Automatic Highway Lights Program using RTC in Omron PLC

Learn the RTC function (Real Time Clock) on the Automatic Highway Lights program using the Omron PLC CX-Programmer software for beginners.

Contents

Automatic Highway Lights

This PLC program has 5 buttons and 1 Selector Switch, The START_SYSTEM (0.00) button is used to turn ON the system, the STOP_SYSTEM (0.01) button is used to turn OFF the system, and the LAMP1_BUTTON (0.03) button is used to turn ON Lamp 1, the LAMP2_BUTTON (0.04) button is used to turn ON Lamp 2, the LAMP3_BUTTON (0.05) button is used to turn ON Lamp 3.

Selector Switch SELECTOR_MODE (0.02) is used to select Manual or Auto system mode.

By default, the PLC system will Run in Manual mode. The system will be in a standby state when the START_SYSTEM (0.00) button is Pressed, and the system will be OFF when the STOP_SYSTEM (0.01) button is Pressed.

Manual Mode

When the system is Running in Manual mode all outputs can only be turned ON using the buttons. Output LAMP1 (100.00) will be ON if the LAMP1_BUTTON (0.03) button is Pressed, Output LAMP2 (100.02) will be ON if the LAMP2_BUTTON (0.04) button is Pressed, and Output LAMP3 (100.03) will be ON if the LAMP3_BUTTON (0.05) button is Pressed.

Auto Mode

In general, highway lights will turn On in the evening (17.00) and will automatically turn OFF in the morning (06.00). So the time parameters need to be set in the memory words SV_HOUR_ON (D0-D1) “D0 = 0000 & D1 = 0017” and SV_HOUR_OFF (D10-D11) “D10 = 0000 & D11 = 0006”.

Automatic Highway Lights Program using RTC in Omron PLC

Inputs and Outputs

Comment	Input (I)	Output (Q)	Word Memory	Memory Bits
START_SYSTEM	0.00
STOP_SYSTEM	0.01
SELECTOR_MODE	0.02
LAMP1_BUTTON	0.03
LAMP2_BUTTON	0.04
LAMP3_BUTTON	0.05
LAMP1		100.00
LAMP2		100.01
LAMP3		100.02
SV_HOUR_ON			D0-D1
SV_HOUR_OFF			D10-11
SYSTEM_ON				W0.00
MANUAL_MODE				W0.01
AUTO_MODE				W0.02
IR_LAMP1				W0.10
IR_LAMP2				W0.11
IR_LAMP3				W0.12
IR_AUTO				W0.13

Program in Omron PLC

RUNG 0 (SYSTEM ON)

In this Rung, when the START_SYSTEM (0.00) button is pressed, the memory bit SYSTEM_ON (W0.00) changes to the HIGH state. The memory bit SYSTEM_ON (W0.00) will remain in the HIGH state even though the START_SYSTEM (0.00) button has been Released because it uses Latching.

If the STOP_SYSTEM (0.01) button is Pressed, the memory bit SYSTEM_ON (W0.00) will change to a LOW state.

Omron PLC real-time clock street lighting program

RUNG 1 (AUTO & MANUAL MODE)

In this Rung, when the NO contact of memory bit SYSTEM_ON (W0.00) in the HIGH state and the Selector Switch SELECTOR_MODE (0.02) in the LOW state, the memory bit MANUAL_MODE (W0.01) will change to the HIGH state.

When the Selector Switch SELECTOR_MODE (0.02) is changed to HIGH state, the memory bit AUTO_MODE (W0.02) will become HIGH and the memory bit MANUAL_MODE (W0.01) will become LOW state.

RUNG 2 (LAMP 1 MANUAL BUTTON)

In this Rung, when the NO contact of memory bit SYSTEM_ON (W0.00) in the HIGH state and the LAMP1_BUTTON (0.03) button is pressed, the memory bit IR_LAMP1 (W0.10) will become a HIGH state.

RUNG 3 (LAMP 2 MANUAL BUTTON)

In this Rung, when the NO contact of memory bit SYSTEM_ON (W0.00) is in the HIGH state and the LAMP2_BUTTON (0.04) button is pressed, the memory bit IR_LAMP2 (W0.11) will become a HIGH state.

RUNG 4 (LAMP 3 MANUAL BUTTON)

In this Rung, when the NO contact of memory bit SYSTEM_ON (W0.00) is in the HIGH state and LAMP3_BUTTON (0.05) button is pressed, the memory bit IR_LAMP3 (W0.12) will become a HIGH state.

RUNG 5 (RTC AUTO)

In this Rung, when the NO contact of memory bit AUTO_MODE (W0.02) in the HIGH state and the RTC time is above “17.00”, then the memory bit IR_AUTO (W0.13) will change to the HIGH state.

The memory bit IR_AUTO (W0.13) will change to LOW state when the RTC time is above “06.00”.

RUNG 6 (OUT LAMP1)

The LAMP1 (100.00) output will be ON if the NO contact of memory bit IR_LAMP1 (W0.10) or IR_AUTO (W0.13) is in the HIGH state.

RUNG 7 (OUT LAMP2)

The LAMP2 (100.02) output will be ON if the NO contact of memory bit IR_LAMP2 (W0.11) or IR_AUTO (W0.13) is in the HIGH state.