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Tuesday, April 26, 2016

PLC Communication Protocols

PLC Communication Protocols:

(Fieldbus Communication Protocols)

There are a lot of PLC Communication Protocols out there, especially when you consider the evolution of the PLC to the industrial computer (PAC)  and  Ethernet. But today lets explorer some of the most popular Fieldbus Protocols.

From Foundation Fieldbus protocol to ProiBus, to HART and even ASibus protocol. the above video introduces them all, the Online Fieldbus Training course dives into the details of each. They are often used PLCs to DCS, most common in process industries, but in manufacturing too. Even in building automation systems (BAS).

Because of Fieldbus and other communication protocols and technology, process controllers no longer need to be located close to the process. The analog sensors and actuators can communicate with PLC/PAC over greater distances than if the field device was just hard wired into the PLC analog input or output card.

In order to understand the workings of a Fieldbus based system, the Fieldbus course below first starts with Fieldbus basics teaching you about the various types of signals uses in an automation system. From the 4 to 20ma current loop, to digital signals like Manchester encoding. Bit oriented buses like ASi are covered, byte oriented buses like CAN and DeviceNet, and message oriented buses like Foundation Fieldbus and ProfiBus are discussed.

You'll learn about the various topologies ...master, slave, star, ring, FISCO, etc. Get familiar with DCS architecture, power supplies, troubleshooting, applying Fieldbus in hazardous areas. Even a walk through of a Fieldbus project, from beginning to end! And so much more in this huge course coverall the popular PLC communication protocols.

Hope you like and share the Fieldbus Technology Tutorial video above. Thanks

Don (Follow me on Industrial Skills Training Blog and on Twitter @IndTraining .) Be sure to to stay on top!

Friday, April 1, 2016

Industrial Process Control | Pressure Transmitters

Industrial Process Control

>> Pressure Transmitters |  Differential Pressure Transmitters

Differential Pressure Transmitters
What is a Differential Pressure Transmitters? A sensor to detect and measure process pressure.

The differential pressure transmitters is a sensing element connected by pipe work and flexes in proportion to the pressure. The resulting distortion produces an electric signal that is amplified and converted to a value on a read-out. The process side of the sensor sees the pressure to be measured while the other side is connected to a reference pressure. The reference pressure can be full vacuum, atmospheric pressure or another process pressure. Also  by connecting the differential pressure transmitters across an orifice plate in a pipeline, the pressure difference across the orifice can be put into a formula to calculate flow.

To prevent chemicals from damaging the differential pressure transmitters, a flexible diaphragm made of  materials that protects against pitting and stress corrosion cracking is used. Temperature may also need considered when working with differential pressure transmitters as outside temperature can cause the oil fill expands or contracts giving the sensor distorted and false pressure reading. Of course the sensing diaphragm on which the liquid pressure acts must be kept clean too.

For more about industrial process control sensors, see Instrumentation and Process Control Training article.

Don (Follow me on Industrial Skills Training Blog and on Twitter @IndTraining .) Be sure to to stay on top!