Although many relays, timers and counters are often used in the ladder diagram programs used by LS PLC, LS PLC does not have these hardware physically, but uses memory and program programming methods to make logic control modifications, and connects external mechanical equipment through output components for physical control. As a result, the hardware space required for the controller can be greatly reduced. In fact, the PLC performs the ladder diagram program by reading the ladder diagram code into the CPU by scanning method line by line, and then performs the control operation.
In the whole scanning process, there are three major processes, "Input Status View", "Program Fulfillment", and "Output Status Update" are explained as follows:
Process 1 "Input Status Viewing":P LC first checks the status of each point switch or sensor connected to the input element (1 or 0 means on or off) and writes its status to the corresponding position Xn in memory.
Process 2 "Program Fulfillment": The ladder diagram program is taken into the CPU line by line for calculation, and if the contact status of the required input is required in the program fulfillment, the CPU will be queried and taken out directly from the memory. The calculation result of the output coil is stored in the corresponding position in the memory, and is not reflected to the output Yn for the time being.
Process 3 "Output Status Update": Update the output status of Process 2 to the PLC output contact, and return to Process 1. These three processes are called the scanning cycle of the PLC, and the time required to complete is called the reaction time of the PLC. After each program execution and before the next program execution, the output and input status will be updated once, so this operation method is called "program end regeneration" at the output and input terminals.
|
More on that
|
The difference between overload and overcurrent of the inverter
(1) The maintenance objectives are different
Overcurrent is mainly used to maintain the inverter, whereas overload is mainly used to maintain the motor. Because the capacity of the inverter sometimes needs to be increased by one or even two gears than the capacity of the motor, in this case, the inverter is not necessarily overcurrent when the motor is overloaded.
...
|
|
Energy-saving method of ventilator inverter - LS power generation
high-power
Although some inverters are fan type inverters, but it is a low-power fan inverter, such an inverter does not have the effect of energy saving, and it is necessary to achieve energy saving must be a high-power inverter, in addition to the high-power fan inverter, it is necessary to meet its ...
|
|
Failure analysis of electromagnetic system of LS power production contactor
(1) The core noise is large: it is normal for the electromagnetic system to produce a slight humming sound during operation, if the sound is too loud or abnormal, it can be judged that the electromagnetic system has a problem, and there are three reasons:
(1) Poor contact between the armature and the core or tilting of the armature. After repeated collisions between the touch of the armature and the core, ...
|
|
The main structure of LS power AC contactor
The operating principle of the contactor is: when the contactor coil is energized, the coil current will generate a magnetic field, and the generated magnetic field will make the static iron core attract the moving core with electromagnetic attraction, and drive the communication contactor point action, the normally closed contact is disconnected, and the normally open contact is closed, and the two are linked. When the coil is de-energized ...
|
|
Inverter circuit structure - LS generates electricity
The main circuit is the power replacement part of the power supply for the asynchronous motor, and the main circuit of the inverter can be roughly divided into two categories: the voltage type is to change the DC of the voltage source to the communication of the DC port of the inverter, and the filter is the capacitor. The current type is to change the DC of the current source to the communication ...
|
|
Advantages of universal inverter - LS produces electricity
Universal inverters are characterized by their versatility. With the development of inverter technology and the continuous expansion of market demand, general-purpose inverters are also developing in two directions: low-cost simple general-purpose LS inverters and high-performance and multi-functional general-purpose inverters. They have the following characteristics:
...
|
|
Introduction to the working principle of LS electric molded case circuit breaker
Molded case circuit breakers are also known as equipment circuit breakers, all parts are sealed in plastic housings, auxiliary contacts, undervoltage trippers and shunt trippers are modular. Because of the very compact structure, the molded case circuit breaker is basically impossible to maintain. It is mostly manually operated, and the large capacity ...
|
|
Introduction of LS electric power contactors
How LS Contactor Works:
Generally, after the contactor coil is energized, the entire coil current will generate a magnetic field, which will make the core inside have electromagnetic attraction to attract the core, and let their communication contactor point action normally closed contact disconnect, or close, which ...
|
|
LS power production contactor application
LS touchers are divided into AC touchers (voltage AC) and DC touchers (voltage DC), which are used in electricity, power distribution and consumption. Toucher broadly refers to the electrical appliances that use the current flowing through the coil to generate a magnetic field in industrial electricity, so that the contacts are closed, so as to control the load.
