Thursday, June 23, 2011

Using “SavetheDayter” data upload / down tool


Before downloading a new program to controller you must record the settings and manually re-enter after the download.  A tool has been created or use a tool to capture the process and machine parameters before you download, then restore the data after the download – a good tool to use for this is “save the dater”.  It’s use is outlined below.

Using the Save the Dater tool.


Save the Dater will read / write process / machine setup data.
To use the tool first install the application on your computer.  Next run the application and select a topic to connect to your machine’s processor.  The topic must be configured in RSlinx as the tool uses the RSlinx opc topics. you can download save the dayter here
Select a topic: 

Thursday, February 24, 2011

Structure Text Programming

important think that we understand the structure text programming. sometime we use the structure text programming in allen bradley panelview plus to manipulate the instruction and to reduce the plc memory.If you know how to program in any high level language, such as Basic or C, you will be comfortable with Structured Text (ST) programming. ST programming is part of the IEC 61131 standard. An example program is shown in Figure below.
Structure Text Programming
 The program is called main and is defined between the statements PROGRAM an END_PROGRAM. Every program begins with statements the define the variables. In this case the ariable i is defined to be an integer. The program follows the variable declarations. This program counts from 0 to 10 with a loop. When the example program starts the value of integer memory i will be set to zero. The REPEAT and END_REPEAT statements define the loop. The UNTIL statement defines when the loop must end. A line is present to increment the value of i for each loop.One important difference between ST and traditional programming languages is the nature of program flow control. A ST program will be run from beginning to end many times each second. A traditional program should not reach the end until it is completely finished. In the previous example the loop could lead to a program that (with some modification) might go into an infinite loop. If this were to happen during a control application the controller would stop responding, the process might become dangerous, and the controller watchdog timer would force a fault.ST has been designed to work with the other PLC programming languages. For example, a ladder logic program can call a structured text subroutine.you can download the modulle about Structure Text Programming from here and i do hope it can useful for you.

Monday, February 7, 2011

Understanding Array Concept


Array:  a numerically indexed sequence of elements of the dame data type. An array tag occupies a continguous section of memory in the controller with each element in sequence. Array can have one, two or three dimensions.
Element : a single position within an array.
The elements in the array occupy memory in order. The array always start at 0 and extend to the numberof elements minus 1
an array in the tag windows is shown in the following graphic

An array must be created with the following rules in the mind:
  • An array can have up to three dimensions unless it is a part of a structure, where then it can have only  one dimensions.
  • An array can be of one data type only. Array support the following data type:

Thursday, February 3, 2011

USB-to-Data Highway Plus Cable (USB2DHPLUS)

About the Cable
The 1784-U2DHP USB-to-Data Highway Plus Cable allows a customer to connect a computer to a Data Highway Plus (DH+) network via an unused USB port on the computer. You can also use the cable to connect the computer to PLC-5 processors (except for Classic PLC-5 processors, such as PLC-5/10, PLC-5/12, PLC-5/15, and PLC-5/25) or SLC 5/04 processors.

  • Insert the end of the cable having the USB connector into an unused USB port on a computer.
    You see the Found New Hardware wizard.  

  • if you do not see the Found New Hardware wizard, go on to step 9
    on page 7. Otherwise, continue with the next step.
  • Select the No, not this time option and click Next.
  • Select the Install from a list or specific location option and click Next.
  • Select the Search for the best driver option.
  • Check only the Include this location checkbox.
  • Browse to the location where you saved the 1784_u2dhp.inf file and click OK or from program file >RockwellSoftware>RSLinx.
 
  • Click Next.
  • Follow the procedure
  • Click Finish.
there is 2 ways to Configure the cable driver for use with your DH+ networked device
  • DF1 serial 1770-KF2/1785-KE driver for RSLinx Classic Software, Version 2.52 and Earlier.
  • Direct using USB2DHPLUS driver listed on RSLinx configure driver for RSLinx Classic Software, Version 2.53 and Later
for detail information abaut how to install USB2DHPLUS cable you can download from here

Wednesday, January 26, 2011

Creating an IP Address On Control Logix



This is the basic standart knowledge, but i want to share it because i ever get little confusing to create one.
Fisrt you must get serial connection to controller before you setup and IP address to the ethernet modulle.Follow this procedure to create DF1 Communication.
  • Connect your laptop computer to the ControlLogix controller through the serial port, under t he front cover of its main panel.
Serial Port on the ControlLogix Controller
  • Start RSLinx Classic program from Start/Programs/Rockwell Software/ RSLinx/RSLinx Classic.
  • Click RSWho and If there is no serial connection with a file name including DF1, select Communications/Configure Drivers.
  • In the pull down menu labeled Available Driver Types, select RS- 232 DF1 devices and click Add New. Also use this screen to configure other devices, such as Ethernet.

