Instrument Technician Protocols - Part A

Flashcards for reviewing digital communication protocols in industrial communication systems.

What is the main outcome of completing this module?

To apply protocols between devices as used in industrial communication systems.

What is objective one of this module?

To describe and compare the capabilities of digital field devices to that of analog devices.

What are the three types of field device communication systems?

Analog, digital, and hybrid analog and digital communication.

What capabilities does a microprocessor enable in modern field devices?

High measurement accuracy, measurement compensation, sensor linearization, and flexibility in sensor type.

What are the advantages of analog communication systems?

Easy installation and maintenance, high reliability, and faster update rates.

What are the disadvantages of analog communication systems compared to digital systems?

Inability to detect errors, simplex communication, limited diagnostics, on-site device configuration, and measurement error from converters and resistors.

What is the most common type of diagnostic available in analog communication systems?

The transmitter indicates to the control system that a critical failure has occurred and its signal is no longer reliable.

Where can measurement error be introduced in analog communication systems?

The DAC, loop resistor, and ADC.

What are the advantages of digital communication systems compared to analog systems?

Error detection, duplex communication, advanced diagnostics, remote device configuration, multidrop capability, and increased measurement accuracy.

What are the disadvantages of digital communication systems compared to analog systems?

More complicated protocols and rigid hardware and design specifications.

What error detection method is used by all industry standard fieldbus protocols?

A block check character (BCC).

What are the benefits of duplex communication with field devices?

To query advanced diagnostics, remotely configure or calibrate the device, and validate data transfer.

What are the advantages of multidrop communication?

Less cabling, fewer controller input/output channels, and reduced installation costs.

What is the benefit of hybrid analog and digital systems?

It allows the use of both technologies providing flexibility.

How does a hybrid analog and digital fieldbus, such as HART, work?

Superimposing a modulated digital signal onto a current signal.

What is an open communication protocol?

One where the protocol specification is publicly available.

What is a proprietary communication protocol?

One where the manufacturer holds the protocol specification in confidentiality.

What are the advantages of open protocol specifications?

More integration options, less reliance on a single vendor, predictable design, and greater likelihood of adoption.

What are the disadvantages of open protocol specifications?

Less flexibility, less efficiency, and potential compatibility issues.

What are the advantages of proprietary fieldbus protocols?

Seamless integration, higher reliability, and higher efficiency.

What are the disadvantages of proprietary protocols?

Fewer options, more reliance on a single vendor, less likelihood of adoption, potential for obsolescence, and troubleshooting difficulties.