sequence controller

8/3/2019 Sequence Controller

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CREATIVE ELECTRONICS & AUTOMATION

Consultants, Designers and Manufacturers

Sequence Control SystemVersion 1.1

(Two Air-Conditioners Control)

USER MANUAL

© Creative Electronics and Automation#142 Industrial Triangle, Kahutta Road, Islamabad, Pakistan

Phone 92-51-449200-03 • Fax 92-51-2277946, 4492004 WWW.CRESTPAK.COM

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Table of Contents

1. Introduction1.0 Features

1.1 Parameters Setting

1.2 Factory Default Settings

1.3 Parameters Range

2. Work Principle of Sequence Controller2.0 Switching & Power ON Delay

2.1 Auto/Test Mode of Operation

2.2 Temperature based ON/OFF Sequencing

2.3 Time based ON/OFF Sequencing

2.4 Fire Alarm Relay and Buzzer

2.5 High temperature Relay and Buzzer

2.6 Example: Parameters Setting

2.7 Connections Detail

3. Computer Interfacing

4. Software Description4.1 Main Screen Detail

4.2 Communication Port Selection4.3 Operating Mode Selection.

4.4 Parameters Value Setting.4.5 Mini Screen.

4.6 Temperature Vs Time Graph.

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Sequence Control System(Two Air-conditioners Control)

1. Introduction.The Sequence Control System has been designed to control the automatic sequencing

of two Air-conditioners. The ON/OFF sequencing of the Air-conditioners is based on

temperature and time dependent. The data retention memory has been used to save theuser parameters and time passed by each air-condition. The time based ON/OFF

sequencing efficiently utilizes life span of both Air-conditioners.

1.0 Features.

1. Microcontroller based system with Digital Temperature Sensor

2. 16X2 LCD Display With Back Light.3. Data retention Memory for Time and Temperature settings.

4. PC based Interface Software using RS232 Port.

5. Printable and Zoom-able Graph represents room temperature & Set Values for 30Days with sampling rate of 1 min.

6. Min/Max Gauge to Shows Room temperature and Set Values.

7. System Beep on Very High temperature or Fire alarm.

8. Parameters setting from Sequence controller Module.9. Parameters setting from Computer Software.

10. Auto and Test Mode control using Software.11. Three minutes Power Start Delay.

12. 1 minute Switching delay for each Air-conditioner.

13. Configurable Set Value for Time.

14. Configurable Set value for Temperature.15. Configurable Set value for High Temperature.

16. Configurable Set Value for Low temperature.

17. Low and Very High Temperature Alarms.18. Buzzer for Very High Temperature and Fire Alarm.

19. Separate Relay for Very High Temperature and Fire Alarm.20. +12 VDC Supply for external use.

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1.1 Parameters Setting.

The user settings are very important to operate this module properly. There are four

parameters for settings.

1. SV Time

2. SV Temperature

3. SV High Temperature4. SV Low Temperature

The following procedure is used to change these settings.

Fig 1.0 Parameters Setting

The user can also view the time passed for each air-condition by pressing and holding set

key in normal operation of sequence controller.

Temperature 27 º C

Fig 1.1 Time Passed By ACs

AC1=ON AC2=OFF

Press Set Key to

Change Time.

Press Set Key to

Change Temp.

Press Set Key to

Change High Temp.

ENTER/EXIT

SET Set Value

Time : 60 min

Press UP/Down Key to change Time.DOWN UP

SET Set ValueEnter/Exit

Temperature : 27 ºC

Press UP/Down Key to change Temperature.DOWN UP

SET Set Value

High Temp: 27 + 3 ºC

Press UP/Down Key to change High Temperature.DOWN UP

SETPress Set Key to Set Value

Change Low Temp. Low Temp: 27 – 3 ºC

Press UP/Down Key to change Low Temperature.

SETTemperature 27 º C AC1 : 25 min

AC1=ON AC2=OFF AC2 : 0 min

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1.2 Factory Default Se

hen the Sequence Controller is first time turned on the following settings are loaded by

. Time 180 minutes

h Temperature 2

.3 Parameters Range

0 º C0 º C

.0 Switching & Power ON Delay

conditioners the start delay is fixed for 3 minutes,

.1 Auto/Test Mode of Operation

e controller will operate in Auto mode while thesoftwar

.2 Temperature based ON/OFF Sequencing

role to control the ON/OFF sequencing

he set value for high temperature is sum of SV Temperature and SV High temp

oth Air-conditioners will turn off when room temperature goes below or equal to Low

ttings

W

default, these settings can also be changed (see user settings for detail).

12. Temperature 26

3. Hysterics for Hig4. Hysterics for Low Temperature 2

1

emperature 10 to 5Set Value TSet Value Low temp Hysterics 1 to 1

Set Value High temp Hysterics 1 to 10 º C

Set Value Time 1 to 720 minutes

2. Working Principle of Sequence Controller

2

For the protection of the Air-

while the switching delay for the Air-conditioners is 1 minute. When the power is turned

ON the message will be displayed “Start Delay 3 min”, this message will remain for first

2 minutes and for last 1 minute status of the air-conditioners will be displayed.

2

At power ON the sequence is used to select the test mode. In test mode both the Air-conditioners can be

turned ON or OFF regardless of room temperature

2

Room temperature plays very important

of Air-conditioners.

