The ladder diagram of traffic light program written by Siemens plc300 is shown in the above figure:

The specific operation steps of constructing pulse program with Siemens PLC300 timing block are as follows:

1. First, the main cable should be displayed on the screen.

2. Then drag the main cable window to the left for us to find the timing block.

3. At this time, insert the start button, here is a simple button, and it is best to make a flute self-locking in practice.

4. Then insert the timing block into the main cable and input the pulse time and tag number.

5. Then, two time normally closed points are added to realize interlocking.

6. If you want to debug on hardware, you can add two more output lights for debugging.