1. PLC input and output
A small PLC controls a complex system with agility, and what can be seen is the upper and lower rows of staggered input and output relay terminals, corresponding lamps and PLC numbers, just like a piece of integrated electricity without dozens of feet. If any ego does not look at the diagram to repair the defective equipment, it will be helpless, and the speed of finding the defect will be extraordinarily slow. In view of this environment, we make a table according to the electrical diagram, paste it on the console or control cabinet of the equipment, and indicate the electrical symbol corresponding to the number of each PLC input and output terminal, the Chinese name, that is, the function statement of each pin of the same integrated electricity. With this I/O form, an electrician who understands the operation process or the ladder diagram of the equipment will be able to open it for maintenance. But for those electricians who don't understand the operation process and can't read the ladder diagram, they need to make another table: PLC input and output logic function table. This representation clarifies the logical correspondence between the input back (trigger element, contact contact element) and the output back (implementation element) during the operation of most departments. Practice has proved that if you can skillfully operate the input-output correspondence table and the input-output logical utility meter, repair the electrical defects, and do not have drawings, you can also be at ease.
2. Input back for overhaul
To distinguish the black and white of a button, limit, line, etc., you can press the button (or other input contact) in the PLC power-on environment (preferably in a non-running shape to prevent the equipment from malfunctioning), then the corresponding PLC input point terminal and the common end are short-circuited, and the PLC input light corresponding to the button is on, declaring that the button and the line are general. If the light is not on, it may be twisted, the wire contact is poor, or the wire is broken. If further judgment, if the twist is good, then use a meter pen of the multimeter, one end is connected to the common end of the PLC input terminal, and the other end is to contact the corresponding PLC input point (the above operation should be careful, never touch the 220V or 110V input terminal). At this point, the light is on, and the declaration line has a drawback. If the light does not turn on, it means that the PLC input point has been damaged (this environment is rare, generally caused by strong electrical invasion).
3. Output back and overhaul
Regarding the PLC output point (here only the relay output type), if the light corresponding to the action target is not lit, under the determination of the PLC operation shape, then the PLC input and output logic function of the declaration of this action target is not satisfied, that is to say, the input back is short, according to the previous mention, check the input back. If the corresponding light is on, but the corresponding implementation components such as solenoid valve and contactor do not move, first check the solenoid valve control power supply and safety device, the most concise way, use a pen to measure the common terminal of the corresponding PLC output point. If the pen does not light up, it may correspond to the shortcomings of the power supply such as the fuse of the safety wire. The electric pen is bright, declaring that the power supply is good, and the corresponding solenoid valve, contactor, and wire have shortcomings. After eliminating the shortcomings of solenoid valves, contactors, wires, etc., it is still ambiguous, so operate a multimeter pen, connect the corresponding output common terminal at one end, and contact the corresponding PLC output point at the other end, at this time, the solenoid valve and so on still do not act, declaring the shortcomings of the output line. If the solenoid valve is activated at this time, then the problem is at the PLC output point. Because the electric pen sometimes falsely declares, another method can be used to analyze, with a multimeter voltage level PLC output point and the voltage of the common end, the voltage is zero or close to zero, the PLC output point is declared in general, and the shortcomings are in the periphery. If the voltage is high, it means that the contact resistance of this contact is too large and has been damaged. In addition, when the light is not on, but the corresponding solenoid valve, contactor and other actions, this output point may be overloaded or short-burned. At this time, the external wiring of this output point should be removed, and then the resistance of the output point and the common end should be measured with the resistance of the multimeter resistor, if the resistance is small, it is declared that this contact is broken, if the resistance is infinite, it is declared that this contact is good, and the corresponding output light should be broken.
4. French logic speculation
At this moment, there are many varieties of PLC often used in the industry, for the low-end PLC, the ladder instructions are similar, for the high-end machine, such as S7-300, many French expressions are written in words. The applicable ladder diagram must have Chinese symbol annotations, otherwise it is very hard to read, if you can experience the equipment process or operation process before looking at the ladder diagram, it seems easier than force. If the electrical defect analysis is carried out, the reverse check method or the reverse deduction method is generally used, that is, according to the input and output correspondence table, the output relay of the corresponding PLC is found from the defect point, and the logical connection of its action is met by the reverse check at the beginning. Experience confesses, if a problem is found, the shortcomings can be eliminated, because there are not many shortcomings of two or more at the same time in the equipment.
5. Identification of the shortcomings of the PLC itself
Generally speaking, PLC is an extremely reliable device, and the defect rate is very low, but due to external reasons, it can also lead to PLC damage.
|
More on that
|
Precautions when connecting the servo and the PLC
(1) The PLC itself should be grounded according to the specified wiring specifications and grounding conditions, and attention should be paid to prevent the use of common grounding wires with Xinjie servo, and the two should be separated as much as possible when grounding.
(2) When the power supply condition ...
|
|
The cause of abnormal noise of PLC input and output module - Xinjie
Input and output module, if it is the kind of relay output, it is normal to have a little movement, because the relay is a mechanical equipment, there will be a little noise during the action, but the average person can not hear it, if it is obvious, it is estimated that the relay is broken, such as a short circuit between the turns of the coil, please pay attention to: Rongji point ...
|
|
The steps of the system put into operation after PLC overhaul - Xinjie
After overhauling and confirming that all connections of the system are correct, power on the relevant modules until the card indicator shows normal.
