How to Use PLC Timer Functions to Turn an LED On/Off
This tutorial shows you how to use Timer Functions to turn an LED Light on and off using an HMI+PLC combo and displaying on the user-interface.
Software Required
Hardware Required
HMC4070A-M – Other HMC2000/HMC4000 models can also be used
Refer to the Digital Output Tutorial Pages to see the wiring diagrams for turning the digital output on and off for an LED light.
HMI + PLC Combo
TON (On Timer)
Software Code (Ladder Diagram)
Operands
Logic Block Expression
The timer starts on a rising pulse of IN input. It stops when the elapsed time is equal to the programmed time. A falling pulse of IN input resets the timer to 0. The output signal is set to TRUE when programmed time is elapsed, and reset to FALSE when the input command falls. Timer register depends on base. Base will be changed to 1ms.
Logic Block Example
OFF
ON After 5 Seconds
Software Code (Structured Text)
Another type of IEC Language you can use:
OnTimer ( Button1, T#5000ms ) ;
LED1 := OnTimer.Q ;
User-Interface Screenshot
When the toggle bit is pressed, it will turn the LED on AFTER 5 seconds.
It will turn it off immediately with another press of the toggle button.
TOF (Off Timer)
Software Code (Ladder Diagram)
Operands
Time Diagram
Logic Block Expression
The timer starts on a falling pulse of IN input. It stops when the elapsed time is equal to the programmed time. A rising pulse of IN input resets the timer to 0. The output signal is set to TRUE on when the IN input rises to TRUE, reset to FALSE when programmed time is elapsed.
Logic Block Example
ON
OFF After 5 Seconds
Software Code (Structured Text)
Another type of IEC Language you can use:
OffTimer ( Button2, T#5000ms ) ;
LED2 := OffTimer.Q;
User-Interface Screenshot
When the toggle bit is pressed, it will turn the LED on immediately.
When the toggle bit is pressed again, it will turn the LED off AFTER 5 seconds.
TON (On Timer) + TOF (Off Timer)
Software Code
Refer to the TON (On Timer) and (TOF Off Timer) Sections for the Operands and Time Diagrams
Logic Block Expression
OFF After 5 Seconds
Logic Block Example
ON After 5 Seconds
OFF After 5 Seconds
Software Code (Structured Text)
Another type of IEC Language you can use:
OffTimer2 ( OnTimer 2.Q, T#5000ms ) ;
LED3 := OffTimer2.Q;
OnTimer2 ( Button3, T#5000ms ) ;
User-Interface Screenshot
When the toggle bit is pressed, it will turn the LED on AFTER 5 seconds.
When the toggle bit is pressed again, it will turn the LED off AFTER 5 seconds.
TOFR (Off Timer with Reset)
Software Code
Refer to the TON (On Timer) and (TOF Off Timer) Sections for the Operands and Time Diagrams
Logic Block Expression
Logic Block Example
ON
OFF After 5 Seconds
Software Code (Structured Text)
Another type of IEC Language you can use:
OffTimerwithReset ( Button4, T#5000ms, Reset ) ;
ResetTimer := OffTimerwithReset. ET;
LED4 := OffTimerwithReset.Q;
User-Interface Screenshot
When the toggle bit is pressed, it will turn the LED on immediately.
When the toggle bit is pressed again, it will turn the LED off AFTER 5 seconds.
When the Reset momentary bit is pressed, the timer turns off. The state is whatever was last pressed.
Sample Project
The project shown above was designed for the specific hardware mentioned at the beginning of the tutorial and is intended to provide you guidance when programming your unit. If you are using models other than the ones specified in this sample project, similar steps can be duplicated within your own project.
Download MAPware sample project
Resources & Documentation
HMC/MAPware-7000 Resources
- MAPware-7000 Getting Started Guide
- MAPware-7000 Programming Manual
- IEC 61131-3 Programming Guide for MAPware-7000
- HMC3 I/O Module Guide
More
See our Support Center for a complete list of Quick Start and Installation Guides