Would you like to learn to program a plc ?

This test stand is just what you need !!!

This is not a toy. This is a brand new plc made by ge fanuc. Operates on 120 volts ac and has its own built in 24 volt dc power supply to operate the inputs. Its a new series 90 micro with eight 24 volt dc inputs and six outputs. Great for the beginner. Most people cannot afford to buy a used plc and the software to program it because even used plcs cost hundreds of dollars and the software is extra at a thousand dollars or more. With this kit you get everything you need (except the computer) to learn to program a programmable logic controller.

The test stand that allows you to simulate the inputs changing to watch the program control the outputs, the software to load on your pc or laptop, the cable to connect from your pc to the plc and the manuals that show you how its done.....plus the new ge ic693udr001np1 plc. Simply load the software on your computer, connect the cable from the computor to the plc and follow the simple instructions to communicate with and program the controller. You can practice writing simple plc programs and then watch the outputs change based on your inputs and the program you wrote. Its the best way to learn.

More detail you prefer to visit here

Siemens releases new product of Relays

The SIRIUS family of relays offers solutions for monitoring, switching and timing applications and for conversion of analog signals

Monitoring relays have a solution for you, whether its temperature, voltage, current, speed or level. Simple configuration and selectable input sensors make these units a snap to implement.

witching relays offer solutions from a compact housing and DIN rail mounting to high current switching capacities.

iming relays offer flexible input voltages and selectable time ranges. A single unit can match most industrial applications.

Interface converters are used for the conversion of analog signals from field devices to match control system signal levels. For the purposes of electrical isolation, amplification and signal matching, coupling relays and transformers are required between the control system and the peripherals. Sirius Interface converters off a compact size and convenient DIN rail mounting. Several models offer selectable input and output ranges. Manual override switches are also available to put a unit in bypass mode. Bypass mode disables the process input signal allows manual adjustment of the output signal. Making these products ideal for analog signal simulation.

for more detail and see other new product, I suggest you to visit the siemens sitepage

Allen-Bradley control solutions set the standard

Allen-Bradley control solutions set the standard - from the invention of the programmable logic controller nearly 30 years ago to today's open and highly integrated control platforms. The reason? Our control solutions move you forward while protecting the control investment you made in the past. Use our controller selection to find a platform that fits your requirements today.

You're concerned with solving key manufacturing challenges - lower costs, improved throughput, higher quality and increased flexibility. We offer highly integrated control solutions to assure that your control system will be available to solve those challenges.

The benefit to you comes in time savings, cost savings and faster start-ups that result from pre-integrated products designed to work together as well as from services available to you from initial conception to ongoing maintenance.

PLC : A History

In the late 1960's PLCs were first introduced. The primary reason for designing such a device was eliminating the large cost involved in replacing the complicated relay based machine control systems. Bedford Associates (Bedford, MA) proposed something called a Modular Digital Controller (MODICON) to a major US car manufacturer. Other companies at the time proposed computer based schemes, one of which was based upon the PDP-8. The MODICON 084 brought the world's first PLC into commercial production.

When production requirements changed so did the control system. This becomes very expensive when the change is frequent. Since relays are mechanical devices they also have a limited lifetime which required strict adhesion to maintenance schedules. Troubleshooting was also quite tedious when so many relays are involved. Now picture a machine control panel that included many, possibly hundreds or thousands, of individual relays. The size could be mind boggling. How about the complicated initial wiring of so many individual devices! These relays would be individually wired together in a manner that would yield the desired outcome. Were there problems? You bet!

These "new controllers" also had to be easily programmed by maintenance and plant engineers. The lifetime had to be long and programming changes easily performed. They also had to survive the harsh industrial environment. That's a lot to ask! The answers were to use a programming technique most people were already familiar with and replace mechanical parts with solid-state ones.

In the mid70's the dominant PLC technologies were sequencer state-machines and the bit-slice based CPU. The AMD 2901 and 2903 were quite popular in Modicon and A-B PLCs. Conventional microprocessors lacked the power to quickly solve PLC logic in all but the smallest PLCs. As conventional microprocessors evolved, larger and larger PLCs were being based upon them. However, even today some are still based upon the 2903.(ref A-B's PLC-3) Modicon has yet to build a faster PLC than their 984A/B/X which was based upon the 2901.

Communications abilities began to appear in approximately 1973. The first such system was Modicon's Modbus. The PLC could now talk to other PLCs and they could be far away from the actual machine they were controlling. They could also now be used to send and receive varying voltages to allow them to enter the analog world. Unfortunately, the lack of standardization coupled with continually changing technology has made PLC communications a nightmare of incompatible protocols and physical networks. Still, it was a great decade for the PLC!