Tuesday, January 25, 2011

Using Ethernet for Industrial Control

Introduction
Ethernet is widely used for information (i.e., office environment) communications today. The technology has availability, familiarity, and cost benefits. Until recently, however, creating an industrial control system using Ethernet was not feasible due to a number of factors, including Ethernet’s lack of determinism, the need for interoperability among devices, and security concerns.

Determinism is the ability to predict when information will be delivered. To guarantee this, an industrial control network must provide scheduled bandwidth (or time slots) that are reserved for time-critical data transfer. Communication over Ethernet, however, is based upon collision detection. If a device attempts to send a message, and that message collides with another message on the Ethernet media, the device backs off and waits to transmit. Thus Ethernet cannot guarantee determinism.

However, recent advances in switch technology have now enabled Ethernet to approach determinism. Switches, unlike traditional bridges and hubs, reduce traffic between the devices attached to their ports. Moreover, the IEEE 802.3 Standard provides for standardized full-duplex operation, which gives a single node - in a point-to-point connection to the switch - full wire concentration. As a result, full-duplex switched Ethernet networks are theoretically able to avoid collisions.

The requirement for device interoperability, the ability of products from different control vendors to communicate with each other, has been answered by the EtherNet/IP (industrial protocol) networking standard. This standard provides interoperability among products from a wide community of automation vendors. It is supported by three major networking organizations: ControlNet International (CI), the Industrial Ethernet Association (IEA) and the Open DeviceNet Vendor Association (ODVA)

ISO/OSI Protocols

ControlNet
The ControlNet network uses the Common Industrial Protocol (CIP) to combine the functionality of an I/O network and a peer-to-peer network. ControlNet take precedence over program uploads and downloads and messaging. Supports a maximum of 99 nodes.
DeviceNet
DeviceNet is mainly used in industrial and process automation. It is based on CAN technology.
It is a low-cost communication link to connect industrial devices to a network and eliminate expensive hard wiring. Power and communication supplied over a 4-wire bus. Supports up to 62 devices on the same bus network.
ModBus
ModBus is an open, serial communication protocol based on the master/slave architecture. The bus consists of a master station, controlling the communication, and of a number of slave stations.
MODBUS is an application layer messaging protocol, positioned at level 7 of the OSI model, that provides client/server communication between devices connected on different types of buses or networks. MODBUS is used to monitor and program devices; to communicate intelligent devices with sensors and instruments; to monitor field devices using PCs and HMIs. MODBUS is an ideal protocol for RTU applications where wireless communication is required.

Sunday, January 23, 2011

Find and Fix I/O Problems

Diagnostic digital modules detect faults and report back.


System designers and end users want to minimise the time it takes to find and fix field device and power supply problems. Using Rockwell Automation FLEX I/O eliminates long wiring runs and reduces terminations per point. But monitoring the condition of I/O and identifying the source of any system failure can be a challenge. Detecting open wire, short circuit and reverse polarity of external power can be tough if you're not right next to the device.

New FLEX I/O diagnostic digital modules (1794-IB16D and 1794-OB16D) detect such faults and report them back to the controller. Once there, they can be monitored via operator panels or a human machine interface (HMI) located remotely.


The FLEX diagnostic modules detect faults such as open/missing input or output field devices or wiring, shorted output field devices, shorted input or output wiring and reverse polarity of user power supply wiring. While they do not check for the presence of the user-supply voltage, this is most easily done by directly wiring the supply voltage to an input channel.

Saturday, January 22, 2011

Adding I/O to ControlLogix Online

Installing I/O to a running controller reduces downtime and expands functionality.

Manufacturers need to update their equipment to increase efficiency, adapt to changing product or process needs, and keep up with regulations. However, many continuous process control applications must run for years without scheduled downtime because shutting down a line leads to significant product loss and lengthy start-up procedures.

To help applications deal with high availability requirements, the newest release of RSLogix 5000 software (v15) from Rockwell Automation allows users to add ControlLogix I/O (Bulletin 1756) to a running Allen-Bradley ControlLogix controller. The new I/O can be added to the same chassis as the ControlLogix Central Processing Unit (CPU), or in a remote chassis connected via ControlNet or EtherNet/IP.

