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PLC Automation, PLC Logic, Omron PLC

PLC Automation, PLC Logic, Omron PLC

Recent years, PLC Automation is more and more necessary in Industrial, or in our daily life. So we need to talk about something named PLC Logic. As follows, I will take Omron PLC for example.

PLC Automation

plc-automated-systemplc automation

 

PLC automation is used for control of many types of machines. The subject of automation is vast. Automation is the combination mechanization and intelligence. Intelligence of using sensors and data with a logic or computing device to eliminate the need of human control.

Much of automation does not rely on PLCs. Take for instance business automation. Here the mechanization is much less "machine" and really a process. Custom software and other applications are implemented after studying processes to link information together and streamline operations.

Machines assist Humans with many tasks that require strength and repetition. Automation makes machines smart,well as least as smart as the programmer makes them. To add automation to a machine you need a brain of some sort…a PLC for instance. With a PLC, a machine can handle things that a human cannot. Whether the process is too fast, slow, small, big, cold, hot or just too dangerous for humans then an automated machine is the solution.

You also need a bunch of sensors/transducers for sensory data for the PLC. The eyes, ears, and touch if you will of the PLC. The sensors are your PLC inputs which it uses within its program to process and select the outputs. The PLC outputs can be valves, motors, solenoids, servos, lights, pneumatic or hydraulic cylinders. Basically, any device that you would use to give a machine motion or alert an operator you would connect to a PLC output.

Other systems that enable automation are embedded processors or micro-controllers. These are used in your homes washer/dyer, microwave oven, dishwasher, and may even your toaster. These hard goods are massed produced and therefore the smaller, less expensive micro- controllers are used. Speaking of homes what about using a PLC for home automation?

PLC Logic

Before the advent of solid-state logic circuits, logical control systems were designed and built exclusively around electromechanical relays. Relays are far from obsolete in modern design, but have been replaced in many of their former roles as logic-level control devices, relegated most often to those applications demanding high current and/or high voltage switching.

Systems and processes requiring "on/off" control abound in modern commerce and industry, but such control systems are rarely built from either electromechanical relays or discrete logic gates. Instead, digital computers fill the need, which may be programmed to do a variety of logical functions.

In the late 1960's an American company named Bedford Associates released a computing device they called the MODICON. As an acronym, it meant Modular Digital Controller, and later became the name of a company division devoted to the design, manufacture, and sale of these special-purpose control computers. Other engineering firms developed their own versions of this device, and it eventually came to be known in non-proprietary terms as a PLC, or Programmable Logic Controller. The purpose of a PLC was to directly replace electromechanical relays as logic elements, substituting instead a solid-state digital computer with a stored program, able to emulate the interconnection of many relays to perform certain logical tasks.

A PLC has many "input" terminals, through which it interprets "high" and "low" logical states from sensors and switches. It also has many output terminals, through which it outputs "high" and "low" signals to power lights, solenoids, contactors, small motors, and other devices lending themselves to on/off control. In an effort to make PLCs easy to program, their programming language was designed to resemble ladder logic diagrams. Thus, an industrial electrician or electrical engineer accustomed to reading ladder logic schematics would feel comfortable programming a PLC to perform the same control functions.

PLCs are industrial computers, and as such their input and output signals are typically 120 volts AC, just like the electromechanical control relays they were designed to replace. Although some PLCs have the ability to input and output low-level DC voltage signals of the magnitude used in logic gate circuits, this is the exception and not the rule.

Signal connection and programming standards vary somewhat between different models of PLC, but they are similar enough to allow a "generic" introduction to PLC programming here. The following illustration shows a simple PLC, as it might appear from a front view. Two screw terminals provide connection to 120 volts AC for powering the PLC's internal circuitry, labeled L1 and L2. Six screw terminals on the left-hand side provide connection to input devices, each terminal representing a different input "channel" with its own "X" label. The lower-left screw terminal is a "Common" connection, which is generally connected to L2 (neutral) of the 120 VAC power source.

