![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
1 Introduction
In the numerical control machine tool, the manual operation panel is always indispensable, its characteristic is 1. Some input quantities are mutually exclusive, does not allow the misoperation, guarantees the request by the mechanical interlock relation; 2nd, the key on/off Use level to trigger different states, instead of using edges to trigger different states; 3. Allow multiple states to input simultaneously and respond reliably; 4. Can make the necessary prompts for the current state of the device, such as using a signal light, light two Grade tube or LCD display. Most of the existing designs use the input/output of the manual operation panel as part of the switching I/O and are controlled by a built-in or external programmable controller (PLC). The numerical control machine tool manufacturer purchases the numerical control system according to the craft characteristic of one's own machine tool, through the secondary development, forms the numerical control machine tool product whose technological performance and operation are different from each other. The vast majority of the secondary development workload lies in the design of the switching I/O. Among them, over 60% of the work is based on the design and operation of the manual operation panel [1]. In fact, the input/output of the manual operation panel is only the control signal switching I/O, and its driving capability is very low. It is a special kind of numerical control machine switching I/O. If the input/output of the manual operation panel is not differentiated from other switching I/O of the CNC machine tool, the secondary development workload of the numerical control system will be greatly increased. The manual operation panel of the CNC machine tool cannot be standardized and modularized, and its economy will also be Was greatly affected.
This paper presents an intelligent processing unit of CNC machine tool panel based on 89C51/52 single-chip microcomputer. The processing unit exchanges information with the CNC system through the standard serial port, and can display the basic state of the CNC machine tool and perform manual operation on it. This work is part of the research of the National 863 Program “Complete Digital Machine Tool and Its Key Technologies for PC Peripherals†and has been used for three-axis CNC milling machines.
2 How it works
The 89C51/52 microcontroller has on-chip ROM, 16-bit counter, and standard serial port [2]. In the 89C51/52 single-chip machine constitutes a numerical control machine panel intelligent processing unit, generally does not require external expansion ROM and RAM, one-chip I / O port corresponding to a input / output volume, if the microcontroller I / O port is not enough, you can expand. The one-chip computer checks and inputs the input with time cut off, once discovering the change of the input level, will send its corresponding new state to the numerical control system through the serial port. On the other hand, the numerical control system sends the information that needs to be displayed to the one-chip computer through the serial port. Because serial communication is used, the interface between the CNC system and the panel intelligent processing unit is standard. The information processing of the operation panel basically does not occupy the time of the CNC system CPU, and the panel intelligent processing unit itself becomes a standardized module. Figure 1 shows the schematic diagram of the intelligent processing unit of the CNC milling machine panel. In the figure, the input/output information of the CNC mill manual operation panel is roughly the following:
Figure 1 Schematic diagram of intelligent processing unit for CNC milling machine panel
1) Work mode selection: Manual/Auto/Return to origin 2) Single step feed amount selection 3) Continuous feed speed selection 4) Feedrate speed override 5) Feed coordinate selection 6) Spindle motor, pump, electromagnetic clutch brake Equivalent on/off control 7) Emergency stop 8) Pause and display 9) Feed coordinate over-travel display 10) Fault display Among them, selection of operation mode, single step feed amount and continuous feed speed, and feedrate override Select switch 1 and switch 2 respectively to switch between different states. The state of the same transfer switch control is mechanically interlocked to avoid the simultaneous connection of two or more interlocked states due to misoperation. The remaining input/outputs in Figure 1 are directly controlled by the microcontroller's I/O port to ensure that multiple states are reliably input/output at the same time.
3 system software
89C51/52 SCM CNC machine tool panel intelligent processing unit power-on reset initialization, enter the interrupt working state, allowing timer interrupts and serial interrupts. In timing interruption, it will detect whether there is any change in the input status and send the changed input status to the CNC system through the serial port; the CNC system needs to send the information displayed by the manual operation panel from the serial port to the MCU, and the serial interrupt service is provided by the MCU. The program makes corresponding treatment, its block diagram is shown as in Fig. 2, among them Fig. 2 (a) is the main program block diagram, Fig. 2 (b) is the timing interrupt service routine block diagram, Fig. 2 (c) is the serial interrupt service routine diagram .
Figure 2 block diagram
The power-on reset and initialization of the microcontroller can be completed in a very short time, and the initialization of the CNC system takes a long time. When the initialization of the CNC system is not completed, the serial communication cannot work. Therefore, after the initialization of the main program of the single-chip microcomputer, it is necessary to wait for the CNC system to send the “READY†signal from the serial port and start the operation panel after receiving the “READY†signal. The input/output is controlled.
In the timed interrupt service routine, the status of each key is checked one by one. If it is found that the status of a certain key has changed, the new status is sent from the serial port to the CNC system and the interrupt service routine is exited. Otherwise, all keys are checked. Exit the interrupt service routine. In order to detect the change of the key state, the original state of the key must be stored in the memory, 00H indicates that the key is in the ON state, and FFH indicates that the key is in the OFF state. When reading a key is in the ON state, first determine the value in the memory is 80H or <80H, if the value in the memory is 80H, the key is originally in the disconnected state, if it is reduced by 1 and then the FCH is stored, Memory, if <FCH, it means that the read key is turned on three times in a row, that is, the state of the key changes from disconnected to turned on, clearing the memory to 00H (on state); if the value in the memory is <80H, indicating key Originally in the ON state, the state of the key has not changed, the memory is cleared to 00H (due to various disturbances, the memory may be a number of <03H). When reading a key in the disconnected state, it is still first to determine whether the value in the memory is 80H or <80H. If the value in the memory is 80H, the key is originally in the disconnected state, the state of the key is not changed, and the memory is set. It is FFH (the memory may be a FCH number due to various disturbances); if the value in memory is <80H, the key is originally in the ON state, and if it is incremented by <04H, it will be stored in the memory. 04H indicates that the key is disconnected three times in a row, ie, the state of the key changes from ON to OFF, and the memory is set to FFH (ON state). This can effectively avoid erroneous judgment due to key jitter and other disturbances. These processes can be accurately described using the state transition shown in FIG.
Figure 3 State transition diagram
4 Conclusion
This paper presents a new intelligent processing unit based on 89C51/52 single-chip numerical control machine tool panel. The following conclusions can be obtained from theoretical analysis and practical application:
(1) The panel intelligent processing unit meets the functional requirements of the manual operation panel of the numerically-controlled machine tool, and the hardware and software are rationally designed with high reliability;
(2) Using serial communication, making the manual operation panel a simple and standard module;
(3) This paper presents a software algorithm to eliminate key jitter. The algorithm is reliable and simple.
(4) The panel intelligent processing unit has very good expansibility, it can be very convenient to expand single-point input / output ports, but also to drive digital or liquid crystal display.
Floor Decking Machine,Hydraulic Machine,Decking Machine
Unovo Machinery Co., Ltd. , http://www.jsformingmachine.com