Tag Archives: plc

Type of PLC cable and name of various connectors

PLC communication, commonly used serial communication, Ethernet communication, fieldbus communication.

In serial communication, it is divided into D port and USB port. The D port is a nine-pin type, the needle is called a male port, and the mouth is called a female port. There are three protocols: RS232, RS422 and RS485. No communication protocol, the link method is not the same, so I won’t elaborate. Like the needle port of the computer, it is RS232, the round port of Mitsubishi PLC, RS422, Siemens PLC, RS485. Serial access, typically a point-to-point link, such as a PLC and one or more screens, does not allow multiple PLCs and multiple screens.
The communication protocol of the USB port is the same as that of the D port, but the D port can be soldered by itself, but the USB can only be purchased, and different manufacturers cannot be compatible.

The Ethernet communication port is the computer network port we have seen. It can be used with the network cable to distinguish the straight-through line and the cross-line. Ethernet communication, fast transmission speed, long distance, can be extended to fiber optic links, the distance is up to several kilometers, generally used for monitoring with the host computer.

There are many fieldbus categories. Now there are a total of 9 types in the entire electrical industry. The common bits are MOD and PROFIBUS. The protocols used are all confidential. Although the interfaces are all D ports (same as serial ports), the communication method is chosen. It has specificity and is mainly used to link multiple controllers in the field, such as multiple PLCs and multiple screens, allowing multiple master stations and slave stations.

How to collect analog input in Delta plc

Delta plc analog input

In addition to the host, you must also have an delta plc analog AD module. According to the manual, make the corresponding settings for the module (TO command). Use the FROM command to read the digital signal after analog-to-digital conversion of the AD module

Example: Input 0-20MA module conversion number is -2000 to +2000 Module model is 06XA-EH The following is the setting of 4 analog inputs.

LD M1002

TO K0 K1 HF000 K1

TO K0 K18 K0 K4

TO K0 K24 K1000 K4


The main reason is that the program written by PLC has made mistakes, some of which may be logical errors, or may be input errors. You have to check it out.
Programmable logic controller (programmable logic controller), which uses a class of programmable memory used in its internal storage program, executes user oriented instructions such as logic operation, sequence control, timing, counting and arithmetic operation, and controls various types of machinery or production process by digital or analog input / output.

How to count the MITSUBISHI PLC counter

Parallel the Y0 and C0 at the output end. When the Y0 triggers the output once, the C0 will count once.
The counter must have a reset instruction. Technology completion triggers RST C1 reset
If you want to display the count times on the touchscreen, use the MOV command to send the C1 count to register D.
The display component of the touchscreen should select the display address, and the address is the D register you sent. For example, D1 D2 and so on. The display screen can display the data of the register.
The CD port of touch screen is the power supply interface, usually 24V DC. The communication port is the COM port. And that is to download the USB port. There is no technical port. Counting, timing and so on in PLC, all kinds of data are communicated through COM port.

PLC positive and negative ladder

Mitsubishi PLC
X000 is the forward button, X001 is the reverse button, X002 is the stop button; Y000, Y001 for the PLC output, then two AC contactor KM1, KM2 to control the motor reversing

Siemens PLC program

I0.0 is the forward rotation button, I0.1 is the reverse rotation button, I0.2 is the stop button; Q0.0, Q0.1 is the PLC output connected with two AC contactor KM1, KM2 to control the positive and negative rotation of the motor

PLC control motor forward and reverse

X0 Forward button, X1 Reverse button, X2 Stop button, X3 Limit 1, X4 Limit 2, Y0 Forward rotation output, Y1 Reverse rotation output

CN1 wiring diagram of MITSUBISHI MR-J3 servo amplifier

2. servo motor: HF-SP502
3. drive: MR-J3-500A

This is my first use of MITSUBISHI’s system, and the first time to learn and apply the servo positioning system.

What is PLC?

