 'Available', status= checkHeatingUnitStatus
8. if status is not 'Available', Display 'Can't heat as Heating Unit is not available'
9. if status is 'Available', status= checkHeatingUnitFanStatus
10. if status is not 'Available', Display 'Can't heat as Heating Unit Fan is not available'
11. if status is 'Available', status= checkDuctsStatus
10. if status is not 'Available', Display 'Can't heat as 50% ducts are not open
12. if status is 'Available', TURN SYSTEM ON
13. Display'Heating in Progress'
14. Exit

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5. Control Specification (CSPEC): -
5.1 Process activation table: -
Process Activation table
S.NO. Occurrence of event Activated process
1 System Turn On Gas Unit Controller
2 Gas Unit Turned On Heating Unit Controller
3 Heating Unit Turned On Heating Fan Unit Controller
4 Heating fan Unit Turned On Ducts Unit Controller
5 Ducts Open Start Heating
6 System Turned Off Turn Gas, Heating Unit and Heating
Fan Unit Off
7 Temperature Below Required Turn System On
5.2 State machine diagram: -
State Machine Diagram describes the flow of the System when the System is Turned On and vice
versa.
When the System is turned on, the control goes to Gas Unit Controller which checks whether the
gas is available or not. If available, the control passes on to Heating Unit where the Heating unit
controller checks the availability of this Unit. If this Unit is available then its fans are checked
and the control passes on to check that whether half of the ducts are open or not. If half of the
ducts are open, then the System is turned on and the heating of the System starts. When the
control flows back, all the Systems are turned off. In the attached State Machine Diagram, we are
showing this State of the System which is changing as the control flows from one unit to other. If
any of the Unit fails, eg. Gas unit is not working, the system is turned on and an error message is
displayed on the display panel. So, the System goes again back to the initial state from where it
started.

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6. Data Dictionary: -
We have used some special terms
1. System Controller: It controls and operates the basic functionality of the System. It also
coordinates with the other units like temperature recording Unit, System clock etc.
2. Heat Unit Controller: It controls the Heat Unit that whether it is working fine or not. It is
also responsible for turning it ON and OFF. It also checks the status of the Heating Unit
after regular intervals and sends the status to System Controller.
3. Heat Unit Fan Controller: It is responsible for controlling the fan of Heat unit. It controls
the fan, checks its functionality and is responsible for turning it on and off. It also checks
the status of the Heating Fan Unit after regular intervals and sends the status to System
Controller.
4. Gas Unit Controller: It is responsible for checking the connectivity of gas and turning it
ON and OFF. It also checks the status of the Gas Unit after regular intervals that whether
the gas is available or not and send the status to System Controller.
5. System Temperature Recorder: It is responsible for recording and sending the current
temperature of the location to the System controller after regular intervals.

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6. Duct Controller: It is responsible for the opening and closing of ducts. It also checks the
current status of various ducts and sending its status to the System Controller.
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