![]() ![]() Port pin P0.5 is used to control the pump. All these port pin are high (all sensor probes are open) means the tank is empty. The same applies to other sensor probes (3/4, 1/2, 1/4) and the microprocessor understands the current level by scanning the port pins P2.4 ,P2.5, P2.6 and P2.7. ![]() Now its collector voltage goes high and high at P2.4 means the tank is not full. When water level goes below the full level probe, the base of Q2 becomes open making it OFF. The collector of Q4 is connected to P2.4 and a low voltage at P2.4 means the over head tank is not FULL. Whenever water rises to the full level current flows into the base of transistor Q4 which makes it ON and so its collector voltage goes low. ![]() Consider the topmost (full level) probe, its other end is connected to the base of transistor Q4 through resistor R16. The probes for sensing 1/4, 1/2, 3/4 and FULL levels are placed with equal spacing one by one above the bottom positive probe. A positive voltage supply probe goes to the down bottom of the tank. Have a look at the sensor probe arrangement for the overhead tank in Fig1. The level sensor probes for the overhead tank are interfaced to the port 2 of the microcontroller through transistors.
0 Comments
Leave a Reply. |