Tag Archives: Learn PLC programming

what basic knowledge to learn plc?

Need to have an electrician, assemble secondary lines, and understand the basics of various relays.

Learning the PLC can be done as follows:

1. Buy this book about PLC, learn about electrician knowledge, understand the electrical appliances, and go to control and understand various actuators.

2, is to understand the working mode of PLC, find a PLC, according to the example on the book, consider a small project, to achieve a function.

3, practice the true knowledge, understand the corresponding process, do a PLC project independently, the project is completed, the PLC will also master the Siemens 200 series of small PLC is very suitable for novice learning, easier to get started.

What is the foundation for learning plc programming?

The conditions for self-learning PLCs should be as follows:
1, you have to learn programming software PLC (such as Siemens, Delta, Omron, etc.), each brand of PLC its programming software is slightly different, so what software to prepare what PLC.
2, it is best to reserve an HMI (Human Machine Interface), because PLC often needs to do some configuration control, it is really not good to achieve this, of course, now a lot of two in one, you can prepare a two-in-one device it is good.
3, a set of PLC programming software and HMI programming software
4. Relevant circuit design knowledge.

how to connect plc to hmi

How to connect plc to hmi

I want to modify the timer’s time with the touch screen.
1. Read out the program in FX2N PLC with software, find the constant value K of the timer used to set the time, modify the constant K to D directly when programming, D should choose power off to keep the data register, the range is between D200-D511, and other fixed, and then write it into PLC.
2. Choose the type of touch screen, it is recommended to choose the Vinylon MT6056iv touch screen, programming with software, a numeric setting button, the button corresponding to the PLC data register D, when the finger touches the button, there will be numeric input keyboard, at this time, you can modify the timer time.
In the market, any touch screen and PLC usually do not communicate well. There are four problems to be confirmed.
1, is the PLC parameter consistent with that in the project?
2, whether the communication line is connected to the pin according to the wiring diagram.
3, the project set up the COM port on the screen when the correct 4. Parameters and line confirmation OK, in the case of PLC program or PLC address problem.

Methods: (first judge parameters:)

1. Use the programming software of PLC to connect with the PLC test to see what the parameters of PLC are and whether the parameters set in the project are consistent with the test results.
2. On-line simulation: with our configuration software, using the plc’s own communication cable and computer connection, on-line simulation to see if the project is communicating. You can use a numeric input unit or switch to operate on it, to see if the simulator is turned off and then on-line simulation before the operation is still, whether direct prompt NC. (NC and previous operations have not been written down.
(test line): use the multimeter to define the test wiring according to the pin of the wiring diagram.
A: parameters of touch screen. Check the parameter settings of the touch screen.
There are several parameters that need special attention.
1: Communication Port Settings – – – – – – – – – – Make sure that the PLC connects to the touch screen COM1 port or COM2 port
2: Type of equipment – – – – – – – – – – – – – – – – – – – – – – This is the most important, if the agreement is not chosen correctly, the others do not have to say
3: Connection mode – ————– PLC and touch screen connection, confirm good news RS485, or RS232C
4: Interface parameters and PLC station number – ———– must be consistent with the PLC settings.
B: if the parameter confirmation is set up, then check the wiring problem. Confirm the correctness of RS485 and RS232C, and touch screen is different from all kinds of PLC wiring. This can refer to dimensional control (PLC and touch screen communication line help files).
This is the basic method of normal troubleshooting communication problems.
Next we will teach you how to bypass the problem of touch screen — online simulation.
When communication fails, some customers guess that it may be a touch screen problem or an interface problem.
Online simulation is to bypass the touch screen and connect directly to the computer with PLC.

Specific measures:

1:PLC is connected to the computer through RS232. Some PLC have RS232 interface, some do not, and none can connect to the computer through the adapter.
2: build a simple project. Put two components, a numeric value, a numeric input. Address to set the address in PLC.
3: the setting of engineering parameters must be the same as that in PLC.
4: click on the online simulation function, so you can clearly check whether PLC can communicate with PC. If you can communicate, you can exclude the problems of PLC, and the problem of parameter setting.

MPS, MPP, MRD in PLC

1, MPS (into the stack instruction): The result of the operation into the first segment of the stack memory, while the previously sent data to move to the next section of the stack.

