2.2.3 Multi microprocessor architecture system
In a multi microprocessor architecture CNC device with two or more CPUs, multiple operating systems effectively implement parallel processing.
(1) Basic function module of CNC device with multi microprocessor structure
Table 2-5 describes the basic functional modules of a multi microprocessor architecture in detail.
Table 2-5 Basic functional modules of multi microprocessor architecture
| Serial number | Basic function module | Detailed description |
| 1 | CNC device management module | The CNC device management module implements the functions required to manage and organize the entire CNC system work process. Such as system initialization, interrupt management, bus arbitration, system error identification and handling |
| 2 | CNC device interpolation module | This module completes pre processing before interpolation such as decoding, tool compensation calculation, coordinate displacement calculation, and feed speed processing; Then, interpolation calculation is performed to provide a quantitative position for each coordinate axis |
| 3 | Position control module | The interpolated coordinate position given value is compared with the actual position value measured by the position monitor to perform automatic acceleration and deceleration, return to the base point, servo system hysteresis monitoring, and drift compensation. Finally, an analog voltage for speed control is obtained to drive the feed motor |
| 4 | PLC module | Some auxiliary functions in part processing and signals from the machine tool are logically processed in the PLC module to achieve the connection between various functions and operating modes, start and stop of machine tool electrical equipment, tool exchange, turntable indexing, counting of workpiece quantity and operating time, etc |
| 5 | Operation and control dataOperation and control data I/O and display module | This module implements the input/output of part processing programs, parameters and data, various operating commands, and various circuits required for display |
| 6 | Memory module | This module refers to a main memory for storing programs and data, or a shared memory for data transfer between functional modules |
(2)Advantages of multi microprocessor architecture
Compared to single microprocessor based CNC devices, multi microprocessor based CNC devices have the following advantages, as shown in Table 2-6.
Table 2-6 Advantages of Multimicroprocessor Architecture
| Serial number | Advantages | Detailed description |
| 1 | Fast computing speed, high cost performance ratio | In a multiprocessor architecture, each microprocessor performs a specific function, is independent of each other, and works in parallel, resulting in high computational speed. It adapts to the requirements of multi-axis control, high feed speed, high accuracy, and high efficiency of numerical control. Due to the shared resources of the system, it has a high cost performance ratio |
| 2 | Strong adaptability and easy expansion | Multi microprocessor CNC devices mostly adopt modular structures. The microprocessor, memory, and input/output control can be respectively made into plug-in boards, or they can be formed into independent hardware modules. The corresponding software is also a modular structure, which is solidified in the hardware module In this way, the CNC device can be built in blocks, which has good adaptability and scalability, and is also convenient for maintenance |
| 3 | High reliability | Due to the independent completion of a task by a functional module of a multiprocessor, if a functional module fails, the other modules will continue to work as usual without causing the entire system to collapse. Simply replacing a normal module will solve the problem and improve system reliability |
| 4 | Hardware is easy to organize large-scale production | General hardware is universal and easy to configure. As long as new software is developed, different CNC devices can be formed, which is convenient for organizing large-scale production, ensuring quality, and forming batches |
