Control Valve

The last week of my training, I'd learned about he structure of the control valve. There are 2 types of valves in general: ON/OFF valve and Control valve. The difference between the two is that the ON/OFF valve can only be open or close, while for the control valve, the user can decide how many percent they want the valve to be opened.

The control valve is controlled by the power supply from the range of 4mA-20mA, which represents:
4mA - 0%
8mA - 25%
12mA - 50%
16mA - 75%
20mA - 100%

On a control valve, there were 2 inputs and 2 outputs. The 2 inputs refer to the pressure supply and the power supply. The 2 outputs is main to open and close the valve. 1 output is use to open the valve and another is used to close the valve. Below are the operation of a control valve.

A constant pressure inject to the positioner of the valve. The positioner will refer to the power supply (control variables) to it. If the supply is 4mA, then the positioner will gives an instruction and transfer the pressure into the output to close the valve. On the other hand, if the power supply received is 12mA, which gives an instruction to open the valve 50%, then the positioner will inject the pressure into the output where used to open the valve and stop opening the valve when it reach 50%.

AC Drives troubleshooting

Basically this week, I'm helping one of the supervisor in the instrument department, Mr. Lee Yoon Kian to troubleshoot the AC Drives. The AC Drives that are malfunction will be sent to the instrument calibration room for maintenance.

First of all, Mr. Lee checked all the I/O control cards in the AC drives to make sure that all the I/O control cards are good in condition. If the cards were burnt, the new I/O card will be replaced. If the cards are OK, then Mr. Lee will proceed to the next steps. He will start checking the IC on the control card. In some cases, the control card is OK, but the problem happen on the IC on the board, which may be burnt or spoiled, result the control card couldn't function well and causing the malfunction of the AC drives.

If the problem still haven't detected after troubleshooting the control cards and ICs, he will start checking the parameters in the ICs. Due to some technical problems, sometimes the codes and the parameters in the IC will be imprecise and incompatible with the motors and drives. So the new parameters have to be re-uploaded into the IC using the DMS software, a software used to download or upload parameters from/to the IC.

Until here, if the problem still couldn't be identified, he will check the chopper part and the transformer in the AC drives. The capacitor banks in the chopper will be opened up to determine whether the capacitor banks are still functionable or whether the terminal + and — are connected in the right manner, or the types of capacitor banks is correct (Ex: 15µF). To make sure every steps he performed are correct, he usually accompany a user manual with him because the AC Drives use a very high voltage and power. It will be dreadful if anythings go wrong~

DC Drive Training By Yaskawa

I had attended a training about DC Drive conducted by the Yaskawa Electric (S) PTE LTD supplier. This was a 2 days training program which included classroom training and the site training. Actually, this training is main for the engineers and technicians who are going to deal with DC Drive in the DC Drive control room and I'm so lucky to be picked to join the training together with the professionals. We had been introduce to the basic concept of the DC drive in the classroom training and a presentation about the concept was presented by the supplier as well.

DC Drive are the DC motor speed control system. Since the speed of a DC motor is directly proportional to armature voltage and inversely proportional to the motor flux (which is a function of the field current), either armature voltage or field current can be used to control the speed of the DC motor.

The advantages of the DC drive over direct drive to motor are:

1. smoother operation
2. acceleration control
3. different operating speed for the each process recipe
4. compensate for changing process variables
5. allow slow operation for setup purpose
6. adjust the rate of production
7. control torque or tension
8. saving energy

Besides that, the trainees also been taught the method to troubleshoot the problems of the DC drive. The trainer provided us a guideline and a table contains the symptoms of the failure and the remedy to solve the problems. During the the site training, we got to try on setting up the parameters and settings of the drive. However, due to some improper use of tools and improper construction of circuits, the motor did not work in the way we desired and there were sparkings appear on the motor!! Scary~ I was really really afraid there's gonna be some sort of explosions happen on tat moment, however the power supply quickly been turn off by the experience technicians and everything stop till there.

Well, it do remind me again the important to use the proper tools when you deal with circuit and electricity AND....
Make sure all the cables and electric components are connect in the way they should be connected before you turn the power on... or else
the sorrows of life may just happen like that...... unexpectedly!
hahaha~

ABB Smart Client

Last week was the week that I've been introduced to a brand new drive software, the ABB Smart Client. It is actually a browser based thin client for displaying information from System 800xA. It utilizes the extended automation capabilities of the System 800xA technology to provide intelligent data access and viewing functions to assist all levels of personnel in making quick, informed decisions, taking appropriate action, and thereby improve the performance. The display are available inside and outside the plant facility, as long as the connection to the plant exist.

There are a lots of function can be performed by this software but I could only mastered the Smart Client graphics for the moment. It is very easy and simple to build the display. By just using the System 800xA property Browser and the Smart Client Graphics Palette, I managed to select the information I wanted to add and drag it to the graphic element for display. The display element such as motors, tanks can be selected from the control toolbox. As mentioned previously, the elements selected can be added by simply drag it and put it on the design page. Once the display elements were dropped on the template, it can be resized, aligned, grouped or ungrouped. Same procedures used when we want to select the parameters and reading of the motors or other display elements. By using the System 800xA Property Browser, we can get the data we required, drag it and drop it on the design template. The data selected will be displayed as well.