...
|
|
Wiring of the main circuit of the inverter - LS generates electricity
1. The power supply should be connected to the R, S, and T terminals at the input end of the inverter, and must not be connected to the output terminal (U, V, W) of the inverter, otherwise the inverter will be damaged. After wiring, it is necessary to clean the trivial wires, which may cause abnormalities, failures and problems, and it is necessary to always keep ...
|
|
Selection of AC contactors in the field of building electrical - LS power production
1. The series and parallel connection application of contactors Many electrical equipment are single-phase loads, so several poles of multi-pole contactors can be used in parallel. Such as resistance furnaces, welding transformers, etc. When using several poles in parallel, a smaller capacity contactor can be used. However, it must be noted that after parallel ...
|
|
Motor & Electrical Control Technology Tips - LS Electricity Production
1. Low-voltage electrical appliances: refers to electrical appliances that play the role of on-off, maintenance, control or regulation in circuits with a rated voltage of 1200V and a rated voltage of 1500V and below.
2. Main electrical appliances: electrical appliances used to send control instructions in the automatic control system.
3. Fuse: ...
|
|
After the contactor is energized, the start button continuously engages and disconnects ?—— LS generates power
What is the reason why the contactor keeps engaging and disconnecting by pressing the start button after the AC contactor is energized?
In my personal opinion, most of the situation is caused by the wrong coil voltage of the replacement AC contactor, or the purchase of ...
|
|
Quickly locate switching power supply faults
Switch Mode Power Supply (SMPS) will cause the base of the switch tube to fail to get the switching pulse and intermittently operate due to the short circuit of the load, the failure of the self-vibration circuit and the loss of control of the protection circuit, which makes it difficult to locate the shortcomings of SMPS. Difficult to repair the work ...
|
|
Communication control of inverter - power inverter
The communication control of the inverter is more complicated, so it is listed separately.
The communication control of the inverter is a control method for the operation, speed regulation and status indication of the inverter through the communication interface of the inverter.
...
|
|
The difference between inverter and servo - LS produces electricity
An important difference between servo and frequency conversion is that frequency conversion can be without encoder, while servo must have an encoder for electronic commutation.
1. What the two have in common:
The skill of communication servo itself is the learning and application of ...
|
|
Introduction to wiring problems - LS power generation
1. Wiring of fire emergency lighting
Generally, the flame retardant wire is used to wear the metal pipe and the thickness of the protective layer is ≥ 30mm.
|
|
LS takes you to understand the inverter in the inverter
Contrary to the rectifier, the inverter converts the DC power into the communication power of the required frequency, and the 3-phase communication output can be obtained by turning on and off the 6 switching devices at the confirmed time. Take a voltage-type PWM inverter as an example to show the switching time and voltage waveform.
Control circuit ...
|
|
Relationship between motion control and frequency converter
Motion control has a significant period characteristic, it is a combination of a variety of high-tech to push industrial automation, office automation and home automation to a higher stage. At present, the motion control is mainly composed of three parts: inverter, motor and controller.
...
|
|
The touch screen controls the inverter steps
1. The touch screen is controlled by PLC inverter
1. At present, the general control of the inverter needs to use PLC to communicate with the inverter, read the information of the inverter, and then the touch screen communicates with the PLC in order to complete the control of the inverter to start, stop, and monitor the operation of the inverter.
|
|
Contact
working hours