Prior to v15, to expand the system, I/O spares had to be pre-installed into a ControlLogix system or production had to be stopped. If the new I/O were in a remote chassis connected via ControlNet, users would then need to reschedule the network. In addition, if multiple controllers were using the same ControlNet network as the I/O, users also would need to place these other controllers into program mode to complete the network scheduling changes. This meant that trying to expand a single process could result in having to shut down a whole line or even the whole plant.

Friday, January 21, 2011

Troubleshooting an Ethernet/IP System

When troubleshooting any EtherNet/IP system, you must have a logical order to troubleshooting. The order for each troubleshooting issue is dependent on the details for that issue. This TechTip will list and detail, in order of priority, the troubleshooting steps for EtherNet/IP systems.

When troubleshooting Ethernet/IP systems, there are potentially many possible troubleshooting scenarios. In general, there are three types of problems:
  • It does not work at all
    Examples: an I/O node is not connected to a switch (missing cable), cannot ping a node, all MSG instruction to a specific Allen-Bradley® 1756-ENBT ControlLogix® EtherNet/IP Module fails.
  • It works but is too slow
    Example: A resource (PC, controller, 1756-ENBT) in the system is overloaded.
  • It works but fails intermittently
    Examples: The ControlLogix controller outgoing unconnected message buffer is being exceeded, Noise is causing an I/O connection to be lost.
Resolving the Problem
To resolve any of the above problems, you need to know where to look and what to examine. Check all of the following carefully as possible sources of the problem:
  • slow PC or slow application running on the PC
  • node configuration (IP address, etc.)
  • congested network (lots of traffic such as broadcast)
  • slow network (satellite or frame relay)
  • misconfigured switch or router
  • Logix controller resources
    - controller processing capability (5550, 5555, 5563)
    - timeslice for communications
    - cached message queue (32 max)
    - unconnected outgoing buffers (40 max)
  • insufficient processing capability in an ENBT module
  • duplicate IP addresses
  • defective Ethernet network hardware (e.g., cable, switch port, or ENBT module)
  • web server diagnostics or RSLinx® diagnostics

Thursday, January 20, 2011

Configuring an SLC 5/05 Controller's Ethernet IP Address with the BootP Utility

Configuring the IP address for an SLC 5/05 controller can be accomplished in one of two ways, with a serial cable or the BOOTP Server Configuration utility in RSLinx software version 2.42 or later. The BOOTP utility is the less common of the two methods, but it is a convenient tool if the serial port or serial cable is not available.
This Tech Tip Provides instructions on configuring the IP address for an SLC 5/05 controller with the BootP utility. The steps include:
  • Locating the Media Access Control (MAC) address of your SLC 5/05 controller
  • Configuring SLC 5/05 Ethernet communications using the BOOTP Server
  • Configuring a static IP address
Keep the following points in mind before performing the steps outlined in this Tech Tip:
  • It is assumed you have an SLC 5/05 connected to a hub or switch and the computer's networking has already been configured.
  • Use an IP Address of 192.168.2.2 and a Subnet Mask of 255.255.255.0 for the SLC 5/05 controller. Be sure that the IP Address for the computer is on the same subnet as the SLC 5/05 controller (for example, IP: 192.168.2.3 Subnet: 255.255.255.0).
  • If you are not familiar with Ethernet networking, refer to the Microsoft Help section titled, "Configuring TCP/IP" for information on configuring a static IP Address.
  • Always consult your network administrator before making changes to your networking configuration.
The BOOTP protocol is enabled on SLC 5/05 controllers letting the controller query the network for a BOOTP server. If a BOOTP server is present on the network and has been configured with a MAC and IP address for the SLC 5/05 controller, the BOOTP server assigns the configured IP address to the SLC controller. Rockwell Automation does not assign a default IP address to SLC controllers to avoid conflicting with other network devices and causing communication interruptions.

Locating the MAC address for the SLC 5/05 controller.
The MAC address is the hardware address that uniquely identifies each node on the Ethernet network. It is pre-assigned at the factory and is not configurable. Before configuring the IP address for the SLC 5/05 controller, you need to locate and record the MAC address for your SLC 5/05. To do this, use these steps:
  1. Remove power from the SLC 5/05 controller and remove the unit from the rack.
  2. On the bottom left corner of the SLC 5/05 daughter card, locate the small white label printed with a hexadecimal number. The number begins with 00:00:BC.
  3. Record the number on a piece of paper. This number is unique to your SLC 5/05 controller.
  4. Insert the SLC 5/05 controller back into the rack and power it up.

