I. System hardware module and interface definition
Generally speaking, the elevator control system is divided into two parts, elevator well and elevator car two plate can control the movement of the elevator, and the power of the elevator is composed of components such as motor. The control signals on each floor of the elevator shaft and the control signals in the elevator car are controlled by a series of operations to control the speed and direction of movement of the elevator.
1. Elevator Shaft
An elevator well on each floor has an entrance (exit), and the entrance will be equipped with control buttons and display devices, the current elevator is generally through each layer of "upstream" and "down" button to issue instructions, and each layer has led digital tube display to show the elevator car is currently in the floor, It also displays information such as the stop at the floor where it was located, and arrows to show the direction of its movement. At the same time, you should set the position switch on each floor to obtain the current position information of the elevator, so as to be able to display on the LED digital tube display, and the elevator in the floor after the stop to open the external elevator door. Then according to the actual situation should be set at each level:
(1) "Upstream" and "downlink" button, request the command input interface;
(2) LED digital tube display, information output interface;
(3) position sensor switch, information input interface;
2. Elevator car
Elevator car interface is different from the above, the car has 7 floors per layer of the corresponding keys, while there are "open door", "close" key, there should be security for the Help button. Also, the display of the current floor of the LED digital tube display, the role is to show the current floor of the elevator, through the flashing surface will be parked in the open door, through the arrows to show the direction of movement. Finally, in order to ensure safety, for the door is completely closed to set a position switch, only when the door is completely closed to start the motor drive elevator movement, and when the elevator stops steady, the door key to the command response. So design the interface according to the actual situation:
(1) 7 levels of the key, the whole command input interface;
(2) "Open Door", "close" button, local command input interface;
(3) SOS button, call command input interface;
(4) Speed sensing or position switch, information input interface;
(5) Door completely off/close position switch, information input interface;
(Command instruction is higher than the request instruction, that is, after the command order takes effect, only the request instruction of this trip can be answered by the elevator, the other request commands are helpless; when there is no command, the request is answered by the answer of the reply)
3. Powerplant
Power plant from the AC servo motor or unit composition, the positive and negative motor to drive the elevator up and down, the instructions of the PLC control motor Movement, the interface of the power plant is the command input interface, used to input the start and stop, up/down motion to how many layers of instructions, and these instructions need to be implemented by the motor speed to achieve, So in addition to the motor also need to stabilize the speed of the circuit to control the speed of the motor.
Two. Functional design of the system
1. Information Display function
Each LED digital display shows the current floor of the elevator, as well as the direction of movement of the elevator, as well as flashing means that the elevator will be parked in a certain level; each command key should also correspond to a light indicating that the instruction responds to a normal response.
2. Meeting the motion instructions of the elevator car
PLC receives elevator car floor instructions, by comparing the current floor to determine the direction of movement, it is worth noting that in the elevator internal command priority is the same, so that the target matching principle to execute the directive, that is, in the current direction of movement, first to the command floor first stop, It can also respond to the external request instruction of the elevator passing through, but does not respond to other external commands; Until the elevator reaches the last command floor, its instruction interface is open to all external requests.
3. Partial meeting of the elevator outside each layer of the stop-in instructions
From the previous one, only in a trip to the floor of the elevator to respond to the request instruction; In addition, in the absence of internal elevator instructions, the external instructions are executed according to the answer, that is, the direction of movement toward the first press the external command key of the floor, but also can respond to the instructions through the floor.
4. Security Function Details
(1) Outside, in the elevator did not reach the floor or not in the floor stop, the external elevator door will not open;
(2) Inside, the elevator does not reach the designated floor and stop steady, the internal elevator door will not open;
(3) When the elevator is overloaded or closed, internal and external elevator doors will not close;
(4) The distress signal leads to the duty room or other security Department of the building;
(5) When the motor suddenly loses power, the emergency power supply or emergency braking device can be activated immediately.
Three. Overall brief
The control interface is connected to the control end of the PLC, and the output of the PLC is connected to the control parts of the motor, thus constituting a whole circuit, and the information acquisition and display can constitute a display loop separately, but the obtained floor information should be entered into the PLC to compare and determine the direction of the elevator movement. Elevator safety function through some other circuit to achieve, involving the function of elevator motion should also be connected to the PLC control circuit, such as elevator door opening and closing, elevator emergency braking and so on. The main body of this project is the control circuit of elevator movement, which is the main goal that we should study, realize the correct control of elevator movement, the other functions are much easier.
Preliminary plan for elevator control project of machinery building