A furnace is heated up to 220 degrees. Once it reaches 220 degrees, the heating stops. Then, the system waits for the temperature to drop to 180 degrees. When the temperature falls to 180 degrees, the furnace starts heating up again to 220 degrees. If the time it takes to rise from 180 degrees to 220 degrees exceeds 10 minutes, a warning lamp turns on.

Can you help me draw the Ladder Diagram for my homework?

 

You just did it yourself, as a Ladder or Logic drawing is ont a pictorial translation of your paragraph!

 

I tried many times but it didn’t work. I make these part but i am not finishing the system.

 

You just did it yourself, as a Ladder or Logic drawing is ont a pictorial translation of your paragraph!

I tried many times but it didn’t work. I make these part but i am not finishing the system.

 

Your first rung is classic seal-in logic with your start/stop. Think about using that same structure for your heating circuit. The last rung will just run the heat as long as temperature is below 220. That's not what you want. Instead, think of your "start heating" conditions and your "stop heating" conditions and use them to build another seal-in rung. You have the conditions very well defined in your paragraph, which is a good start.