PLC Automation, PLC Logic, Omron PLC

Inside the PLC housing, connected between each input terminal and the Common terminal, is an opto-isolator device (Light-Emitting Diode) that provides an electrically isolated "high" logic signal to the computer's circuitry (a photo-transistor interprets the LED's light) when there is 120 VAC power applied between the respective input terminal and the Common terminal. An indicating LED on the front panel of the PLC gives visual indication of an "energized" input:

Output signals are generated by the PLC's computer circuitry activating a switching device (transistor, TRIAC, or even an electromechanical relay), connecting the "Source" terminal to any of the "Y-" labeled output terminals. The "Source" terminal, correspondingly, is usually connected to the L1 side of the 120 VAC power source. As with each input, an indicating LED on the front panel of the PLC gives visual indication of an "energized" output:

In this way, the PLC is able to interface with real-world devices such as switches and solenoids.

The actual logic of the control system is established inside the PLC by means of a computer program. This program dictates which output gets energized under which input conditions. Although the program itself appears to be a ladder logic diagram, with switch and relay symbols, there are no actual switch contacts or relay coils operating inside the PLC to create the logical relationships between input and output. These are imaginary contacts and coils, if you will. The program is entered and viewed via a personal computer connected to the PLC's programming port.

Consider the following circuit and PLC program:

When the pushbutton switch is unactuated (unpressed), no power is sent to the X1 input of the PLC. Following the program, which shows a normally-open X1 contact in series with a Y1 coil, no "power" will be sent to the Y1 coil. Thus, the PLC's Y1 output remains de-energized, and the indicator lamp connected to it remains dark.

If the pushbutton switch is pressed, however, power will be sent to the PLC's X1 input. Any and all X1 contacts appearing in the program will assume the actuated (non-normal) state, as though they were relay contacts actuated by the energizing of a relay coil named "X1". In this case, energizing the X1 input will cause the normally-open X1 contact will "close," sending "power" to the Y1 coil. When the Y1 coil of the program "energizes," the real Y1 output will become energized, lighting up the lamp connected to it:

It must be understood that the X1 contact, Y1 coil, connecting wires, and "power" appearing in the personal computer's display are all virtual. They do not exist as real electrical components. They exist as commands in a computer program — a piece of software only — that just happens to resemble a real relay schematic diagram.

Equally important to understand is that the personal computer used to display and edit the PLC's program is not necessary for the PLC's continued operation. Once a program has been loaded to the PLC from the personal computer, the personal computer may be unplugged from the PLC, and the PLC will continue to follow the programmed commands. I include the personal computer display in these illustrations for your sake only, in aiding to understand the relationship between real-life conditions (switch closure and lamp status) and the program's status ("power" through virtual contacts and virtual coils).

The true power and versatility of a PLC is revealed when we want to alter the behavior of a control system. Since the PLC is a programmable device, we can alter its behavior by changing the commands we give it, without having to reconfigure the electrical components connected to it. For example, suppose we wanted to make this switch-and-lamp circuit function in an inverted fashion: push the button to make the lamp turn off, and release it to make it turn on. The "hardware" solution would require that a normally-closed pushbutton switch be substituted for the normally-open switch currently in place. The "software" solution is much easier: just alter the program so that contact X1 is normally-closed rather than normally-open.

In the following illustration, we have the altered system shown in the state where the pushbutton is unactuated (not being pressed):

In this next illustration, the switch is shown actuated (pressed):

One of the advantages of implementing logical control in software rather than in hardware is that input signals can be re-used as many times in the program as is necessary. For example, take the following circuit and program, designed to energize the lamp if at least two of the three pushbutton switches are simultaneously actuated:

To build an equivalent circuit using electromechanical relays, three relays with two normally-open contacts each would have to be used, to provide two contacts per input switch. Using a PLC, however, we can program as many contacts as we wish for each "X" input without adding additional hardware, since each input and each output is nothing more than a single bit in the PLC's digital memory (either 0 or 1), and can be recalled as many times as necessary.

Furthermore, since each output in the PLC is nothing more than a bit in its memory as well, we can assign contacts in a PLC program "actuated" by an output (Y) status. Take for instance this next system, a motor start-stop control circuit:

The pushbutton switch connected to input X1 serves as the "Start" switch, while the switch connected to input X2 serves as the "Stop." Another contact in the program, named Y1, uses the output coil status as a seal-in contact, directly, so that the motor contactor will continue to be energized after the "Start" pushbutton switch is released. You can see the normally-closed contact X2 appear in a colored block, showing that it is in a closed ("electrically conducting") state.

