What is the DDE Protocol?

The Protocol is nothing but a communication bridge. A communication bridge established between two software devices, or even between two persons can be called a protocol.

DDE was first introduced by Microsoft back in 1987.

So coming on to DDE protocol, DDE stands for Dynamic Data Exchange. As the name indicates, the data can be transmitted from time to time. That means the data can be transmitted or read on a real-time basis since it is a dynamic data exchange.

Dynamic Data Exchange (DDE)

Dynamic Data Exchange (DDE) is an interprocess communication system that allows data to be communicated or shared between the applications in operating systems such as Windows.

Dynamic Data Exchange works based on client and server model communications. The client is the application that is requesting the data and the one that is providing the data is called server. DDE doesn’t use any specific functions or libraries. Which makes it easy for anyone to use this protocol.

DDE can be used to implement a broad range of application features that include linking to real-time data such as stock market updates, scientific instruments, or process control. It is also used in creating compound documents, such as a word processor document that includes a chart produced by a graphics application. In this instance, DDE updates the data on the chart when the source data is changed, while the rest of the document remains the same.

Dynamic Data Exchange makes use of shared memory and a set of commands, message formats, and protocols for communication and sharing.

There are many Automation Softwares that Support DDE protocol for communicating with other software.

Some of them are,

Wonderware Intouch SCADA (Schneider Electric)

RsLinx (Rockwell Automation)

Refer to the following articles to see how the DDE protocol is implemented in automation software.

Comments

What is a Torbar? – Averaging Pitot Tubes

The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...

Ferrules and Cross Ferruling

Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...

Thermowell Insertion and Immersion Length

The thermowell is the industrial housing for temperature elements like RTD or thermocouple or temperature gauges. Thermowell is directly exposed to process fluid/media. Inside the thermowell, element/gauge is installed. Thermowell transfers the heat to the temperature element. Depending upon the element type, the fluid temperature can be known. So Thermowell protects the temperature element against harsh conditions and process fluid. It enables removal of the temperature element for replacement, repair, or testing without affecting the process system. Generally, thermowells are provided with all-temperature Elements like RTD or Thermocouple or temperature gauge. A few exceptions would be bearing RTD, skin type thermocouple, air duct thermometer, etc where thermowell is not applicable / required. When the thermowell assembly is inserted into the pipe, it is subjected to vibration. This vibration is caused by vortices to be generated alternately on either side of the thermowell. The...

TILI Automation

Search This Blog