PLC = Programmable, Logic, Controller, programmable logic controller, an electronic system for digital operation, designed for use in industrial environments. It uses a programmable memory, used in its internal storage procedures to perform the logic operation, sequence control, timing, counting and arithmetic operations such as user oriented instructions, and through digital or analog input / output control various types of machinery or production processes. It’s the core part of industrial control.
At present, PLC has been widely applied in iron and steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection, water treatment and cultural entertainment industries, using general can be summed up as follows.

1 、 logic control of switch quantity
This is the PLC the most basic and most widely used, it is replacing the traditional relay circuit, logic control, sequence control, which can be used for the control of a single device, can also be used for machine control and automation line. Such as injection molding

2 analog control
In the process of industrial production, there are many continuous changes, such as temperature, pressure, flow rate, liquid level and velocity, etc.. In order for the programmable controller to process analog quantities, the A/D conversion and D/A conversion between analog (Analog) and digital (Digital) quantities must be implemented. PLC manufactures both A/D and D/A conversion modules that allow programmable controllers to be used for analog control.

3, exercise control
PLC can be used for the control of circular motion or linear motion. From the configuration of the control mechanism, the former is used directly for the switch I/O module, the position sensor and the actuator. Now, the special motion control module is used. Such as the stepper motor or servo motor single axis or multi axis position control module. Almost all of the major PLC manufacturers in the world have motion control functions, which are widely used in various machines, machine tools, robots, elevators and so on.

4, process control
Process control refers to the closed-loop control of analog quantities such as temperature, pressure and flow. As an industrial control computer, PLC can work out a wide variety of control algorithms to complete closed-loop control. PID regulation is a widely used adjustment method in general closed loop control systems. Large and medium-sized PLC have PID modules, and many small PLC also have this function module. PID processing is typically running PID subroutines that are specific. Process control has a wide range of applications in metallurgy, chemical, heat treatment, boiler control and other occasions.

5, data processing
Modern PLC has the functions of mathematical operation (including matrix operation, function calculation and logic operation), data transfer, data conversion, sorting, table look-up, bit operation, etc. it can complete data collection, analysis and processing. These data can be compared with reference values stored in memory, complete a certain control operation, or can be transferred to other intelligent devices by communication function, or printed and recorded. Data processing is generally used in large-scale control systems, such as unmanned flexible manufacturing systems, and can also be used in process control systems, such as paper, metallurgy, and food industry.

6, communications and networking
PLC communication includes communication between PLC and communication between PLC and other intelligent devices. With the development of computer control, factory automation network is developing very fast, and all PLC vendors attach great importance to the communication function of PLC, and have launched their own network systems. The newly produced PLC have communication interface, and communication is very convenient.

In short, PLC is mainly used to achieve industrial automation control procedures, but now because of the development of the hardware and software function more and more powerful, and increasingly low cost, its application is not limited to industrial countries in recent years, in addition, vigorously promote industrial restructuring, so industrial automation is becoming more and more popular, so as to achieve the backbone PLC industrial automation control, PLC forward good.

6RA70 equipment, in the direction of the times police F030!

A company 6RA70 equipment, in the direction of the times police F030!
Problem supplement:
My equipment is reversible rolling mill, each time the alarm F030 is the time to change, and sometimes just change the alarm, and sometimes to go for a while and then alarm, alarm reset after the normal work!

Best answer

Fault F030:
Detection of current loop optimization, the need to re optimize the current loop. Activate the “trace” function by using the fault to find the cause of the fault.
If the fault value is 1 or 2, if necessary, can be set U580 = 4, a detailed description of the U580 see instructions or document: http://support.automation.siemens.com/WW/view/en/19868341 value is 3 (such as fault current greater than r072.02 250%) may be due to the four quadrant braking device in voltage sag. Check motor brush commutation without ring fire, you can refer to the maintenance of the old motor. Note: fault F030 can only use U580 = 0 shield (can not use P820 shield).

Damage cause of s7300 analog input module

S7300 analog input module (331-7KB02-0AB0 6ES7) 3 years of bad 2, the input signal 4-20mA, consult the module is easy to damage the reason?

Best answer
Reference: analog quantity module damage
Http://www.ad.siemens.com.cn/service/answer/solution.aspx? Q_ID=63278&cid=1029?