2, MRD (read stack instruction): the first paragraph of the stack memory data (last into the stack of data) read and the data continues to be stored in the first paragraph of the stack, the data in the stack does not move.

3, MPP (out of the stack instruction): The stack memory of the first piece of data (the last stack of data) read and the data from the stack disappeared, while the other data in the stack in turn up.

What‘s’ mean of Mitsubishi PLC directive MOVP HOFF k2y0

The MOVP represents the pulse transmission instruction,The h in Hoff represents the 16 binary, which represents the hexadecimal FF,K2y0 represents Y7y6y5y4y3y2y1y0, which is the two sets of 4 digits starting with Y0, and if K1y0 represents Y3y2y1y0,This directive indicates that the 16-in-system FF is delivered to the results of the y7y6y5y4y3y2y1y0 execution y7=1, y6=1, Y5=1, Y4=1, Y3=1, Y2=1, Y1=1, Y0=1.

What is the meaning of MOVP in PLC?

The MOV in PLC is the transmission instruction, for example [mov K15 D100] means to transfer the decimal constant K15 to register D100.

MOV is continuous execution, that is, each scan cycle is transmitted once.

Example:

LD X0

MOV K100 D10

When X0 is ON, K100 is transmitted to D10 and automatically converted to binary number.

MOVP is a pulse execution, that is, the instruction is activated once, and a transfer is performed.

Example:
MOVP K2M200 D40

The value of m200–m207 in decimal form is assigned to D40
MOVP K11 D0:

A transfer process is performed when conditions are available.

(pass constant 11 to D0 data register). It is usually performed only when there is a rising edge.

MOVP H1A2 U0/G0

It is to transmit H1A1 to module 0, buffer 0.

Application of PLC in capsule curing machine

In the tire curing process, the capsule as the necessary parts of the tire processing, there is a high performance requirements. It needs to undergo repeated expansion and contraction, stretching and other deformation, but also experienced a sharp rise and cooling. Capsule curing is one of the key processes to obtain high quality performance, and it is also one of the most important processes in capsule production. The process is to first make the rubber material through the appropriate processing of semi-finished products, and then through the chemical effect, the semi-finished products made capsule shape, to meet the performance of the use of tire processing.

Capsule curing process includes mold, mold, mold, mold, and so on. Capsule vulcanizing machine controlled by the movements of the core rod, the core rod and the main oil cylinder, combined into the core mold cavity the formation of capsule vulcanizing pressure required, at the same time through the access control to control the steam curing temperature required. Most capsule curing machine adopts hydraulic system. The hydraulic pressure station controls the upper die, the lower die and the main oil cylinder by the oil pipeline.

With HOLLiAS LM series PLC analog acquisition of high precision, good ductility, network characteristics, and put forward a set of small PLC based on Hollysys capsule vulcanizing machine control system solutions. This scheme overcomes the traditional relay of capsule in curing pressure, temperature and time of the three elements of the control is not precise, high failure rate shortcomings, has a certain reference value for the application of PLC in industry capsule vulcanizing machine.

According to the input and output point requirements, select the 40 point CPU module LM3109 and 4 channel analog input module LM3310. The switching input of the control system mainly includes the operation mode switching button, the setting button and the action button. The analog input of the system includes a temperature transmitter signal input and a pressure transmitter signal input. The output of the system includes a motor, an electromagnetic valve, an indicator light, etc.. Touch screen for input parameters, while monitoring the current state of operation and time. Computer as a remote monitoring equipment, can be connected with the PLC, used to save and monitor the running state of the capsule curing machine. The control system of the capsule curing machine mainly realizes the accurate control of pressure, temperature and time in each stage of curing, the fault detection and alarm, the parameter record and communication.

The HOLLiAS LM series PLC designed a capsule vulcanizing machine temperature and pressure control system has high control precision, network interface and features rich, achieve a capsule vulcanizing machine, automation control and network management, greatly improving the capsule production efficiency and product quality, to meet the high quality, high efficiency, low failure rate etc..

PLC how to learn, how to learn for beginners PLC?

Develop a good interest

Since all of the PLC programming is not interested, then how can learn it. So it can be programmed as an interesting intellectual game, this will cause you to have enough patience and perseverance to complete the program.

PLC learning to focus on practice, there is no practice is absolutely not good. This is also the most critical learning PLC.