If we were to press the "Start" button, input X1 would energize, thus "closing" the X1 contact in the program, sending "power" to the Y1 "coil," energizing the Y1 output and applying 120 volt AC power to the real motor contactor coil. The parallel Y1 contact will also "close," thus latching the "circuit" in an energized state:

Now, if we release the "Start" pushbutton, the normally-open X1 "contact" will return to its "open" state, but the motor will continue to run because the Y1 seal-in "contact" continues to provide "continuity" to "power" coil Y1, thus keeping the Y1 output energized:

To stop the motor, we must momentarily press the "Stop" pushbutton, which will energize the X2 input and "open" the normally-closed "contact," breaking continuity to the Y1 "coil:"

When the "Stop" pushbutton is released, input X2 will de-energize, returning "contact" X2 to its normal, "closed" state. The motor, however, will not start again until the "Start" pushbutton is actuated, because the "seal-in" of Y1 has been lost:

An important point to make here is that fail-safe design is just as important in PLC-controlled systems as it is in electromechanical relay-controlled systems. One should always consider the effects of failed (open) wiring on the device or devices being controlled. In this motor control circuit example, we have a problem: if the input wiring for X2 (the "Stop" switch) were to fail open, there would be no way to stop the motor!

The solution to this problem is a reversal of logic between the X2 "contact" inside the PLC program and the actual "Stop" pushbutton switch:

When the normally-closed "Stop" pushbutton switch is unactuated (not pressed), the PLC's X2 input will be energized, thus "closing" the X2 "contact" inside the program. This allows the motor to be started when input X1 is energized, and allows it to continue to run when the "Start" pushbutton is no longer pressed. When the "Stop" pushbutton is actuated, input X2 will de-energize, thus "opening" the X2 "contact" inside the PLC program and shutting off the motor. So, we see there is no operational difference between this new design and the previous design.

However, if the input wiring on input X2 were to fail open, X2 input would de-energize in the same manner as when the "Stop" pushbutton is pressed. The result, then, for a wiring failure on the X2 input is that the motor will immediately shut off. This is a safer design than the one previously shown, where a "Stop" switch wiring failure would have resulted in an inability to turn off the motor.

In addition to input (X) and output (Y) program elements, PLCs provide "internal" coils and contacts with no intrinsic connection to the outside world. These are used much the same as "control relays" (CR1, CR2, etc.) are used in standard relay circuits: to provide logic signal inversion when necessary.

To demonstrate how one of these "internal" relays might be used, consider the following example circuit and program, designed to emulate the function of a three-input NAND gate. Since PLC program elements are typically designed by single letters, I will call the internal control relay "C1" rather than "CR1" as would be customary in a relay control circuit:

In this circuit, the lamp will remain lit so long as any of the pushbuttons remain unactuated (unpressed). To make the lamp turn off, we will have to actuate (press) all three switches, like this:

This section on programmable logic controllers illustrates just a small sample of their capabilities. As computers, PLCs can perform timing functions (for the equivalent of time-delay relays), drum sequencing, and other advanced functions with far greater accuracy and reliability than what is possible using electromechanical logic devices. Most PLCs have the capacity for far more than six inputs and six outputs. The following photograph shows several input and output modules of a single Allen-Bradley PLC.

PLC Automation, PLC Logic, Omron PLC

With each module having sixteen "points" of either input or output, this PLC has the ability to monitor and control dozens of devices. Fit into a control cabinet, a PLC takes up little room, especially considering the equivalent space that would be needed by electromechanical relays to perform the same functions:

PLC Automation, PLC Logic, Omron PLC

One advantage of PLCs that simply cannot be duplicated by electromechanical relays is remote monitoring and control via digital computer networks. Because a PLC is nothing more than a special-purpose digital computer, it has the ability to communicate with other computers rather easily. The following photograph shows a personal computer displaying a graphic image of a real liquid-level process (a pumping, or "lift," station for a municipal wastewater treatment system) controlled by a PLC. The actual pumping station is located miles away from the personal computer display:

PLC Automation, PLC Logic, Omron PLC

 

Omron PLC

USB-CIF02:USB PLC programming Cable for Omron CQM1,CPM1, CPM1A, CPM2A,C200HS,C200HX/HG/HE,SRM1 series

omron plc cableomron plc cable

Price: $50.00 6ES7 972-0BB12-0XA0 button

USB- CIF02:USB interface Omron series PLC programming cable,with communication indicator,cable connection between CQM1,CPM1, CPM1A, CPM2A,C200HS,C200HX/HG/HE,SRM1 series PLC and the computer. After connected with CS1W-CN114 cable,it can also be connected with CS/CJ,CQM1H and CPM2C series PLC. 3 Meters

Introduction

USB-CIF02 programming cable simulates USB port as traditional serial port (usually COM3).The working power supply of this cable is directly from the USB port, but not the PLC programming interface. The two-color LED on the converter box indicates data’s transceiving status.