Wednesday, January 19, 2011

Configuring a ControlLogix in RSView Studio via Ethernet

How to configure an application to a ControlLogix Processor on Ethernet in RSView Studio.

This Tech Tip is intended to be used as a guide only. An existing ControlLogix ACD file is recommended. General Ethernet knowledge including knowledge of IP addresses and subnet masks is required for successful Ethernet network configuration. Generic IP addresses have been used. Actual Ethernet configuration will vary.

1. Create a New Application.

Open RSView Studio, click on the New tab.
Assign an Application Name and click Create.
2. Create an RSLinx Enterprise configuration.

In the Application Explorer window click on the [+] next to RSLinx Enterprise to expand the menu. Double click on Communications Setup. Choose Create a new configuration.
The following screen has two tabs:

The Target tab refers to the path of processor that the RUNTIME application will be talking to. This could be running on another Windows 2000/XP machine, a VersaView CE or a PanelView Plus. This setup must be exactly representative of the network this application will be run on, but needs to include only the processor and path to the processor the application will be communicating with.

The Local tab refers to the path of the processor as seen by the DEVELOPMENT computer. This is required when wanting to browse tags in an online Processor.

The Offline Tag File allows the user to browse tags located in an ACD file. This is helpful when a processor is not available online, or the desired application is not in the online processor. Using Offline Tag File requires that a LOCAL path be created even if the processor does not exist or does not contain the same ACD file. Omitting a LOCAL path will result in not being able to browse for tags.
 If the development PC is connected to the processor via Ethernet:
  • Click on the LOCAL tab.
  • Right Click on Ethernet, Ethernet.
    • If Ethernet, Ethernet is not an option, right click on RSLinx Enterprise, (Computer Name), click Add Driver, Click Ethernet, then OK.
  • Click Start Browsing.
  • This will find all compatible devices, including ENET, ENBT, PV+. VersaView CE, and RSLinx Enterprise devices.
  • Click the [+] next to Ethernet, Ethernet
  • Find the IP Address of the ENET/ENBT module and then expand the tree until the processor is visible.
  • Under the Device Shortcuts window, click Add.
  • Change the name of the Shortcut (if desired).
  • Click on the processor.
  • Click Apply.

Tuesday, January 18, 2011

A Quick Tutorial on RSLogix Emulator 5000

RSLogix Emulator 5000 is a software simulator for the Allen Bradley line of Logix 5000 controllers (ControlLogix®, CompactLogix®, FlexLogix®, SoftLogix5800® and DriveLogix®). The goal is to mimic the function of a PLC without the actual hardware and thus do advanced debugging. More information can be found in the AB publication LGEM5K-GR015A-EN-P.
As a quick introduction we’ll go through a simple example of setting up a simulation. This involves three major steps.
 1. Setting up the chassis monitor.
 2.Creating a connection in RSLinx.
3. Creating a project with associated emulation hardware.

Setting up the Chassis Monitor
To start the Chassis Monitor, click Start > Programs > Rockwell Software > RSLogixEmulate 5000 > RSLogix Emulate 5000 Chassis Monitor.
RS Emulator Open
 When the emulator opens up you’re confronted with what looks like an empty chassis.  In slot 0 is an RSLinx module which has to be there for the emulator communications to work.  Your slot 1 might have another irremovable RSLinx module depending if you are running RSLogix Enterprise.

Monday, January 17, 2011

Troubleshooting Faults on SLC Controller

The major error fault code, indicates the probable causes of faults, and recommends corrective action. The following section describes the different ways to automatically clear a fault using your programming software.

AutomaticalIy Clearing Faults: SLC Processors

  • Set the Fault Override at Power up Bit S:1/8 in the status file to clear the fault when power is cycled, assuming the user program is not corrupt.

  • Set one of the auto load bits S:1/10, S:1/11, or S:1/12 in the status file of the program in an EEPROM to automatically transfer a new non-faulted program from the memory module to RAM when power is cycled.
  • Refer to Status Bits for more information on bits S:1/13, S:1/8, S:1/10, S:1/11, S:1/12, S:5/0-7, and S:36/0-7. You can declare your own application specific major fault by writing your own unique value to S:6 and then setting hit S:1/I3.

