Measurement and analysis

Since I enter the Control and Instrumental department, I had a lot of opportunity to learn about measurement instrument. All these instruments are used to measure temperature, pressure, mass flow rate, volume flow rate, level, filter clog and so on.

First I want to introduce about RTD, resistance temperature detector. It is used to measure temperature with the concept “relationship between resistance and temperature”. Both of these parameters are in proportional, which means, the higher the temperature, the higher the resistance.

Another temperature measurement instrument is thermocouple. It used the seebeck effect to build this instrument where it uses two different metals which bonded together. When the hot junction of the metal is being exposed to certain temperature, voltage will be produced.



On the other hand, other than measuring temperature, we need to measure pressure too. Instrument normally used is differential pressure transmitter. Other then measuring pressure, this instrument can be used to measure level and filter clog too.

Other then all that I mention before this, there are still many transducer that I learned. It’s been a great experience to be in this control and instrumental department, however, my training had almost come to the sixth week. Next week I am going to transfer to electrical department. At here, I wish to thanks to all staffs in this department that had taught me a lot during these six weeks, especially, our “Tok Guru”, Mr. Tawang.

Combustion chamber ball valve operation sequence

Today I learn about ball valve operation sequence which located at the combustion chamber. These ball valves control the amount and the flow of the fuel gas flow into the burner inside the combustion chamber. There are three different modes in the burner. They are diffusion, premix and pilot valve.

For diffusion mode, the fire flame is yellow colour, produce No and Co, burn stable and not complete burning. Premix mode, the fire flame is blue colour, produce less pollution, burn unstable and complete burning. Beside that, pilot node is used to help premix mode to burn in a higher stability.



Because of all these characteristic, diffusion mode is used during start up and shut down of the combustion chamber, while premix and pilot mode are used during normal operation of the combustion chamber.

Hardware and Software

After several days training in C&I department, I observe that every time when the engineer going to work, they will bring some kind of drawing which I don’t really understand. Fortunately, Mr. Tawang gave us some introduction about it today. During the design of this plant’s control and instrumental system, they need to have the hardware and software drawing since this system is very complicated. For hardware drawing it explain about the type of transducer, the connection from field to control room, the location and so on. Workers need it to understand the construction of the instrument that they are going to deal with.

On the other hand, software drawing is the digital logic which connected to a particular transducer. These drawing explain the open loop control, close loop control and protection of the instrument.

All this drawings are kept in tick files in the library which I found very interesting. I wish I could explore more about it in the future.

C&I Structure

So far, I had gone to control room and PCC. These places had a lot of cabinet which control the plant. Today, I had the chance to learn about details of the control and instrumental structure.

The operation condition of the plant is important for the operator to monitor it from time to time, therefore, transducers or sensors like magnetic flowmeter, DP transmitter, RTD, thermocouple, and so on, are connected to every machines in the plant. All these transducers then will convert the paramenters like temperature, pressure, flow rate and so on, into electrical form, then sent it to a card in a cabinet which called the ET 200. Later it will send to PCC automation cabinet, then the data will pass into fiber optic cable and transmit to control room’s busses cabinet. After passing through several server, data will then send to computer to display. This is the general idea of how the data is being processed.

After knowing all this, I realize that, to design a control and instrumental structure is very complicated and it involve a lot of knowledge like mechanical, micro p, digital logic, and so on. This is a good experience for me to know the application of my knowledge learn during university.

DC to DC converter faulty

Another fault notification this morning, I had the opportunity to join the investigation. I followed Mr. Sabrin and Mr. Muzammil to the field. After some investigation, they discovered that the DC to DC converter had some problem. Action to be taken is to replace the converter with a new one. Maybe you will asked, what is the effect of this fault? Actually, there are two DC to DC converters which backup for each other, therefore, even one of the converters doesn’t function, the other one will take over, so, there doesn’t affect the system. This is actually the protection design in this plant.


Performing this job actually needs to be very careful since a single mistake can cause huge unwanted effect like tripping the system. Therefore, there are many precaution procedure need to be taken. Firstly, before performing the task, the particular circuit breaker needs to be disconnected to make sure there are no supplied to the converter, reconfirm which wire to be unplugged and so on.

From the experience today, I realize the important of hardware drawings and software drawings which store in the tick files in library. Finally, I got the opportunity to deal with it, and hopefully I can learn more details in the future.

Another Calibration

Yesterday we learn about pressure transducer calibration, today we had the opportunity to do another one. This pressure transducer is different with the one before, it is a mechanical instrument which called c-bourdon. It used the concept just like the party favor, when the pressure enter the c-bourdon, it will try to straighten out, as a result, it will pull the pointer to the correct scale.



what the engineer do today is to calibrate the pressure transducer. Similarly, engineer attach the handpump and multifuntional calibrator together, and inject pressure. Multifunctional calibrator as reference, they check the scale of c-bourdon. Adjustment is done when necessary.



The c-bourdon shows some error reading, after some maintenance, the error is acceptable. lastly, they attach back the pressure transducer back to the turbine.