The initiation process of the system after the scheduled repair is as follows:
(1) Power supply. Turn on the power supply equipment (including the UPS...)
|
|
The risk cost of using the inverter - Xinjie
When we select the right inverter brand, we need to recognize whether it can help enterprises better manage the risks and costs caused by potential safety, security and downtime accidents.
Safety: Reverse arc drives assist users in meeting stringent reverse arc specifications. These inverters (Variabl ...
|
|
PLC input and output circuit debugging - Xinjie
1. Analog input (AI) loop debugging. Carefully check the address assignment of the I0 module; Check whether the loop power supply method (internal or external) is consistent with the field instrument; Use a signal generator to check the participating signals of each channel at the field end, generally taking three points of 0, 50% or 100%. ...
|
|
Introduction to Xinjie touch screen TP
1. Introduction
TP Contact Industrial Graphic Displayer (referred to as contact screen) is a human-machine interface (known as HMI or MMI in foreign countries) that connects humans and machines (mainly PLC), which is known as the face of PLC. It is a generation ...
|
|
Advantages of Xinjie touch screen and PLC wireless measurement and control network solution
1. Save the transformation cycle, no need for large-scale construction: eliminate the trouble of wiring maintenance, and easily complete the transformation within one day and meet the requirements of communication stability.
2. The device is simple, no programming is required: the wireless communication terminal only needs to ...
|
|
Small PLC Market Analysis - Xinjie
PLC programmable logic manipulators are the core part of industrial control. According to the number of I/O points of PLC, PLC can be divided into three categories: small PLC, medium and large. It is a digitally operated electronic device designed for industrial production. It uses a programmable memory to store programs that execute user-facing ...
|
|
Xinjie developed professional solutions for sealing lines
Introduction to the glass sealing industry
As a relatively old industry, the vitality of the glass industry has further burst out in the modern society, due to the social development and the improvement of people's aesthetics, the demand for glass in all walks of life is also increasing, which is also more abundant.
|
|
Advantages and opportunities of domestic PLC - Xinjie
At present, in the domestic PLC market, there are many kinds, but there are not many domestic PLC manufacturers with real strength, most of the domestic PLC is not an individual who does not have the qualification of a legal person, or a single-chip microcomputer enthusiast, from the domestic PLC factory to buy the underlying programming code or buy a domestic PLC chip (the domestic P that burns the underlying code...
|
|
Xinjie launched a professional solution for tapping machines
Tapping machine is a kind of machine tool that uses taps to process internal threads, and it is the most widely used internal thread processing machine tool. The tapping machine avoids the limitations of lathes, drilling machines or manual tapping, and saves time, labor, is not easy to rot teeth, and taps are not easy to break.
|
|
The range of use of universal frequency converters
A universal inverter is an electronic device used to control the speed of an electric motor, which can change the speed of the motor as needed, and then achieve higher production efficiency and power savings. The universal inverter has a wide range of application scales and can be used in various types of motors, including communication motors, direct motors, ...
|
|
Attention to the solution of heat dissipation in the application of inverter - Xinjie
Assuming that the inverter has a long service life, heat dissipation must be carefully considered. Because the equipment failure rate of the inverter increases exponentially with the increase of temperature, the service life decreases. If the operating temperature rises by 10 degrees, the service life of the inverter will decrease.
...
|
|
Learn PLC programming skills - Xinjie PLC
1. When the PLC and the host computer (or touch screen) form a monitoring system, there are many times on the screen that there are "manual", "active" and other control modes (generally more than one). In the program, you can use the "MOV" command. For example, when selecting "manual", the constant 1MOV will be ...
|
|
Xinjie inverter control motor method
The Variable-Frequency Drive (VFD) controls the speed and operation of the motor by adjusting the frequency and amplitude of the output voltage. Specifically, the VFD controls the speed of the motor mainly through the following steps:
Collecting Input Signals: VFD First ...
|
|
The way the PLC controller works - Xinjie
Although many relays, timers and counters are often used in the ladder diagram programs used by PLCs, PLC does not have these hardware physically, but uses memory and program programming methods to do logic control and editing, and connects external mechanical devices to make physical devices through output components.
|
|
Introduction to PLC debugging steps - Xinjie
Input and output loop debugging
1. Analog input (AI) loop debugging. Carefully check the address assignment of the I0 module; Check whether the loop power supply mode (internal power supply or external power supply) is consistent with the field instrument; Use a signal generator to add a signal to each channel at the field end, generally taking 0, 5 ...
|
|
Inverter daily inspection items - Xinjie
(1) Whether there is an abnormal change in the sound during the operation of the motor, including whether there is vibration during the operation of the motor.
(2) Whether the installation environment of the inverter has changed. Whether the ambient temperature is normal, the operating temperature of the inverter is generally required to be in the range of -10 °C - +40 °C, and it is better to take about 25 °C.
|
|
Fault distribution of PLC control system - Xinjie
In order to shorten the early problem period, further extend the random problem period, and postpone the arrival of the wear and tear problem period, we will generally choose the method to take a certain approach at the beginning of the system planning.
|
|
Xinjie MS6 series high-performance servo motor is pleased to mention the 2020 "Automation Innovation Award - Motion Control Category"
On March 19, 2021, the "Made in China Digital Service Summit 2021 CAIMRS and Annual Selection and Award Ceremony" held by China's industrial control network was broadcast live on the cloud of the "Industrial Control Network Digital Conference Hall". At the meeting, Pan Yingzhang, President of Gongkong®, officially released China's automation and digital ...
|
|
Contact
working hours
