Based on the understanding of the program structure and programming methods, it is necessary to actually write the PLC program. The PLC control system design needs to go through the following process.
(1) Analyze the controlled object and propose control requirements
Detailed analysis of the process and working characteristics of the controlled object, understanding the cooperation between the controlled object machine, electricity and liquid, proposing the control requirements of the controlled object to the PLC control system, determining the control plan, and drafting the design task book.
(2) Determining input/output devices
According to the control requirements of the system, determine all the input devices (such as buttons, position switches, transfer switches and various sensors) and output devices (such as contactors, solenoid valves, signal indicators and other actuators) required by the system. Etc.) to determine the input/output devices associated with the PLC to determine the number of I/O points for the PLC.
(three) choose PLC
PLC selection includes selection of PLC model, capacity, I/O module, power supply, etc. See section 2 of this chapter for details.
(4) Allocating I/O points and designing PLC peripheral hardware lines
1. Assign I/O points
Draw the connection diagram or correspondence table of the I/O point of the PLC and the input/output device. This part can also be performed in step 2.
2. Design PLC peripheral hardware circuit
Draw the electrical circuit diagram of the rest of the system, including the main circuit and the control circuit that does not enter the programmable controller.
The electrical schematic of the system is composed of the I/O connection diagram of the PLC and the peripheral electrical circuit diagram of the PLC. The hardware electrical circuit of the system has been determined so far.
(5) Program design
Programming
According to the control requirements of the system, the PLC design is designed using appropriate design methods. The program should meet the system control requirements as the main line, and write the programs that realize the various control functions or sub-tasks one by one, and gradually improve the functions specified by the system. In addition to this, the program should usually include the following:
(1) Initialization procedure. After the PLC is powered on, it is necessary to do some initialization operations to make necessary preparations for startup to avoid system malfunction. The main contents of the initialization program are: clearing certain data areas, counters, etc., restoring the data required in some data areas, setting or resetting certain relays, displaying some initial states, and so on.
(2) Procedures such as detection, fault diagnosis and display. These programs are relatively independent and are usually added when the programming is almost complete.
(3) Protection and chain procedures. Protection and chaining are indispensable parts of the process and must be carefully considered. It can avoid control logic confusion caused by illegal operations.
2. Program simulation debugging
The basic idea of ​​program simulation debugging is to simulate the actual state of the scene in a convenient form and create the necessary environmental conditions for the operation of the program. According to the way of generating the on-site signal, the simulation debugging has two forms: hardware simulation method and software simulation method.
(1) The hardware simulation method uses some hardware devices (such as using another PLC or some input devices, etc.) to simulate the signals generated in the field, and these signals are hardwired to the input of the PLC system, and its timeliness Stronger.
(2) The software simulation method is to write another set of simulation program in the PLC, and the simulation provides the on-site signal, which is simple and easy to implement, but the timeliness is not easy to guarantee. In the simulation debugging process, the segmentation debugging method can be used, and the monitoring function of the programmer is utilized.
(6) Hardware implementation
The hardware implementation mainly involves the design and on-site construction of hardware such as control cabinets (stages). The main contents are:
1) Design the electrical layout and installation wiring diagram of the control cabinet and console.
2) Design an electrical interconnection diagram between the various parts of the system.
3) Perform on-site wiring according to the construction drawings and conduct detailed inspection.
Since the programming and hardware implementation can be performed simultaneously, the design cycle of the PLC control system can be greatly shortened.
(7) Online debugging
Online debugging is a further online tuning of the program that is debugged through simulation. The online debugging process should be carried out step by step. The PLC is only connected to the input device, connected to the output device, and then connected to the actual load. If the requirements are not met, the hardware and program are adjusted. Usually you only need to modify some programs.
After all debugging is completed, the test run is delivered. After a period of operation, if the work is normal and the program does not need to be modified, the program should be cured into the EPROM to prevent the program from being lost.
(8) Organizing and writing technical documents
Technical documents include design specifications, hardware schematics, installation wiring diagrams, electrical component schedules, PLC procedures, and instruction manuals.
LED Highbays Is one of the most important lamps, it can use electricity and save money.Large commercial Spaces can generate a return on investment in products with a useful life of 5 years in 18 months. LED Highbays can eliminate the expensive maintenance cost of LED 50,000 hours of life, and the operating cost is more than 50% lower than traditional metal halides.LEDER is Suitable for all occasions.1-10v dimming means you can choose between automatic standby technology or the latest daylight capture technology to increase your power savings.LEDER has intelligent sensors ensure that the lights are not completely on when not needed.More importantly,LEDER has waterproof IP67 grade,which can be used with rain.
• Highly efficient
• 50,000 hour expected lifetime
• 1–10V dimming to support daylight harvesting and occupancy sensors
• Industrial strength ratings against impact, dust and moisture
LED High Bay Light
LED High Bay,High Bay Lights,LED Warehouse Lighting,High Bay LED Shop Lights
JIANGMEN LEDERLIGHT LIGHTING Co.,LTD , https://www.lederlight.com