Saturday, January 15, 2011

PLC Networking to communicate another device

As control systems become more complex, they require more effective communication schemes between the system components. Some machine and process control systems require that programmable controllers be interconnected, so that data can be passed among them
easily to accomplish the control task.

Other systems require a plantwide communication system that centralizes functions, such as data acquisition, system monitoring, maintenance diagnostics, and management production reporting, thus providing maximum efficiency and productivity.

Local Area Networks

The term local area network (LAN) is used to describe a communication network designed
to link computers and their peripherals within the same building or site. A LAN is a high-speed, mediumdistance communication system.

Friday, January 14, 2011

LAN Application in PLC Networking

Centralized data acquisition and distributed control are the most common applications of LANs. Data collection and processing, when performed by an individual controller, can burden the processor’s scan time, consume large amounts of memory, and complicate the control logic program.
A data highway configuration, in which all data is passed to a host computer that performs all data processing, eliminates these problems.
Also, distributed control applications allocate control functions, once performed by a
single controller, among several controllers, this eliminates dependence on a single controller and improves performance and reliability.
To use the distributed processing approach, a LAN and the PLCs attached to it must provide the functions:
- communication between PLCs
- upload capability to a host computer from any PLC
- download capability from a host computer to any PLC
- reading/writing of I/O values and registers to any PLC
- monitoring of PLC status and control of PLC operation
I/O BUS NETWORKS
This network lets controllers better communicate with I/O field devices, to take advantage
of their growing intelligence. This configuration decentralizes control in the PLC system,
yielding larger and faster control systems.
Three types of I/O bus networks:
?Sensor Bus Networks
?Device-level Bus and
?Process Bus.
Sensor Bus Network
At the lowest level of process automation, the Sensor Busses focus solely on discrete devices. AS-I (Actuator Sensor Interface) is the most common Sensor Bus Network.
Field devices typically connected to Sensor Bus Networks include on/off valves, limit switches,….
Device Bus Networks
Device bus networks interface with lowlevel information devices, which primarily transmit data relating to the state of the device (ON/OFF) and its operational status. They used in areas with a high density of discrete devices. These networks generally process only a
few bits to several bytes of data at a time. The most commonly used include DeviceNet
and ProfiBus-DP.

Thursday, January 13, 2011

Introduce to PLCs

What does ‘PLC’ mean?
A PLC (Programmable Logic Controllers)  is an industrial computer used to monitor inputs, and depending upon their state make decisions based on its program or logic, to control (turn on/off) its outputs to automate a machine or a process.
NEMA defines a PROGRAMMABLE LOGIC CONTROLLER as:
“A digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions by implementing specific functions such as logic sequencing, timing, counting, and arithmetic to control, through digital or analog input/output modules, various types of machines or processes”.
Traditional PLC Applications
*
In automated system, PLC controller is usually the central part of a process control system.
*To run more complex processes it is possible to connect more PLC controllers to a central computer.
Disadvantages of PLC control
- Too much work required in connecting wires.
- Difficulty with changes or replacements.
- Difficulty in finding errors; requiring skillful work force.
- When a problem occurs, hold-up time is indefinite, usually long.
Advantages of PLC control
* Rugged and designed to withstand vibrations, temperature, humidity, and noise.
* Have interfacing for inputs and outputs already inside the controller.
* Easily programmed and have an easily understood programming language.

