Yes I know you got some doubts, I know you don't believe.
I know you think I'm crazy, but I know you're just like me.
Sayin' here we go
Here we go
Here we go again.

("Here We Go Again," by Everclear, 2000)

 

PTOA Segment 10: Control Room Hardware

The study of Process Industry Automation continued with visual aids that showed what board-mounted instruments in a control board panel looked like.

PTOA Readers and Students observed that board-mounted TICs and TRs look significantly different than the local TICs and TRs shown in prior PTOA segments.

The important role of annunciator/alarm panels regarding process control was introduced.

Future PTOA segments will establish that  annunciator/alarm panels are examples of on-off control (as opposed to analog control...but don't stress about that now).

 

PTOA Segment 11: ISA  Symbols are Tell-Tale Signs

The integrated study of Process Industry Schematics (P&IDs) and Process Industry Automation continued and included all 4 Process Variables: Temperature, Pressure, Flowrate, and Level.

PTOA Readers and Students learned how ISA expanded P&ID symbols to differentiate local instruments located in the plant area from board-mounted instruments that would be found mounted in control room panels.

PTOA Readers and Students were challenged to interpret the type and location of several instruments represented on a chart as ISA P&ID symbols.

The exercise was repeated with two schematics that featured temperature-changing equipment called heat exchangers.

The heat exchanger schematic provided an excellent example of a piece of processing equipment working in conjunction with automated instrumentation to control the process variable Temperature.

 

PTOA Segment 12: Enter Computer-Age Process Control

The study of advances in Process Industry Automation continued with an introduction to  Distributed Control Systems (DCS).

The visual differences between digitized and non-digitized control rooms were shown.

PTOA Readers and Students learned that the digitized and non-digitized control rooms are functionally identical.

Both digitized and non-digitized control rooms centralize indicating, controlling, recording, and annunciator/alarm functions. Both digitized and non-digitized control rooms interact with local instruments in the processing area via signal transmission.

 

PTOA Segment 13: The Many Benefits of High Tech Control Schemes

The study of Process Industry Automation continued; the many benefits of Digitized Control Systems (DCS) were illustrated.

PTOA Readers and Students learned that DCS components interact with digital signals in the form of 0s and 1s. These data link signals are transmitted between the field instruments, the control room, and the various DCS components that are distributed throughout the processing facility.

PTOA Readers and Students learned that DCS systems use acronyms like MMI, HMI, GUI that simply refer to how the Control Board Operator receives/observes information in the form of data or graphics on a computer screen and then makes changes via a keyboard or mouse or perhaps a touch screen.

The improved graphics and improved ability to use real-time trend charts in a DCS system greatly advanced the ability to control processing.

 

PTOA Segment 14: I Just Gotta Get A Message To U

The integrated studies of Process Industry Automation and Process Industry Schematics (P&IDs) continued and focused on the ISA P&ID symbols used for process control signal transmission.

PTOA Readers and Students learned how electrical (4-20 mA), data/digital (0s and 1s), and pneumatic (3-15 psi)  signals are represented on P&IDs and viewed visual aids which matched these ISA symbols to the real processing world.

The utilities that support pneumatic, electrical, and data control signals were mentioned:

• Instrument Air Generation and Distribution
• Electrical Generation and Transmission

will reappear in future PTOA Process Industry Utilities segments.

 

PTOA Segment 15:  Yakety-Yak: Signal Transmission on a P&ID

The study of Process Industry Schematics (P&IDs) continued by challenging PTOA Readers and Students to identify digital and electrical signal types displayed on a P&ID excerpt.

The integrated study of the Process Variable Level  challenged PTOA Readers and Students to identify the components of a level control loop and their corresponding signal transmission type.

The exercise showed how each instrument in a control loop shared the same tag number.

The P&ID excerpt chosen for the exercise was found to be faulty; the Level Valve (LV 900) was not tagged and, worse, the transducer (LY 900) was completely missing.

The experience in frustrating, non-updated drawings happens in real life and served as an opportunity for PTOA Readers and Students to use what they know about process automation to determine when a crucial piece of information is missing from a schematic.

 

PTOA Segment 16: Ever-Evolving ISA Symbols

The integrated studies of  Process Industry Schematics (P&IDs) and Process Industry Automation continued via analyzing a real P&ID excerpt that featured Temperature Control Loop 10045 and E-1004 (Exchanger 1004).

E-1004 was introduced as a piece of temperature-changing equipment known as a shell-and-tube heat exchanger.

A visual aid depicting several shell and tube heat exchangers helped PTOA Readers and Students visualize what the symbol for E-1004 on the P&ID excerpt would actually look like in a processing plant.

PTOA Readers and Students learned to identify ISA P&ID symbols for control components located in a DCS; DCS instruments are distinguished with black boxes drawn around the instrument-identifying circle.

PTOA Readers and Students followed a guided study of  Temperature Control Loop 10045.  Each hardware component of the control loop was individually analyzed using a step-wise procedure.

PTOA Readers and Students noticed that the symbol for TIC 10045 had a black box drawn around it; thus, this instrument was part of a DCS.

The exercise provided one more opportunity for PTOA Readers and Students to review control loop tag names and numbers, signal transmission types, and control loop component functions. In this example, the transducer (TY 10045) was present.

 

Congratulations PTOA Readers and Students!

Your self-study of Process Technology and Process Operations
has covered muy mucho industrial processing and operations territory.

Take a moment to glance back over these two
PTOA Review Segments.
Would you have understood the technical terms and concepts
before you began?

Take a moment to pat yourself on the back and then...

Keep up the good work!

 

©2015 PTOA Segment 18
PTOA Deja Vu Review 1-2

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