Sample31: Functionblock TON in TwinCAT3 C++
This article describes the implementation of a behavior in C++, which is comparable with a TON function block of PLC / IEC-61131-3.
Source
Here you can access the source code for this sample.
- 1. Unpack the downloaded ZIP file.
- 2. Using a Visual Studio with TwinCAT installed, open the project via Open Project ....
- 3. Configure signing for this project by switching on TwinCAT signing with a right-click on Project->Properties->Tc Sign and configure your certificate and password if necessary.
For more information on signing C++ projects, click here. - 4. Select your target system.
- 5. Build the sample (e.g. Build->Build Solution).
- 6. Activate the configuration by clicking on
.
- The sample is ready for operation.
Description
The behavior of this module is comparable with a module that was created with the Cyclic IO wizard. m_input.Value is added to m_Output.Value. As opposed to the Cyclic IO module, this module only adds m_input.Value to m_Output.Value if the defined time interval (1000 ms) has elapsed.
This is achieved with the help of a CTON class, which is comparable with the TON function block of PLC / 61131.
Understanding the sample
The C++ class CTON (TON.h/.cpp) provides the behavior of a TON function block of PLC / 61131. The Update() method is comparable with the rump of the function block, which has to be called regularly.
The Update() method contains two "in" parameters:
- IN1: Starts the timer switch on a rising edge and resets the timer switch on a falling edge.
- PT: Describes the time to wait before Q is set.
And two "out" parameters:
- Q: TRUE if PT exhibited a rising edge seconds after IN.
- ET: Designates the elapsed time.
Beyond that, ITcTask must be provided to query the time base.