SIMATIC S7-1500 PLC Hardware Interrupt Organization Block and Its Application Introduction

Hardware interrupt organization block and its application

Hardware interrupt organization blocks (such as OB40) are used to quickly respond to signal changes of signal modules (SM), communication processors (CP) and function modules (FM).

After the hardware interrupt is triggered by the module, the operating system will automatically identify which slot of the module and which channel in the module generated the hardware interrupt. After the hardware interrupt OB is executed, a channel confirmation signal will be sent.

If an interrupt event is being processed and the same interrupt event occurs in the same module and the same channel, the new interrupt event will be lost.

If an interrupt event occurs in other channels or other modules in the same module while an interrupt signal is being processed, the temporarily stored interrupt will be processed after the currently activated hardware interrupt is executed.

The following example illustrates how to use the hardware interrupt organization block.

[Example] Write a command to record the number of times the user uses the 10.0 button, making it a simple "black box".

[Solution] ① Add organization block OB40. In the project tree of the TIA Portal project view, double-click "Add new block" to pop up the interface shown in Figure 1. Select the "Organization block" and "Hardware interrupt" options, and click the "OK" button to add the OB40 organization block.

Figure 1

② Select the hardware module "DI16×24VDC HF", click the "Properties" tab, as shown in Figure 2, select "Channel 0", enable rising edge detection, and select the hardware interrupt organization block as "Hardware interrupt".

Figure 2

③ Write a program. Write a program in the organization block OB40 as shown in Figure 3. Each time the button is pressed, the program in OB40 is called once, and the value in MW10 is increased by 1, which records the number of times the button is used.

Figure 3