USB-CIF02 is applicable to Omron PLC,which can directly connect with CPM1,CPM1A,CPM2A,CPM2AH,C200HS,C200HX/HG/HE and SRM1 series PLC; for CS / CJ, CQM1H and CPM2C series PLC , please choose USB-CN226 programming cable, but also can connect with CS / CJ, CQM1H and CPM2C series PLC via CS1W-CN114 cable adapter.

 

Note: USB-CIF02 can not be used to the old model C200H, C_ _ H, C500-AP003, 3G2A5-AP003 series PLC.

Outline configuration:

omron plc

Features and technological index:
● Support USB-CIF02 programming software version: CX-Programmer V1.0 and above
● fully compatible with USB2.0 norms
● USB-bus powered, with current consumption of 50 mA
● Baud rate: 300 bps ~ 1Mbps automatically adapt to the standard baud rate
● Support UART data format: data bits: 7-8; stop bit: 1, 2; check-bit: odd / even / no parity
● Each PC only supports one USB cable programming
● Working temperature: -20 ~ +75 ℃
● Cable length: 3 m; Color: black

Usage:

USB device drivers should be installed before using USB-CIF02 programming cable, which are available on the CD-ROM sold together with the cable. And for the specific installation steps, please refer to the instruction files on the CD-ROM drivers, and details are not necessarily listed here.

After completing Driver installation, the corresponding COM port for the USB-CIF02 programming cable will be displayed in the “Device Manager” of Window. The step next is just to choose this COM port in the programming software and other application software and keep other communication parameters as in the Default settings. And the following steps are exactly the same as in the traditional programming cables with RS232 interfaces.

Long-distance communications:

 USB-CIF02 programming cable does not support long-distance communication. For long-distance communication, RS485/422 communication module can be chosen (model: FS-CIF11), which makes dozens of PLC communicate, with the largest communication range of up to 2 Km.  
Please Note: USB interface cannot be extended.


The quality is guaranteed.It's tested before shippment.Not made by Omron,OEM product as the replacement.

If you'd like to get more, you can click here to visit our company store directly.

 

Pls feel free to contact me if any question.

Tel:86-755-26898905-8002

Email:crystal@kollewin.com

PLC Automation, PLC Logic, Omron PLC

 




What is PLC?PLC Programming Cable and a Interface USB/PPIM+

Rencent years, PLC has become a more and more popular industry. However, what is PLC? This essay will talk about PLC, PLC Programming Cable and a Interface USB/PPIM+.

 

What is PLC?

A Programmable Logic Controller, PLC or Programmable Controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. The abbreviation "PLC" and the term "Programmable Logic Controller" are registered trademarks of the Allen-Bradley Company (Rockwell Automation). PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory. A PLC is an example of a hard real time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result.

PLC Programming

While computers are often used to perform digital functions such as edit digital pictures and digital signatures, some computers themselves can actually take on a digital status. These are known as programmable logic controllers, or PLCs. Programmers work on PLCs to ensure they can operate functionality such as other computers, assembly lines and track lighting in large spaces. PLC programming may seem like learning a whole new language; there are a variety of ways to learn how to start speaking PLC, including both self-paced study and instruction from expert PLC programmers.


Read more: www.profibus-factory.com
 
PLC Programming Cable—A Interface USB/PPIM+
USB PPI+USB PPI+
 

Summary:

USB / PPIM + is the PPI Multi-Master programming Cable which with USB interface, to realize the level conversion and various of PPI protocol conversion from USB to RS485.Many cheap USB / PPI cable on the market simulate USB to virtual serial (COM port) to realize the communications, it’s commonly known as "pseudo-USB interface".

The cable only convert the level from USB to RS485, can only support the normal PPI Protocol. But the USB / PPIM + is the real USB interface cable, without installing drivers, directly use the USB option in STEP7 Micre / WIN software, support PPI, Advanced PPI,and Multiple Master Network Protocol. The cable support the 187.

