The document is a student assignment that includes responses to three questions about process control systems. In the first question, the student describes a manual process control system to measure and adjust the pH of a campus lake. The control variable is the pH reading, the manipulated variable is adding an acidic solution, and the disturbance is domestic waste in the lake. The second question asks to automate the control system. The student describes an automatic system with a pH probe connected to a controller that regulates an acid metering pump based on pH readings to neutralize water flowing into a treatment tank before it exits. The third question asks about process control in industries. The student discusses the heating, ventilation, and air conditioning (HV

1. ASSIGNMENT
(JCB 10103)
INTRODUCTION TO INSTRUMENTATION AND PROCESS
CONTROL
NAME: NUR AMIRAH BINTI MOHD ABDUL MANAF
ID NO: (57214115224)
IC: 960103-03-5002
LECTURER: MADAM ERNIE MAZUIN MOHD YUSOF
SUBMITION DATE: 3 NOVEMBER 2015

2. Question 1;
In the campus of UniKL Mitec, we have a nice lake. You are asked to measure the pH of
the lake, and adjust or balance the pH by adding acidic solution. Describe the manual
control system in order to do that. Define your control variable, manipulated variable
and the disturbance.
According to the question, I have been asked to find out and measure the pH value of the lake
and neutralize it by using acidic solution. In order to protect the lake, I need to use the manual
control system to monitor and make sure the reading of the lake is always at neutral state.
Usually, the pH values can be measured by using two methods which is colorimetric method
and electronic method. Colorimetric method is the method that using the pH paper. The pH
paper or colorimetric method is used to find out the colour of the substance. By using the
colorimetric method, we can determine whether the substance is acidic, alkali or neutral state.
However, this colorimetric method is not suitable to measure the water that containing coloured
materials such as organic compounds. As for that, I choose to use the electronic method. Even
though the electronic method is more expensive, but it is more accurate in order to measure the
pH value. So now, I will explain the procedure that I have used to measure the pH meter.
Firstly, I put the pH meter directly into the water-do not need to collect the sample of water.
Before I put the pH meter into the lake, I have checked on the pH meter weather it has the
consistency calibration between other equipment because the calibration can help me to ensure
the data that have collected is accurate. After the pH meter was calibrated, I placed the pH
meter in the lake and the reading of pH meter is recorded. I found that the value of pH meter is
more than 7 which is in the state of alkali. So, I need to neutralize the lake. In order to neutralize
it, the salt solution is added into the lake. After adding it, again, I took the reading of the lake
and find out that the lake is neutral. So, here, I can conclude that, the alkali lake can be
neutralized by adding some salt solution in it. I also found that, the lake might be an alkali
because the lake contain of so many domestic waste that pollute the lake. So, the variables is;
Variables;
Manipulated; the reading of pH meter of the lake
Constant; the acidic solution used to neutralize the pH of the lake
Disturbance; the domestic waste in the lake

3. Question 2;
Make the control from question ‘1’ above to become automatic. In other words, automate
the control of the lake.
+
-
In this system the water flow enter the tank at the bottom and exit the tank through the port at
the top. The pH treatment tank remains full at all time. Therefore the water that flows into the
tank is equal to the water that flow out from the tank. For example, if one gallon of the water
enters the tank, therefore, it will displace one gallon of the water. As the water flow enters the
treatment tank it will be mixed with the tank contents. If the pH of the water varies from the
tank then the water flow will be pH adjusted through the resultant chemical reaction that occurs
as the water mixes with the contents. There will be an equal and opposite reaction within the
tank contents. This opposite reaction is sensed by the pH probe which provides a continuous
pH signal to the pH controller. The controller then paces the appropriate metering pump to
bring the body of water within the tank back into range. As the water flow was alkaline, the
result would be a steady rise in the pH of the tank contents as measured by the pH probe at the
discharge port. The pH controller would then pace the acid metering pump at an appropriate
rate to bring the pH back down into range. So, the pH of water that flow out from the tank will
be at the neutral state as the water have been neutralizing in the tank. After the water flow out,
the next gallon of water will flows into the tank. The same process will repeated if the water
that flow in is an alkali or acid. But, if the water that flow in is at neutral state, the water will
not undergo the same process as it will be automatically discharge from the tank to fill up
another gallon of water.
Water
flows
Acidic
solution
pH reading
of the lake
pH reading
Measuring
device (pH
controller)

4. Question 3;
Control system nowadays are widely being used in many industries. Find 1 industry and
explain its process control.
The industry that I have choose is the automotive industry which use one of the control system
that called heating, ventilating and air-conditioning (HVAC). The vehicle's heating, ventilation
and air conditioning system is composed of three sub-systems that all work together to provide
conditioned air to the vehicle cabin. The heating part takes heat from the engine coolant and
transfers it to the incoming air. The ventilation part moves and directs the air within the cabin
and the Air Condition part cools and dehumidifies the air within the cabin. When they are
working normally they keep you comfortable during all weather conditions. The component of
HVAC include thermostat, lower fan, HVAC control, condenser, evaporator and compressor.
If the components is not functioning, it can cause a lot of heat or no air flow, insufficient cool
air or noises. Most common use in the automotive HVAC system is liquid cooling system. The
cooling system circulates fluid through pipes and passing away in the engine. The engine
absorbs the heat as it passes through the engine to cooling it. After that, the fluid leaves the
engine and transfer to the radiator to exchange the fluid to air.

5. APPENDIX