An example to illustrate the comparison between bus-in-one computer and traditional pulse control
Before that, we need to understand two concepts: what is FA network control, what is traditional impulse control, FA network control (Factory Automation Network), also known as bus network control, which refers to the interconnection of equipment and equipment, transmission of a large amount of information, layered structure. Fig. 1 is the overall framework of network control; traditional impulse control, that is, PC (computer, PLC, single chip computer). The driver amplifies the pulse signal to drive the motor to turn.
Compared with traditional pulse control, FA network control has great advantages. Here, the application of two control modes in large music fountains is compared and illustrated. To make a large-scale music fountain project will involve a variety of equipment control, including stepping motor, color lights, switching volume, sprinkler and other equipment. In order to save space, this paper mainly uses two control methods to control the largest amount of digital sprinkler in the project. Large-scale music fountain project will use hundreds or even thousands of digital sprinklers, multiple sprinklers simultaneously linkage spray water column, showing a beautiful picture, each sprinkler is controlled by a precise positioning stepping motor, then the control of stepping motor will involve traditional pulse control and bus control.
Traditional pulse control:Traditional pulse control schemes usually send pulses to drivers from large control cabinets with multiple pulse output interfaces. This control cabinet has signal processing capability. The driver amplifies the pulse signals to drive the motor to run, so as to achieve the overall linkage effect. Fig. 2 is the overall structure of the traditional control scheme.
There are many defects in this control mode: 1. Because of the large number of sprinklers, a large number of drivers are needed, which leads to a large number of pulse output interfaces on the control cabinet. 2. The volume of the whole control cabinet appears very large. 2. The area of the large music fountain project is very wide. The control cabinet and the driver control cabinet are placed in the control room, so the distance between the driver and the motor will be larger. Far away, too long motor wire will lead to strong current oscillation, which will lead to driver damage or serious reduction of torque, so ordinary drivers can not normally use 3. Long-distance transmission requires large cross-sectional conductors, coupled with the number of traditional schemes to do more than a large number of transmission conductors. Take 100 sprinklers in a project as an example, the average of eachdriver to the motor. The distance is 350m, the driver drives four-wire stepper motor, and 140000m is needed only to drive the wire in one project, which makes the whole control system very complicated.
FA network control:Using FA network control and small stepper motor drive controller can optimize the project to a great extent. FA network control transmits communication signals from the upper computer (usually PLC) to the controller. The controller converts communication signals to pulse to driver. The driver drives the motor to run. The overall structure of FA network control is shown in figure 3. At present, a few excellent enterprises in the market have introduced integrated products of drive, control and motor. Fig. 4 is a PMC007 small stepper motor driver of a company. The upper computer only needs one communication wire to control a large number of motor linkage. Therefore, the upper computer only needs several bus interfaces to reduce the size of the upper computer. Because the driver and motor are integrated, the driver does not need to have high current and high current. Voltage characteristics, ordinary drivers can meet the requirements, while eliminating a large number of drivers to the motor wire
Conclusion:Compared with traditional pulse control, FA network control in large-scale music fountain project has the following advantages: 1. Reducing the volume of upper body 2. Optimizing project wiring to a great extent 3. Reducing the difficulty of troubleshooting 4. Easy to change the layout in the later stage 5. Reducing material cost 6. Reducing the difficulty of construction.