1. Check the circuit according to the drawing (without power transmission)
The drawings of the general PLC system include two parts: the drawings in the cabinet and the drawings outside the cabinet; The drawing in the cabinet refers to the wiring diagram inside the cabinet; The out-of-cabinet drawings are the wiring diagrams of all electrical cabinets.
This part needs to be checked for;
1. Whether the drawing design is reasonable, including the capacity of various components, etc.
2. Check whether the components are connected in strict accordance with the drawings according to the drawings.
During this process, the most important thing to pay attention to is to check the power supply:
1. Make sure there is no short circuit in the circuit.
2. Make sure that the strong and weak currents are not mixed together; Because the PLC power supply is 24V, once the 220V is connected to the PLC due to the wrong wiring, it is easy to burn the PLC or expansion module.
2. Check the external circuit of the PLC, which is commonly known as "dotting"
After the power supply is confirmed, the power is transmitted, and the input and output points are tested, which is commonly known as "dotting", and the test IO points need to be tested one by one, including the operation button, the emergency stop button, the operation indicator light, the cylinder and its limit switch, etc., the specific method is that one person operates the button on the field side, etc., and the other person measures and monitors the input and output signals in the PLC; For large systems, test sheets should be established, i.e., marked after testing. If it is found that there is a wiring error during the construction process, it needs to be dealt with immediately.
In this step, it should be noted that it is necessary to clear the program in the PLC or disable the program after backing up the program to avoid the operation of the equipment caused by the test.
3. Check the mechanical structure and test the motor load
This step needs to check whether the mechanical structure is tightened, etc., whether the motor load is properly protected to avoid accidents caused by accidents, and after the inspection is completed, it is necessary to manually test the operation of the equipment, such as forward and reverse motors, whether the circuit is intact and electrified, and the inverter class sets the corresponding parameters and optimizes the motor, static identification or dynamic identification, etc.
It should be noted here that for some special loads, such as those that move up and down vertically, they need to be carried out by professionals to avoid test accidents due to improper control.
4. Debugging manual mode/semi-automatic mode and related logical relationships
After testing both the IO point and the load side, the next step is to debug in manual mode. The manual mode here can also be called semi-automatic mode, which does not directly press the solenoid valve or contactor by hand, but refers to the drive of the device through the button or HMI button, etc., which corresponds to the automatic state. The manual mode of testing can decompose the automatic mode according to the person's wishes, which is convenient for the test procedure.
The most important thing in this process is to test the safety function, i.e. to test whether the safety functions such as emergency stop, safety light curtain, etc., play a corresponding role in the operation of the equipment.
5. Debug the automatic mode according to the production process
After the semi-automatic commissioning is completed, the automatic work can be further commissioned. This link is the most important, it is necessary to test various interlocks according to the production process, including logical interlocking, safety interlocking, etc., and to test several more working cycles to ensure that the system can work correctly and continuously.
6. Testing of special processes
In addition to logic control, there are many extended functions in the PLC system, such as PID control, etc., when these logic debugging is basically completed, you can start to debug analog and pulse control. The most important thing is to select the appropriate control parameters. Generally speaking, this process is relatively long. It is necessary to adjust patiently, and the parameters should also be selected in a variety of ways, and then the best one should be selected. For some PLCs, the PID parameters can be obtained by autotuning. However, this self-tuning process also takes a considerable amount of time to complete.
7. Complete all the above steps
The whole debugging is basically complete. The next step is the pre-production step, pre-production is the pre-production work test, in this stage can cooperate with the production to carry out some special tests, such as whether the production rhythm is satisfied, whether the safety function can still work under the load, etc., generally continuous production can be delivered after a certain period of time.
|
More on that
|
Megmeet PLC - What is the difference between PLC and servo control system
1. The meaning of the representation is different:
PLC is the abbreviation of planar optical waveguide (technology), the so-called planar optical waveguide, means that the optical waveguide is located in a plane.
A servo control system is a feedback control system used to accurately follow or reproduce a certain process.
|
|
Megmeet PLC - how the PLC communicates with the host computer
The PLC communicates with the host computer, and BlandC is used to write the communication program between the host and the PLC, and the COM1 port must be initialized, the baud rate is 9600bps, and the parity check bit adopts even check, and the seven-digit valid data is used.
When the computer receives the response character ACK from the PLC, it ...
|
|
The principle of Megmeet plasma cutting and its characteristics
5) PLASMA
The principle of plasma cutting is: arc discharge between the base metal (including the nozzle in the cutting torch) and the electric in the cutting torch, and use the discharge heat energy to make the compressed gas produce a high-temperature and high-speed plasma arc to fuse the cutting method of the base metal. The small hole of the nozzle ...
|
|
Megmeet drives – what are the components of a drive?
The inverter is composed of a main circuit, a rectifier, a flat wave circuit, and an inverter.
1) Main circuit:
The main circuit is the power conversion part that provides voltage regulation and frequency regulation power supply for the asynchronous motor, and the main circuit of the inverter can be roughly divided into two categories: the voltage type is the DC ...
|
|
Common faults and solutions of Megmeet inverter
1. Leakage protection switch
Phenomenon: The leakage protection switch of the equipment is activated when the inverter is powered on or running
Measures:
When the inverter drives the motor, the leakage value is larger than that of the non-inverter system, and the leakage protection value of the leakage protection switch is required to be 150mA and above, and the action delay is ...
|
|
Megmeet PLC - Comparison of the advantages of PLC and DDC in building automation systems
1. Application field: The initial design goal of PLC is only to replace complex relay circuits, and DDC is originally only used in industrial automation instruments: PLC emphasizes versatility, DDC emphasizes specificity: PLC is used in the field of industrial control, and DDC is used in professional building systems.