So when programming need as practice object PLC and related hardware equipment, it can also program intuitive response with the actual equipment action in the detection procedure, so that the error action of equipment can easily find the point of failure, or no control object, fault point to analysis, to program it is difficult to judge the correctness of.

Develop the good habit of programming

In the preparation of a slightly complex project, we need to analyze the process of the project —- that is, drawing the flow chart

In the preparation of procedures, the use of the intermediate relay to have the order and rules, otherwise the program will be very disordered, and in the future of the program changes and their troubles.

At the same time, in the preparation process, the every step, the role of each signal and the intention to mark, so you know your own programming every step of the intention, and in the process of looking back at a glance.

Often communicate with peers

PLC application and its wide range, its control function is also changing, and peer exchanges can promote the development of knowledge, and in the exchange process can reflect their own shortcomings.

At the same time when you encounter problems, the exchange is particularly important, they do not understand the technology, there may be a little hint, it will become very simple to solve.

Finally, on the network at present there are a lot of PLC learning materials and related technology, can understand the relevant technology through the network, so you can have to understand the various techniques for later use when targeted learning.

Art lantern shape PLC Ladder programming and wiring experiment

This article describes an artistic lantern shape PLC ladder programming and wiring experiment described, as follows:

1. Project the necessary equipment, tools, materials

PLC: FX2N-32MR

2, the training content:
1, project description
The shape of an art lantern demonstration board as shown in Figure 6, A, B, C, D, E, F, G, H for the eight lights, a ring distribution. The control requirements are as follows:
Will start switch K1 close, eight lighting light at the same time, namely abcdefgh light at the same time a second, then eight lighting according to counter clockwise rotate the light seconds, a bright 1s > b 1s > C bright bright 1s > d 1s > e bright bright 1s > f light 1 second g > bright 1s > h light 1 second; next eight lighting and light at the same time 1: abcdefgh and light 1 second; and eight lighting according to clockwise rotate the light 1 second, namely h bright 1 g > light 1 second > f light 1 second, e light in the 1s > d 1s > C bright bright 1s > B bright second, a bright light for 1 second. Then repeat the execution in this order. Press the stop switch K1, all the lights off.

2.2 PLC wiring diagram
According to figure 7 to meet the good line. Note that the COM1 and COM2 are connected, as the same as the rated voltage of the indicator light. Input and then start switch and stop switch.
2.3 program design
Figure 8, PLC operation, the program 9 to 19 step, M11 conduction, due to the step program of 50 to 120, M11 dynamic contact closure, respectively control the Y0 Y7 conduction and lantern abcdefgh lit up at the same time, the due t0 delay 1 seconds, so the abcdefgh lit up at the same time 1 seconds. To 1 seconds, the program step 40 t0 dynamic contact closure, shift instruction execution, implementation turns light, namely abcdefgh turns light, because a second clock t0 closed once, so abcdefgh turns light interval for a second. Step 20 to 29, when the M20 pass, the M101 set, the M101 moving contact with MI2 ~ M19 moving contact with the contact, respectively, turns lit H ~ A, that is, G, F, H, E, D, C, B, A turns lit every second. Step 30 to 39, when the M20 pass, the M101 reset, M101 dynamic break contacts with MI2 ~ M19 dynamic contact contact, respectively, in series lit A ~ H, that is, A, B, C, D, E, F, H, G turns lit every second. At any time will stop the switch K2 closed, in the 114th step, the interval reset command so that M19 ~ M12 all reset, all the lights are not bright.
2.4 run and debug program
(1) the ladder diagram program is entered into the computer, check the power supply is correct.
(2) to debug the program.
A. connected to the PLC power supply, the PLC will be RUN state, the K1 closed, observation of A, B, C, D, E, F, G, H, the light show.
K2 will be closed, A, B, B., C, D, E, F,, G, H, the light show.
(3) debug running record.

Application and characteristics of PLC in control system

What is the meaning of the programmable controller:

Acronym PLC programmable controller or PC, is evolved from the early relay logic control system, which constantly absorbing function of the microcomputer technology to growing gradually for complex control tasks.