The SAP (System, Application and Products in Data Processing)

This week, I had been introduced to a new software, known as SAP (System, Application and Products in Data Processing). SAP company application provide the capability to manage financial, asset, cost accounting, production of operations, materials, personnel, plants and achieved documents.

The process flow using SAP included:

1. creating the maintenance notification
2. processing the malfunction report and identifying Paper Mill tasks
3. completing the task
4. closing the report

In order to give me a clearer understanding about SAP, my Supervisor, Mr. Ten Kok Wai had given me the PM Module terminology to me as reference:

1. Notification- a nonfinancial transaction used to report a problem, request work or record an event or activity. It contains elements, descriptions, functional location, priority, source(reported by) and main work center.
2. Work order- a financial and work management transaction used to plan and change labor, material and services.
   
3. functional location- represents the place at which a maintenance task is to be performed and basically it contains the information such as which building, floor or room.
4. Equipment- individual, physical object that is to be maintained as an autonomous unit.
   

the shut down

Last thursday was the day where the factory shutted down the Paper Mill 1 machines for maintenance and to clear the residue in the water tanks. I had been assigned to follow another senior in the department, Mr.Fendi to clear the residue and check the condition of the paddle guides.

To clear the residue, the valve under the water tank was opened in order to let the residue in the water tanks flow out from the tanks and into the drain prepared. After the tanks were emptied, the valve were closed again and the clean water refilled into the tanks again. The workers cleaned up the residue using the waterjet hose after that.

For the paddle guides checking process, it included to check the alarm systems of the paddle guides and to make sure whether the paddles are right in its tracks. There are 2 switches placed beside the paddle. 1 is the limit switch and the other 1 is the shut down switch. these2 switches are connected to an alarm system in the control room. In some cases, when the paddles are running and rotating in a very high speed, it may go out of its track and may stuck in the rods and causing process error. Therefore, the limit switch is required to make sure that the paddle is on its track. When the paddle starting to derail, the paddle will touch the limit switch and a warning signal will be sent to the control room to alert the technicians to adjust the paddle's position. However, if the technicians didn't replace the paddle into its track on a range of time, the paddle will touch the shut down switch, and the system will shut down.

To check the alarm system, the technician will pull the limit switch and the shut down switch. Then he will observe the alarm system's monitor in the control room. If the alarm system is activate, it means the alarm system is okay. If the alarm system is deactivate, then further maintenance on the alarm system should be made.

first day of mine

yesterday was my first day of my internship
well~
maybe due to some kinda nervousness and anxious
i couldnt get a sweet and nice sleep on the previous night
hahahahahaha
i think most of my friends felt tat way too
coz this is the first time we are really involving ourself in the real plant and field

unlike most of my friends who need to prepare their attire themselves
my company, which is GS Paper & Packaging Sdn. Bhd. do prepare the full and complete uniform to every single employees in the corporation

the set of the uniform included:

1. a T-shirt
2. a Hi-Vi Jacket
3. a deep colour pant
   
4. Safety Helmet
5. Safety Shoe
6. Goggle
7. Ear plug
   

and the look I'm dressing in my uniform was shown above
haha

well~
the first day
It was really challenging to me!
after reported myself on the HR department
I was allocated to the Instrument Department
which dealing with all sort of devices, components, tools, equipments which require to operate the machine of the paper mill orderly and unmistakable

before I start my job,
one of the engineer there, I called him as my senior
brought me to have an on-site visit
It was really impressing and unbelievable!
I felt like I was in a James Bond or a Jacky Chan movies on tat moment!!

I saw a HUGE HUGE HUGEx100000000 machine operated in front of me!
so unreal~
since the process of producing the paper is a one-way process or "one-shot process"
it does not separate to many parts of process...
which means the input of the machine is the paper pulp
and the output of the machines will be the end product (recycled paper) already!!
so the HUGE machines is a combination of many many many giant gear wheels, spare parts, devices, components and pulp tanks

please visualize
so many things combine together
it became Huge!
there's no other adjectives I can describe tat "thing" other than *Huge*
haha
to give u a better understanding about the size of the machine
I ll make it a little bit "solid" for u
it is about the length of 7-8 terrace houses!

believe it~
O(∩_∩)O~

After all tat
I have been introduced to all sort of components in the workshop
converter, inverter, actuator, "pressure meter", temperature sensor, power supply, driver, calibrator, transmitter, transformer, potientiometer, limit switch, motor..... etc(x10000)
and i was like a little kid staring at those materials and elements because I didn't see almost all the instruments there
no even heard about their names since I was born

it do consumed some of my brain memory spaces on memorizing tat!

And
that was my first day in my field
sound interesting rite, doesn't it?!

looking forward for more adventures on the coming days~
haha