The 80's saw an attempt to standardize communications with General Motor's manufacturing automation protocol(MAP). It was also a time for reducing the size of the PLC and making them software programmable through symbolic programming on personal computers instead of dedicated programming terminals or handheld programmers. Today the world's smallest PLC is about the size of a single control relay!

The 90's have seen a gradual reduction in the introduction of new protocols, and the modernization of the physical layers of some of the more popular protocols that survived the 1980's. The latest standard (IEC 1131-3) has tried to merge plc programming languages under one international standard. We now have PLCs that are programmable in function block diagrams, instruction lists, C and structured text all at the same time! PC's are also being used to replace PLCs in some applications. The original company who commissioned the MODICON 084 has actually switched to a PC based control system.

PLC : Basic Long Explanation

A programmable logic controller, or PLCS, is a software-based equivalent of a relay panel. A programmable logic controller ( PLCS ) is a general-purpose device. One programmable logic controller ( PLCS ) can be programmed to control a variety of machines, and programs can be changed easily for new jobs or changes in production routines.

Programmable logic controllers ( PLCS ) were once primitive devices capable of providing only minimal feedback about machine operation and status. The situation has changed drastically, however, with the advent of more powerful computer chips and new standards that give a programmable logic controller ( PLCS ) access to information throughout a manufacturing plant. Whereas the first programmable logic controllers ( PLCS ) generally provided only limited information about the status of relay contacts, new monitoring capabilities let the user know exactly what is happening on the floor.

Some programmable logic controllers ( PLCS ) are equipped to solve problems involving mathematical functions such as sine, cosine, tangent, xy, y root of x, e sub x , natural logarithms, and common logarithms. Such calculations are often required for energy management, process control, process modeling, real-time error correction, and many other applications.

And while ladder logic is still the standard industry programming language for programmable logic controllers ( PLCS ), the trend is toward state logic, sequential function charts, graphics, and versions that are programmable in Basic, C, or other high-level languages.

The ability to handle analog signals along with arithmetic and other complex calculations has made programmable logic controllers ( PLCS ) suitable for the control of processes as well as for the control of machines. Typical applications for programmable logic controllers ( PLCS ) are mineral and chemical processing, water and waste treatment, and petroleum collection and distribution. In many of these applications a programmable logic controller ( PLCS ) can complement conventional analog control systems by handling sequence problems as well as a portion of the analog calculation and control. In support of those functions, some programmable logic controllers ( PLCS ) now have the ability to store recipes for batch processing, reducing the need for manual inputs.

In further support of their process-control capabilities, some programmable logic controllers ( PLCS ) can be equipped to solve complex equations such as proportional-integral-derivative equations required for the control of many processes. A sophisticated programmable logic controller ( PLCS ) is capable of performing these calculations on many different portions of a process simultaneously.

Programmable logic controllers ( PLCS ) are also capable of producing analog outputs and of providing position control functions. Programmable logic controllers ( PLCS ) can even provide control functions normally performed by numerical controls.

A modern programmable logic controller ( PLCS ) can also pass information back to the operator. It can print out its own ladder diagram for record, review, or change, or it can provide status or progress reports in English on a CRT or printer routinely or on request. A programmable logic controller ( PLCS ) can also display messages in English to summarize data or guide the operator.

Data-analysis programs are becoming increasingly common. A spreadsheet format is often used. Usually each programmable logic controller ( PLCS ) is assigned a tag or number. Parameters such as data type, coil, input, and addresses are tracked. The programmable logic controller ( PLCS ) initiates changes to data within the computer database, which initiate other control tasks. For example, if the programmable logic controller ( PLCS ) closes a valve, a software routine can be started that measures resulting flow through the valve and sounds an alarm if the flow is not within desired limits.

The programmable logic controller ( PLCS ) also can track down external faults. This capability is useful because the machine and externally mounted control elements such as limit switches, solenoids, sensors, transducers, remote pushbuttons and selector switches are usually much less reliable, and more often a cause of machine downtime than the programmable logic controller ( PLCS ).

Other maintenance aids are available to help solve malfunctions. One feature intensifies on a CRT that portion of a circuit that is carrying current. Another feature lets an operator command specific inputs or outputs to be unconditionally turned on or off, thus helping a technician determine whether a problem is being caused by an internal or external failure.