Since 1836 relay came, people began to use it skillfully wire connected with the switching device, constitute use different logic control or sequential control. So far, the PLC Ladder programming language can also see the shadow of these wires. Until the late 1960s and early 1970s, the advent of programmable controllers, with the rapid development of microelectronics technology, computer technology and data communications technology, as well as the emergence of the microprocessor, PLC products towards small and ultra-small aspects of a leap , and finally to the early PLC from the initial logic control, sequential control, it has developed into a modern PLC logic, timing, counting, memory and arithmetic operations, data processing, communications and networking functions such as PID loop controller.

PLC viable reason is that it is more suitable for industrial field and the requirements of the market: high reliability and easy ability against various disturbances, programming installation, low price and long life. Than the microcontroller, its input and output closer to the field devices, without adding too many intermediate member or need more interfaces, which saves users time and money. PLC lower end (input) for the relay, transistor and thyristor control means and the upper end is generally user-oriented microcomputer. When people use it, you can not carry out specialized training in computers, programmable controllers can be operated and programmed. Used to perform a variety of different complexity industrial control tasks.
First, the main function of the programmable controller

PLC application is very broad, very rapid development of industrial automation equipment, factory automation (FA) and computer integrated manufacturing system (CIMS) in the important role. Today’s PLC function, far not only replace the traditional relay logic.
PLC system is generally constituted by the following basic functions: a variety of control functions. Data collection, storage and processing capabilities. Communications networking. Input / output interface conditioning. HMI function.

Programming, debugging features:
1, the control function logic control: PLC has the AND, OR, NOT, XOR logical operations and other functions, and triggers can replace relay switch control.
Time control: It provides users with a number of electronic timer, users can set their own: on-delay, off delay and timing pulses and other means.
Count Control: pulse control can add, subtract counting mode, you can connect encoder for position detection.
Sequence control: the first after the procedure is completed, it is transferred to the next process, so that a PLC can use as a multi-step controller.
Data collection, storage and processing math functions:
Basic arithmetic: add, subtract, multiply and divide.
Extended arithmetic: square roots, trigonometric functions and floating point arithmetic.
Compare: greater than, less than and equal to.
Data processing: Select, organize, normalize, move, and first in first out.
Analog data processing: PID, integral and filtering.
2, the input / output interface conditioning functions having A / D, D / A conversion, complete analogue control and regulation through the I / O modules. Median and accuracy can be selected according to user requirements.
3. Has the temperature measurement interface, direct connection to a variety of resistance or galvanic.
4, communications, networking have adopted most modern PLC communication, network technology, RS232 or RS485 interface for remote I / O control, more than one PLC to one another networking, communications, external devices and one or more between the programmable controller signal processing unit, program memory and data exchange, such as the transfer of the program, data file transfer, monitoring and diagnostics.

The communication interface or communication processor hardware interface standard or proprietary communication protocols and data transfer process is completed. Such as the Siemens S7-200 Profibus fieldbus port, the communication speed may reach 12Mbps.
When the system is constituted by a computer with multiple PLC constitute centralized management, decentralized control of distributed control network to complete large-scale complex control. Commonly referred to as SCADA systems, on-site and remote terminal PLC terminal can also be used for live machine. 5, man-machine interface function provides the operator to monitor machine / process work necessary information. Allows the operator and PC systems interacting with their applications, in order to make decisions and adjustments.

Means to achieve human-machine interface functions: from the grassroots operator screen text display, the stand-alone CRT display and keyboard operation and decentralized communication processor, a dedicated processor, a personal computer, industrial computers, and centralized operation and monitoring system. Use 6 different complexity, programming, debugging and other hand-held, portable and desktop programmer, and operator workstation screen, programming, debugging, monitoring, testing and records, and printing out the program files.

