Therefore, the signal for cancelling the lock should be operated by a normally open type control valve. However, to cancel the lock, the same signal must also cancel the locks on other devices, like the indication signal Figure 1.10 shows how the normally closed type control valve can be .  used to cut off the normally open type control valve and achieve the goal of changing the signal.  DIRECT CONTROL OF DOUBLE ACTING CYLINDER The only difference between a single acting cylinder and a double acting cylinder is that a double acting cylinder uses a 5/2 directional control valve instead of a 3/2 directional control valve (Figure Usually, when a double acting cylinder is not operated, outlet and inlet will be 1.11). ‘B’ ‘P’ connected. In this circuit, whenever the operation button is pushed manually, the double acting cylinder will move back and forth once In order to control the speed in both directions, flow control valves are connected to the inlets on both sides of the cylinder. The direction of the flow control valve is opposite to that of the release of air by the flow control valve of the single acting cylinder. Compared to the throttle inlet, the flow control valve is tougher and more stable. Connecting the circuit in this way allows the input of sufficient air pressure and energy to drive the piston. Example 3: Pneumatic system is to be designed to operate a door of public transport vehicles. (Figure 1.12). Assuming that the opening and closing of the doors are controlled by two button switches ON and OFF. When the button switch ON is pressed, the door will open. When the button switch OFF is pushed, the doors will close. Solution. Operation of pneumatic system that controls the door of vehicle Figure 1.12 Solution
Therefore, the signal for cancelling the lock should be operated by a normally open type control valve. However, to cancel the lock, the same signal must also cancel the locks on other devices, like the indication signal . Figure 1.10 shows how the normally closed type control valve  can be used to cut off the normally open type control valve  and achieve the goal of changing the signal. DIRECT CONTROL OF DOUBLE ACTING CYLINDER The only difference between a single acting cylinder and a double acting cylinder is that a double acting cylinder uses a 5/2 directional control valve instead of a 3/2 directional control valve (Figure 1.11). Usually, when a double acting cylinder is not operated, outlet ‘B’ and inlet ‘P’ will be connected. In this circuit, whenever the operation button is pushed manually, the double acting cylinder will move back and forth once In order to control the speed in both directions, flow control valves are connected to the inlets on both sides of the cylinder. The direction of the flow control valve is opposite to that of the release of air by the flow control valve of the single acting cylinder. Compared to the throttle inlet, the flow control valve is tougher and more stable. Connecting the circuit in this way allows the input of sufficient air pressure and energy to drive the piston. Example 3: Pneumatic system is to be designed to operate a door of public transport vehicles. (Figure 1.12). Assuming that the opening and closing of the doors are controlled by two button switches ON and OFF. When the button switch ON is pressed, the door will open. When the button switch OFF is pushed, the doors will close. Solution. Figure 1.12 Operation of pneumatic system that controls the door of vehicle Solution