Wednesday, January 12, 2011

RSLogix 5000 Tips and Tricks

Everybody enjoys nifty little tips and tricks to get their work done faster. This listing is for Allen Bradley’s RSLogix 5000 software. Feel free to add your own tips and tricks using the ‘add comment’ link.
General
  • To access Release Notes for this version of software, choose Release Notes from the Help menu.
  • The Quick View Pane, located below the Controller Organizer, provides “thumbnail” information for the selected component.
  • The Watch Pane, located below the language editor window, provides monitoring for all tags referenced in the active routine window.
  • The Controller Organizer is dockable. That is, you can drag it to the left or right side of the screen, or float it somewhere in between.
  • Hide/show the Controller Organizer via a toolbar button to make more display area for editors.
  • RSLogix 5000 supports Cut/Copy/Paste/Drag/Drop of components within the Controller Organizer as well as to other instances of RSLogix 5000.
  • Double-clicking on error messages displayed in the Error Window will navigate you to where the error was encountered.F4 and Shift-F4 can be used to move between errors.
  • You can reorder the columns in the tag editor by clicking on the title and dragging it to a new position.
  • To simultaneously display logic in multiple routines, select Window -> New Window and then arrange the windows manually. Or select Window -> Tile Horizontal.
  • To remove a yellow triangle warning symbol on a device, first check the connection status. If the status is “Connection is not scheduled”, re-open the RSNetWorx software. Return to RSLogix 5000 software and the yellow triangle should be gone.
  • On one computer, you can install and simultaneously launch (run) multiple translated versions of RSLogix 5000 software.
  • Once you do a partial import of rungs, add-on instructions, or user-defined data types, you can’t undo the import. If the import didn’t work as expected, close the project without saving.
  • When you select a partial import, make sure to select the correct rung or trend file. Both files have L5X extensions and the software doesn’t prevent you from selecting the wrong file. If you try to import a rung where a trend is expected, or vice versa, the software does display an error that the import failed.
  • Partial import of rungs works in all ladder routines, including Add-On Instructions.
  • In version 15, the Tag Editor added support for New Window.
  • To simultaneously display logic in multiple routines, select Window -> New Window and then arrange the windows manually. Or select Window -> Tile Horizontal.

Tuesday, January 11, 2011

Establishing a DDE Link to Microsoft


Once a DDE topic is configured, you are ready to establish a DDE Hot Link to Microsoft Excel. There are two ways to establish a DDE Hot Link to Excel, the hard way and the easy way. The hard way is to type it by hand with all the proper syntax marks in place, but we will try it the easy way using the Windows clipboard. The clipboard will copy only hot links.

This exercise will establish a Hot Link to Excel to read a block of five timer accumulators from a Control Logix  and create an active graph of the data in Excel. We will use Timer1 through Timer4 - it is essential that these timers exist in the data table section of the ControlLogix. Excel 97 is used for this exercise, other versions of Excel would be similar with slightly different keystrokes or mouse clicks.

  1. If RSLinx is not already running, start it now.
  2. Select Edit/Copy DDE Link to Clipboard ( or use the icon in the toolbar that looks similar to the typical windows Paste icon.)

Monday, January 10, 2011

100 shortcuts windows

CTRL+C (Copy)
CTRL+X (Cut)
CTRL+V (Paste)
CTRL+Z (Undo)
DELETE (Delete)
SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
CTRL while dragging an item (Copy the selected item)
CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
F2 key (Rename the selected item)
CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text in a document)
CTRL+A (Select all)
F3 key (Search for a file or a folder)
ALT+ENTER (View the properties for the selected item)
ALT+F4 (Close the active item, or quit the active program)
ALT+ENTER (Display the properties of the selected object)
ALT+SPACEBAR (Open the shortcut menu for the active window)
CTRL+F4 (Close the active document in programs that enable you to have multiple documents open simultaneously)

Sunday, January 9, 2011

Dynamic Data Exchange (DDE) and How it works

Dynamic Data Exchange (DDE) is an interprocess communications specification that is built into the Microsoft Windows operating system. It allows Windows programs that support DDE to exchange data between themselves. All communications occur within the Windows environment, essentially transparent to the users, using very simple communication instructions.

Note:

AdvanceDDE protocol is the only version supported by RSLinx-OEM. DDE is
not available with RSLinx Lite.
RSLinx

The easiest way to visualize Dynamic Data Exchange is to think of a conversation between people in a room. These people represent the different Microsoft Windows applications (software programs) running on your computer.

Note:

Not all applications that run under Microsoft Windows support DDE Check with an application’s manufacturer before purchasing an application for use with RSLinx.
DDE Ilustration

Some of the people in the room ask questions (clients), others provide answers (servers), and some both ask questions and provide answers (client/servers).
  • In other words, the client initiates or requests a data transfer and the servers respond to the request by providing or accepting data.

Saturday, January 8, 2011

Free RSLogix 500 Emulator Software

For beginners or users RSLogix500'll often look for versions of the emulator in facilitating understanding of programming RSLogix500, indirectly'll often think where I can get the software. Allen Bradley offers Free RSLogix500 Emulator so that you do not need to require rill PLC for programming .
To get the software you can download

 
http://www.ab.com/programmablecontrol/plc/micrologix/downloads.html

 
Now please try and explore with RSLogix500. But keep in mind is RSLogix 500 emulator does not allow us to do the Run-time Edit. So if we want to change the course we did go offline first and then we'll change our program and then do download the program.  

Hopefully helpful