Second, the main features of the programmable controller
1, high reliability PLC’s MTBF is generally 40000 ~ 50000h above, Siemens, ABB, Panasonic and other micro PLC of up to 100,000 h or more, and have a sound self-diagnostic function to determine the fault quickly and easy to maintain. 2, the modular combination of flexible programmable controller series products, the module structure commonly used to accomplish different tasks combinations. I / O from 8 to 8192 points, there are a variety of models, a variety of function modules can be flexibly combined, structure is also diverse. 3, powerful PLC application of microelectronics and micro-computer, simply type have logic, timing, counting sequence control. The basic types plus analog I / O, the basic arithmetic operations, communications and so on. In addition to the basic types of complex types of functions, but also has a scalable computing power, multi-level terminal mechanism, intelligent I / O, PID regulation, process monitoring, network communications, remote I / O, multiple processors and high-speed data processing capability . 4, convenient programming PLC control suitable for industrial ladder, function block diagram, instruction list and sequential function chart (SFC) programming, without much knowledge of computer programming. The new programming workstation with a comprehensive software toolkit, and on any PC-compatible programming. 5, to adapt to the technical conditions of the industrial environment PLC can work under the general high temperature, vibration, shock and dust and other harsh environment, can work reliably under strong electromagnetic interference environment. This is the market value of existence PLC products. 6, installation and maintenance is simple compared with the computer system, PLC installation does not require special rooms and rigorous screening. When you use as long as connectivity to various devices is correct, the system can work with operating and fault indication means on each module, easy to find fault, most of the modules can be hot plug, the module can be replaced, so that users can in the shortest isolated time fault, and exclude, to maximize compression downtime, rapid recovery of production. Then repair fault module, which is particularly suitable for large-scale production situations.
Some PLC housing is made of an alloy that can operate under poor working conditions, with the simple structure, with a heat sink above, at high temperatures, unlike the housing plastic deformation, as also anti-radio frequency (RF high frequency) electromagnetic interference, fire and so on. 7, fast with microprocessor applications, so that the speed of the PLC faster, make it more in line with the processing speed of complex control tasks, the difference between it and the microcomputer is not very obvious. 8, the low weight of the total price of the PLC, volume, power, and hardware prices have been reduced, although the proportion of total software price has increased, but the manufacturers to compete also a corresponding reduction in prices. In addition, the use of PLC can also greatly shorten the design, programming and commissioning period, bringing the total price is further reduced.
PLC systems and industrial computer bus and DCS system of mutual penetration, mutual learn, compete and development. Promoting the progress of industry.
PLC fieldbus products face development, innovation will once again meet the higher needs of the industrial and civilian control. Third, communications and networking PLC communication between the PLC, including PLC, the communication between PLC and host computer and PLC and other intelligent devices. PLC system can be a general purpose computer or via the communication processing unit, a communication adapter connected directly to form a network to achieve the exchange of information and may constitute centralized management, decentralized control of distributed control system to meet factory automation (FA) systems development needs of each PLC or remote I / O module according to the functions of each place at the production site decentralized control, then using a distributed network system connected to form a network of centralized management.
Siemens company SIMATICNET example, in the Totally Integrated Automation (TIA) system concept proposed in its core content which includes integration and integrated communication configuration and programming of integrated data management. Communication networks are important, the key components of this system to provide inter-network components and improve the industrial communication.

SIMATICNET contains three main levels:
International standard AS-I network sensors and actuators communication scan time 5ms, the transmission medium is twisted pair, unshielded line length of 300m, a maximum of 31 slaves.
PROFIBUS industrial field bus, the international standard for the workshop and field level, the maximum transmission rate of 12m / s, the transmission medium is shielded two-wire cable (up to 9.6km) or cable (up to 90km), can connect up to 127 from station.
International standard industrial Ethernet networking for regional and unit, the network size of up to 1024 stations 1.5km (electrical network) or 200km (optical network).

In this network system, it is particularly worth mentioning is the PROFIBUS fieldbus, PROFIBUS field bus is one of the most successful, have been widely used. It is not dependent on the manufacturer, open field bus, a wide range of automation devices can exchange information through the same interface. A large number of manufacturers to provide high-quality products PROFIBUS, the user can freely choose the most suitable product. PROFIBUS has become the national standard DIN19245 German and European standards prEN50170, and in the world has the largest number of users. Four, PLC and industrial control computer (IPC) to compare and distributed control systems (DCS) 1, the origin of their computer technology to meet the rapid development of large amounts of data processing equipment required. Hardware structure, high degree of standardization of the bus, compatibility, rich software resources, especially the support of real-time operating system, so the requirements of fast, real-time control and computation model complex workload industrial objects advantage.

Distributed system development from the industrial automation instrumentation control systems to industrial control computer as the center of the distribution system, so its processing in the analog loop adjustment has certain advantages, mainly used in the initial stage continuous process control, focusing loop control functions.
PLC is evolved by the relay logic system, mainly used in discrete manufacturing, process control, instead of the initial main relay control system, switch the order of emphasis on control.