5 Kbps high-speed communications, and take charge of the Multiple Master Network.

This cable is 100% compatible with Siemens PPI Multi-Master USB Cable 6 ES7 901-3DB30-0XA0, and the only difference is that the work power supply from the computer's USB port through the DC / DC isolation, no longer powered by the PLC port. It’s easy to extend communications distance of the RS485 without considering the power supply. The two-color LED on the converter box indicates data’s transceiving status.

USB/PPIM+ is designed for industrial-type photoelectric isolation cable. USB port and RS485 ports are equipped with surge protection and anti-lightning protection circuitry, which can be Hot plug. It’s applicable to the entire Siemens S7-200 Series PLC It’s particularly suited to the industrial scene which the communications interface is more easily damaged because of the greater interference. The protection circuit ensures the safe operation of the system.

Outline configuration:

signals definition of the RS485-Block (DB9M) of the USB/PPIM+

USB/PPIM+

pin

signal

Description

 

3

RxD/TxD+

Data Line B (RS485 signal positive)

8

RxD/TxD-

Data Line A (RS485 signal negative)

5

GND

DGND

 

Features and technological index:

support USB / PPIM + operating system: Windows2000/Windows XP

support USB / PPIM + programming software version: STEP7 Micro / WIN V4.0 and above, without installing drivers, directly use the USB option in Local Connection.

USB is fully compatible with USB V1.1 norms and USB V2.0

USB bus-powered, 5 VDC, the power consumption is about 100 mA, with over current protection

optical isolation voltage: 1000 VDC (up to 3000 VDC, it should be declared when making an order)

USB port with anti-surge protection, RS485 port with 500 W anti-lightning protection and over current protection

support PPI baud rate: 9.6 Kbps, 19.2Kbps, 187.5Kbps

support the communication protocol: PPI, senior PPI, multi-master PPI.

support long-distance communications, the largest communications distance is 2,000 meters (9.6 Kbps) or 1 km(187.5Kbps).

each PC only supports a USB cable programming

temperature: -20 ~ +75

Cable length: three meters, colors: black

Usage:

1, Enter STEP7 Micro / WIN programming software and click "Settings PG / PC interface", check the "PC / PPI cable (PPI)" and click "Properties…" button.

2,Select "USB" option in "Local Connection".

3, Set up the Station Parameters settings in "PPI" as following: Address: 0, Timeout: 1s .

Set up the Network Parameters in "PPI" in accordance with the needs of you. You can choose any of the following:

Advanced PPI: check the Advanced PPI.

Multiple Master Network: check Multiple Master Network.

General PPI: do not check any of option, which is the default option.

select a baud rate as the same with the PLC. If you do not know that the PLC baud rate can be arbitrary choice one.

Click "OK" button to return to the main menu interface.

4, click on the main menu interface of "communication" button to enter the PLC interface connection, check the "search all baud rate" box, and then double-click on the "Double-click refresh”. After a while of searching ,the PLC model And address and other information will display on the software, it’s means that connect successfully with the PLC. Click the "confirmation" button to conduct upload, download, and other operating.

 

PPI Multi-Master Cable of USB/PPIM+ no longer support the early version of the low CPU21X series PLC.

PPI Multi-Master Cable of USB/PPIM+ do not support Freeport communication and MODEM communication.

Long-distance communications:

The largest communications range between the USB/PPIM+ and PLC are up to 2 kilometers (9.6K bps) or 1 km(187.5Kbps),when external plus terminals 120 ohm resistance is needed to connect between the pin3 and pin8 of the RS485 ports (DB9 Male) to eliminate signal reflection. And a PFB-G Bus Isolators is needed to install at the end of PLC. 0.22 mm2 or more unshielded twisted pair lines are used for Communications. When the distance is longer than the length of cable, a RS485 repeaters (model: E485GP), can be installed in the bus for extending the distance.

Because the power of USB / PPIM + all supplied from the USB ports of the computer, you do not need to consider power supply when extended the length of cable. It’s better than the similar products of Siemens.

Please Note: USB interface cable cannot be extended.

USB/PPIM+

 

The quality is guaranteed.It's tested before shippment.Not made by Siemens,OEM product as the replacement.

USB PPI+BUYNOW-BUTTON2

                             $71.00

If you'd like to get more, you can click here to visit our company store directly.

 

Pls feel free to contact me if any question.

Tel:86-755-26898905

Email:crystal@kollewin.com





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