Programmable logic controllers ( PLCS ) robot control: Programmable logic controllers ( PLCS ) are often equipped with special firmware (software programmed by programmable logic controller ( PLCS ) manufacturers) through which the controllers can perform many complex procedures according to simple instructions in user programs. Sequencer firmware for programmable logic controllers ( PLCS ) provides the programming, storing, and accessing of data required for simulating electronic, or electromechanical sequencers and programmers. Sequencer data are stored in a data-table section of programmable logic controller ( PLCS ) memory, a section separate from that available for user programs. Programmable logic controllers ( PLCS ) containing sequencer firmware are especially useful for controlling robots where the final position of each movement is determined by limit switches or other on-off, position-feedback devices.

Robot movements can be altered by using different masks for different robot tasks. One method of loading or programming sequencers is with a "teach" mode. This is a technique for loading or setting up the on-off contacts in a sequencer to correspond with the on-off status of I/O points. For this method, a robot is jogged into a desired position. Pressing a "teach" pushbutton energizes a sequencer load instruction that causes the on-off status of all pertinent inputs to be copied into a sequencer step. By jogging the robot through steps sequentially, in each case pressing the "teach" pushbutton, a programmable logic controller ( PLCS ) is "taught" a sequence of movements.

Robots having closed-loop systems are controlled by programmable logic controllers ( PLCS ) through digital-to-analog (d/a) I/O modules. These modules convert digital PC signals to analog outputs having ±10-V range. The outputs serve as speed references for the hydraulic or electrical servosystems that typically power each axis. Each axis is mechanically coupled to a potentiometer or encoder that feeds position and velocity data back to a programmable logic controller ( PLCS ), closing a feedback control loop. Digital commands from a programmable logic controller ( PLCS ) to a converter initiates motion, sets acceleration rates, determines speeds, and initiates deceleration. Motion is halted when the feedback indicates the robot has reached the proper position.

Suitably equipped programmable logic controllers ( PLCS ) can generally control point-to-point or vectored motion. Point-to-point movement along each axis is initiated and halted independently of other axes. This type of motion is easily programmed, requires little memory, and is suitable for many robot applications.

Vectored motion, however, requires that the movements along two or more axes be interdependent. The programmable logic controller ( PLCS ) adjusts acceleration rates and speed for each axis so that all movement terminates simultaneously. By this means a robot arm moves from point to point along the shortest path. Vectored motion control usually reduces the time required for each move. To perform vectored control, programmable logic controllers ( PLCS ) must be equipped with arithmetic firmware that calculates speeds required for each axis. Although standardized algorithms are used for these calculations, vectored motion programs are somewhat more complex and require more memory than those for point-to-point motion.

Computers have expanded programmable logic controller ( PLCS ) power through greater speed and programming flexibility. Today's programmable logic controllers ( PLCS ) almost always have a port that permits a user to tie into a computer. Three developments have helped bring about this integration of Programmable logic controllers ( PLCS ) and computers: "smart" programmable logic controllers ( PLCS ) with their own microprocessors and memory, multitasking software, and local-area networks (LANs).

New software has enhanced the capability of computers, particularly personal computers to operate with programmable logic controllers ( PLCS ). Until recently, small computers were limited to performing one task at a time. If a computer was being used to check the status of a programmable logic controller ( PLCS ), it could not perform data analysis or generate a report at the same time. However, with the development of concurrent DOS (disk operating system), the simultaneous juggling of two different tasks can be done.

More powerful microprocessors have resulted in programmable logic controllers ( PLCS ) able to perform multiaxis control and able to link with sophisticated vision systems. One reason new programmable logic controllers ( PLCS ) are taking on such a wide range of duties is that they can be installed in modules, thus simplifying any needed customization and future expansion. Because each programmable logic controller ( PLCS ) contains its own internal communication highway or bus, a programmable logic controller ( PLCS ) can be upgraded with additional memory or processing capability and can be added by snapping in additional modules.

Various programmable logic controller ( PLCS ) modules add RS-232 communication ports, multiaxis control and fault annunciation.

Programmable logic controller ( PLCS ) software can be developed either on or off line; data-management and analysis programs are available. Many of the programmable logic controllers ( PLCS ) can be programmed from an IBM PC or compatible machine, and special industrially hardened programmers are also available when extreme temperature, dust, and vibration are problems. I/O stations can be located up to 2,000 ft from the CPU.

A programmable logic controller ( PLCS ) is no more powerful than the software available for it. Two relatively recent developments for programmable logic controllers ( PLCS ) are menu-driven software and concurrent operating systems, which have simplified programming and made it more useful. Programs using menus allow an operator with only minimal training to monitor, analyze, and manage processes. Concurrent operating systems switch back and forth between two different programs so fast that both appear to be running at the same time.

Programmable Logic Controllers

A programmable logic controller (PLC), is a digital computer used for automation of industrial process, such as control of machinery on factory assembly lines.
The PLCs are widely used in indutrial automation.

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 or non volatile memory. A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.