With the development of microelectronics technology, large scale integrated circuit technology, computer technology and communication technology, etc., PLC happened leap in technology and functionality. On the basis of the initial logic operation, an increase of numerical computation, loop adjustment and other functions, and adds analog PID control function modules; computing speed, CPU capacity to catch up with industrial control computer; enhance communications capabilities developed more species and local bus network (LAN), and thus can also be configured as a distributed system. Especially personal computer can also be absorbed into the PLC system.

PLC ladder programming rules

Although the ladder and relay circuit is similar in structure, elements, symbols and logic control functions and other aspects of phase, but they have many differences, the ladder program has its own rules.

1) Each logical line is always to the left from the bus, and then the contact is connected, the final termination of the coil or the right bus (right bus can not draw). Note: The bus between the left and the coil must be contacts between the coil and the right bus but you can not have any contact.

2) The ladder can contact any series or in parallel, but only in parallel to the relay coil and not in series.

3) the use of contacts unlimited number of times.

4) In general, the same coil can appear only once in the ladder. If in the program, the same coil is used twice or more times, known as “dual-coil output.” For the “dual-coil output”, some PLC treats it as a syntax error, and definitely not; some will be in front of the PLC output as invalid, only the last valid output; and some PLC, containing a jump or step ladder instruction allowed dual coil output.

5) For non-programmable ladder must be equivalent transformation into programmable ladder.
6) when there are several series circuit in parallel, the circuit with many serial contacts should be on the top, as shown in Figure 5-2a. There are several in parallel circuit in series, the circuit should be parallel contacts on the left, as shown in Figure 5-2b. Such a program compiled concise, less statements.


In addition, the input of the relay contacts in the design of the ladder according to the best state of all the input device is normally open to design more appropriate, less error-prone. Is recommended as an input device open with a constant contact with the PLC input terminal, the signal can only be used if some normally closed input, press input device is normally open to design, and then the ladder corresponding input relay contacts point negated (normally open into a normally closed, normally open normally closed change).

PLC ladder programming principles and programming methods

(1) Input / output relay, internal auxiliary relays, timers, counters and other devices of the contact can be used repeatedly, without complex program structure to reduce the use of contacts. (2) Each line ladder left the bus started, the coil terminates at the right bus. Contacts are not on the right side of the coil, as shown below

(3) In addition to stepping procedure, any coils, timers, counters, and other advanced instruction can not be directly connected to the left bus bar.
(4) In the process, does not allow the same number twice coil output (dual coil output). The following ladder is not allowed.

(5) does not allow the bridge circuit.

(6)Shall be prepared by the sequential program from top to bottom, from left to right to prepare the way. To reduce the number of steps in the implementation of the program, the program should be to the left and right big small big small.

(7) as an input device with a normally open contact

(8) PLC programming experience commonly Design
In the traditional relay – contactor control diagram and typical PLC based control circuit, based on the experience accumulated translation, revised and improved to give final control procedures.

OYES PLC applied using a small wave soldering machine design

I. Overview
Usually large wave soldering machines, production lines, but some customers such as laboratories, schools, small factories need a small lead-free wave soldering machine. Certain electronic equipment factory developed this product, using the Austrian letter OYES series PLC and touch screen. The device requires three temperature control, a total of three PID, the Austrian letter OYES series PLC to achieve 8-channel PID, to meet the equipment requirements. Matched on the touch screen with a high price.
II. Process Description
Dual-wave soldering machine is first necessary to solder temperature, preheat temperature, preheat temperature compensation temperature value added to a total of three temperature settings. When the condition is satisfied, the machine can be produced. The PCB board placed on the track, press the start button, the transmission motor running, start the pump, spray flux, PCB board flux coating is completed, the delay pump stops. When the PCB board to the left after the preheat zone, the transport motor is stopped, parked in the PCB board preheat zone, preheat countdown, after the time to transfer the motor starts, the right to run the PCB, tin pump motor start HAL, PCB board after preheat temperature compensation zone into the HAL area, after HAL zone, tin pump stops when the PCB to the right, the motor stops transmission, cold start the motor. Such a complete cycle is over.
III. Hardware Configuration
Input: detection switch, the operating switch.
Switch detection are: the right point switch, left switch point.
Switch operation are: start switch, emergency stop switch.
Output point: heating solid state relay three regions, the transmission motors, two motors tin pump, exhaust motors, pump motors, motor cooling, the power to protect themselves point.
Analog inputs: three zones of temperature detection.
Motor transport and tin pump motor speed is required, using a frequency converter, the speed required communication settings.
Hardware Configuration:
Model Number Function
FBS-32MA 1 master controller, AC 220V input, relay output
FBS-16EYT 1 8x24V, transistor output module
FBS-6TC 1 4-channel thermocouple input module
Panelvisa PV057TST 1 Touchscreen HMI
IV. Programming
Including programming PLC program and touch screen program includes four major functions: Device parameters, manual debugging, production screen, alarm queries.
The following are some of the features: each movement device can be done manually debug screen is very useful when you start debugging and maintenance of equipment.
Device parameters can be set from the touch screen, including temperature, time, PID coefficients.
Alarm query, you can quickly find the cause of the malfunction.
Production data display screen is used in the production, buttons are placed in this picture, and user-friendly in this screen monitors three temperature zones, process instructions and operating in these images.
Transmission speed motor and pump motor tin set is set to the touch screen PLC, and then passed by the PLC via PORT1 each motor drive. Function uses the PLC MODBUS master station, very convenient.