Thysterics, while the set value for low temperature is difference of SV Temperature andSV Low temp hysterics.

B

temperature and LCD of the sequence controller and will display the message “Very LowTemp”.

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When room temperature is above the Low temperature and below the High temperature

When the room temperature is above or equal to High temperature and both the air-

he sequence will be perform correctly when normal screen is opened that shows room

.3 Time based ON/OFF Sequencing plays very important role to utilize both the Air-

.4 Fire Alarm Relay and Buzzer

the Air-conditioners will turn OFF, while fire alarm

.5 High temperature Relay and Buzzer

ll turned ON when the room temperature goes

then only one air-conditioner will remain ON. When the set value of time is achieved the

running air-conditioner will turn OFF and the other air-conditioner that was off will turn

ON after 1 minute for the set value of time.

conditioners will run and the message will be displayed on LCD “AC1=ON AC2=ON”.When the temperature goes normal(below high temp) and time passed for the both air-

conditioners is below the set value of time then one of the air-conditioner that was turned

ON later to decrease the room temperature will go OFF and its running time will be saved

in data retention memory of the system.

T

temperature, make it sure that no setting screen is opened. If no key is pressed for 30 secthen the system will jump to main screen automatically.

2 The time based ON/OFF sequencing

conditioners efficiently. When the room temperature is above the low temperature and

below the high temperature then both air-conditioner will run alternately for the set value

of time.

2

When the fire alarm occurs bothRelay and buzzer will turn ON, the buzzer can be turned OFF by acknowledge (Pressing

Set key) or when fire alarm goes off. When the fire alarm input goes OFF, the fire alarmrelay will go OFF and the Air-conditioners will resume their status.

2

High temperature Relay and buzzer wi

two degree above or equal to high temperature. The buzzer can be turned OFF by

acknowledgement (pressing set key) or it will turn OFF automatically when temperaturewill be decreased by one degree, and the high temperature relay will also turn off when

the temperature will be decreased by one degree.

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2 Consider the fo

Set Value High Temp : 27+2 º CSet Value Low Temp : 27-2 º C

S

R

R

R

R

2

RLY1

220 VAC

NO

UP

RLY2

COM

SET/TIM

0

V D C

RLY4

COM

AckRLY3

Transformer

AC1 Relay

Ent/ExitNO

AC2 Relay

DB9

LCD 2X6

C O N T R O L L E R

COM

NOCOM

NO

Fire Alarm Relay

+ 1 2

V D C

High Temp Relay

Back Light

F i r e

A l a

r m

I n p u t

Down

Fig 1.2 Connection Detail

.6 Example: Parameters Setting.

llow settings.

Set Value Temperature : 27 º C

ystem behavior on various room temperatures will be as follows

oom Temperature= 25 ºC or less AC1=OFF AC2=OFF

oom Temperature= 26 to 28 ºC Only One Air-conditioner will be ON

oom Temperature=29 ºC or greater AC1=ON AC2=ON

oom Temperature=31 ºC or greater AC1=ON, AC2=ON, High Temp Relay=ON

.7 Connections Detail

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3. Computer Interfacing

he communication of the sequence controllerT with the computer is also an importantfeature of the system, for this purpose RS232 port has been used for interfacing.

ontroller connection.

he connections of the sequence controller with the pc are shown above in figure 3.0.

ote: Before connecting the software make it sure that sequence controller is operating

Fig 3.0 PC to C

T

The RS232 is full duplex communication, so sequence controller can send and receive

data simultaneously. Only three wires have been used for the communication of the

Sequence controller with the computer, two of them are for send and receive data whilethe third one is for ground.

N

in normal mode not in setting mode.

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4. Software Description.The software interface has been developed to communicate the sequence controller

ature has been displayed in min/max gauge format that shows the room

module with the PC. Using this software the user can not only view the room temperature

and set values but can also can change these settings.

Main Screen

The temper

temperature and low and high temperature settings. The gauge representation of the

temperature and set values makes the conditions easy to understand. The selected setvalues can be viewed on the SET Value section.

Fig. 4.0 Main Screen

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The status of Air-conditioners remaining for both the Air-

ommunication Port Selection.

n can be done by pressing the button “com port”.

perating Mode Selection.he system is auto. The following window is used to change

, time passed and timeconditioners can be viewed on AC1 and AC2 section.

C

The communication port selectioFollowing window will be display for comm port selection.

O The default running mode of t

operating mode of the controller. Control AC1 and AC2 section of the main screen can beused to turn ON or OFF any air-conditioner in test mode.

Fig 4.1 COM Port Selection Screen

Fig 4.2 Mode Selection Screen

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Parameters Value Setting.

eter for set values can be changed either with sequence controller module or

ini Screen.

hen the main window is minimized the small window shown in fig 4.5 will open on the

The param

with the software, connect button at the bottom of the main screen is used to connect thesoftware with sequence controller module. When the module is connected with the pc the

message will be displayed “Connected successfully.” and the text on the button will be

converted to Disconnect, now the same button can be to disconnect the module from PC.The parameter button is used to change the Set Values. The values are changed and

passed individually by pressing send key on the parameter setting window

M

W

desktop that display room temperature and status of the Air-conditioners.

Fig 4.3 Parameters setting Screen

Fig 4.5 mini screen

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