2. Structural differences ...
|
|
Megmeet PLC – the three basic process contents of PLC work
1. Input processing
Input processing is also called input sampling. In this phase, the through-end state of all input terminals is read sequentially, and the read information is stored in the corresponding image register in memory. Here the input image register is flushed. Then the program execution phase begins. In the execution of the procedure ...
|
|
Megmeet inverters – Routine maintenance of high-voltage inverters requires precautions
1. The operating ambient temperature of the inverter (mainly refers to the air temperature of the air inlet of the power unit cabinet) requires a minimum ambient temperature of -5 °C and a maximum ambient temperature of 40 °C. In order to improve the reliability and extend the service life of the drive, check the following items:
Air conditioning and refrigeration ...
|
|
Megmeet inverter - precautions for inverters at high temperatures
1. Carefully monitor and record the display parameters on the man-machine interface of the inverter, and reflect the abnormality immediately;
2. Carefully monitor and record the ambient temperature of the frequency conversion room, and the ambient temperature should be between -5 °C and 40 °C. The temperature rise of the phase-shifting transformer should not exceed 130°C;
3. Summer ...
|
|
Megmeet welding machine - an introduction to the advantages and disadvantages of resistance welding
Advantages of resistance welding:
1。 When a nugget is formed, it is always surrounded by a ring of plastic, the molten metal is isolated from the air, and the metallurgical process is simple
2。 The heating time is short, the heat is concentrated, the heat affected zone is small, and the deformation and stress are small. In general, there is no need to arrange calibration and heat after welding.
|
|
Megmeet welding machine - failure and maintenance method of DC welding machine
1. Fault phenomenon: light voltage abnormal indicator
Cause: Due to the slow start-up action, the switch contact is not synchronized.
Solution: You can turn the device off and on again.
2. Fault phenomenon: the fan does not rotate, and the abnormal voltage indicator light is lit together
Causes ...
|
|
Megmeet PLC - What are the main components of PLC control cabinet?
1. Air switch
Air switch is also called air circuit breaker, referred to as air open, is an indispensable component of the control cabinet, usually from the outside into the cabinet of power supply, must go through the air open, in order to reach the inside, the function of air open in addition to the power supply, more as short circuit protection and overload protection...
|
|
Megmeet inverter – the energy-saving principle of low-voltage inverter
Inverter energy saving
The energy saving of the inverter is mainly manifested in the application of fans and pumps. In order to ensure the reliability of production, all kinds of production machinery are designed with power drive, and there is a certain amount of surplus. When the motor cannot operate at full load, in addition to meeting the power drive requirements, ...
|
|
Failure and maintenance of welding machines
1. Damage to the welding power supply. Due to the high current and high voltage during welding, when the welding current exceeds 20% of the rated value, overcurrent protection will appear, so that the circuit will automatically cut off the power supply. In addition, if the welding time is too long, it can also cause overcurrent. Therefore, we should try our best to ...
|
|
Megmeet Inverter - Precautions for the Use of Inverter (11-21)
11. For the occasion when the inverter drives the ordinary motor for constant torque operation, long-term low-speed operation should be avoided as much as possible, otherwise the heat dissipation effect of the motor will become worse and the heating will be serious. If long-term operation at low speed constant torque is required, a variable frequency motor must be selected.
12. For the promotion of negative ...
|
|
Megmeet PLC - the characteristics of the working process of PLC
1. The PLC adopts the mode of centralized sampling and centralized output, which can reduce the influence of external interference.
2. The working process of PLC is the process of cyclic scanning. The duration of the cyclic scan depends on the speed of execution of the instructions and the length of the user's program.
3. Output to input ...
|
|
What are the characteristics of Megmeet PLC - PLC working process?
(1) The PLC adopts the working mode of centralized sampling and centralized output, which reduces the influence of external interference.
(2) The working process of PLC is the process of cyclic scanning, and the length of cyclic scanning time depends on the speed of instruction execution, the length of the user program and other factors.
(3) Output ...
|
|
Megmeet inverter - 5 precautions for the use of inverter
1. The circuit board inside the inverter belongs to precision electronic components, which needs to be moisture-proof and dust-proof, and the temperature and humidity are not too high, and cannot be installed on the bare wall, so the inverter should be installed in the middle of the control cabinet; The inverter should be installed vertically, and the installation should be avoided directly above and below ...
|
|
Megmeet drives – safety precautions for the installation of drives
When the inverter is installed and wired;
Note: When more than two inverters are installed in the same cabinet, please pay attention to the installation position and spacing to ensure the heat dissipation effect.
Dangerous:
1. It should be operated by professional electrical engineering personnel, otherwise there is a risk of electric shock.
2. Please make sure before wiring...
|
|
Megmeet PLC maintenance inspection
PLC maintenance and inspection steps:
1. Check and make sure the mains power is on (120 VAC)
2. Check the available 24V power supply
3. Identify problem areas. It is recommended that peak currents cover this error code, a control method consisting of multiple components distributed over an area or process.
|
|
Contact
working hours