Through the program determines the touch screen and plc communication failure method

The usual method is to use heartbeat, defined a bool, HMI fixed point set the frequency, PLC receives the point after ON signal is reset. If a period of time, for example, do not receive the points for the ON signal within 5s, it is considered Tongxu interrupted.plc to the memory clock of bytes transmitted to the screen, this screen script-byte value assigned to another address within a plc, plc judge then returned within two bytes of the scan cycle is the same, if the communication is interrupted as described .
 
For example, look at Figure, follow these steps:1, the establishment of a data block DB1 in the PLC, which provided two switch “PLC seconds switch” and “man-machine switch response”2, human variable connecting these two variables3, the display unit in the property “PLC seconds switch” variable —- event —- add value change “is negated bit” so that “in response to human-computer switch” variable with “PLC seconds switch” change change .4, PLC programming block, let ‘s PLC switch “reverse every 0.5 seconds, and then let TON delay instruction” man-machine switch response “no action within 1 second output man-machine communication failed because the man-machine communication after abnormal “man-machine switch response” will change no longer occurs.

PLC conduction delay timer instruction (TON)

When the limit switch 1 is set, the indicator 2 ON 180ms (timer clocked). When the accumulated value of the timer 1 (.ACC) reaches 180, 2 lights off, the indicator 3 is turned on, and remains on until the TON instruction is disabled. If you disconnect the timer is timing the limit switch 1, then turn off light 2.

Ladder Diagram


PLC program sequential logic design method

(1) overview
 
Sequential logic design method is suitable for the output signals of the status change of the PLC has some chronological situation, when in programming according to draw sequence diagram of the output signal, streamlining the state transitions and transition conditions, examine the output and input and internal contacts and the relationship, and make the appropriate reduction. In General, the sequential logic design method should be used with the experience, or will probably make the logical relationship is too complex.
 
(2) sequential logic design method of programming steps
 
1) according to the requirements, specific number of input/output signals.
 
2) clear the timing relationship between the input and output signals, draw sequence diagrams from the various input and output signals.
 
3) sequence diagram can be divided into several sections, find the demarcation point between the sectors, identify boundary point output signal conversion and conversion conditions.
 
4) PLC I/O, internal auxiliary relays and timers/counters for distribution.
 
5) lists the output signals of a logical expression, draw a ladder diagram according to logical expressions.
 
6) debugging through simulation, verify that the program is in line with requirements, combined with the experience design was used to further modify the program.
 
(3) examples of sequential logic design
 
1) control requirements. There are A1 and A2, two electric motors, after pressing the Start button, run A1 10min, stop 5min,A2 contrary to A1, A2 when A1 stops running, A1 A2 stops at run time, so the cycle, until the stop button is pressed.
 
2) I/O allocation. X0 as the Start button, X1 for the stop button, Y0 to A1 motor contactor coil Y1 for the A2 motor contactor coil.
 
3) draw sequence diagrams. In order to make the logical relationship clear, running with M0, as an auxiliary relay control relays, and T0 run time control A1, T1 control A1 parking time. Draw sequence diagrams on request, as shown in Figure 5-35. As can be seen from the diagram, blinking T0 and T1 circuits, logic expressions

Ladder Diagram