Lab Report of
Instrumentation
&Control
Submitted by: ALI MAHMOOD
Registration no: 2019-CH-53
Submitted to: Dr. Sidra Jabeen
Lab Safety Rules:
Always wear appropriate personal protective equipment.
Wear lab coat.
Wear close shoes and tie hair.
Don’t wear loose clothes.
Eye goggles should always be worn.
Gloves and apron or lab coat may also be worn when working with dangerous chemicals.
Never taste, touch, or smell any substance, nor bring it close to your eyes, unless
specifically told to do so by your teacher.
Know locations of laboratory safety showers, eyewash stations, and fire extinguishers.
Know emergency exit routes.
No horseplay will be tolerated.
Maintain a clean workspace.
Report accidents if they occur.
Follow work procedures.
Learn how to act in an emergency.
Operate machinery that you are familiar with.
Stay alert and attentive.
Always work in properly ventilated areas.
Do not chew gum, drink, or eat while working in the lab.
Never leave an ongoing experiment unattended.
If you notice any unsafe conditions in the lab, let your supervisor know as soon
as possible.
Experiment #1
Pressure Control Training System
Pressure Sensor
Objective:
To determine the Characteristics of a Pressure transducer
List of Equipment:
Digital Multimeter
Set of Leads
Theory:
Valves:
A valve is a device or natural object that regulates, directs, or controls the flow of a fluid (gases,
liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various
passageways. Valves are technically fittings but are usually discussed as a separate category. In an
open valve, fluid flows in a direction from higher pressure to lower pressure.
Drain Valve
Needle Valve
Air Valve
Drain Valve:
Drain valves remove media from process lines and process or storage tanks. They are used in
applications such as compressed air systems where liquid, gas, or slurries need to drain or be
drained from the system. In this system it is use to cause disturbance.
Needle Valve:
A needle valve is a type of valve which can be used to regulate the flow of a substance, usually
either gas or water, through an appliance or system. The unique feature of the valve is the
inclusion of a small plunger, with a shape akin to a needle.
Air Valve:
Air valves are hydro mechanical devices with an internal float mechanism designed to release
trapped air and wastewater gases during filling and operation of a piping system. They also
ensure air intake during draining to maintain a positive pressure.
Pressure Transducers
A pressure transducer, often called a pressure transmitter, is a transducer that converts pressure
into an analog electrical signal. Although there are various types of pressure transducers, one
of the most common is the strain-gage base transducer.
The conversion of pressure into an electrical signal is achieved by the physical deformation of
strain gages which are bonded into the diaphragm of the pressure transducer and wired into a
Wheatstone bridge configuration. Pressure applied to the pressure transducer produces a
deflection of the diaphragm which introduces strain to the gages. The strain will produce an
electrical resistance change proportional to the pressure.
Types of Pressure Sensor:
There are different types of pressure transducers based on their design. These sensors can come
in several shapes and sizes, but the technology inside can also differ.
There 4 main types of pressure sensor based on this:
Strain Gauge Pressure Transducers
Capacitance Pressure Transducers
Potentiometric Pressure Transducers
Resonant Wire Pressure Transducers
Water Pump Driver
Pump drives take power from an input rotational source and send it to a hydraulic pump. Gears
or other equipment generate the power. Pumps are positioned on the drive housing. A pump
system's rotary power source is referred to as a drive. The term drive signifies motor control
units such as an inverter or starter.
Pressure Sensor
A pressure sensor is a device that detects a force exerted on a surface (pressure) and converts it
to an electronic signal whose strength is relative to the strength of the force. Pressure sensors
can also be used to measure the force exerted.
Procedure:
Connect, through leads, bush No. 8 of the WATER PUMP DRIVER to the bush of
SET POINT 1, bush No. 9 to bush No. 9, bush No. 10 to bush No. 10.
Connect bushes No. 1 and 2 of the PRESSURE sensor to bushes 1 and 2 of the
relevant interface.
Insert one terminal of the digital voltmeter, set in dc, in bush No. 3 and the other one
in the earth bush.
Press the main switch (ON).
Regulate the trimmer OFFSET to read on the multimeter the value 0V.
Start the pump regulating the voltage on SET POINT 1 at 10V.
Read the value shown on the pressure gauge and stop the pump when this value is 1 bar.
Regulate the trimmer GAIN to read on the multimeter the value of 5V: in this case
you have calibrated the pressure sensor establishing, for 0.2 bar, 1 V.
Regulate the valve NEEDLE VALVE for each pressure value and write down the
results read on the multimeter.
Put OFF the main switch.
Remove all the connections.
Draw the diagram of the voltage as a function of the pressure.
Connections shown through diagram:
Calculation:
PRESSURE VOLTAGE
(BAR) (V)
1 5.1
0.9 4.6
0.8 4.1
0.7 3.5
0.6 2.95
0.5 2.35
0.4 1.8
0.3 1.19
0.2 0.65
0.1 0.07
Graph:
Pressure vs Voltage
6
4
Voltage (V)
0
1 0.90.80.70.60.50.40.30.20.1
Pressure (bar)
Objective:
I. To understand the operation of a closed loop ON-OFF control
system using the pressure sensor as a level sensor
II. To understand the effects of the hysteresis on the control
Theory:
Pressure sensor as a level sensor:
Pressure transducers measure level by detecting the pressure exerted by a certain volume of
liquid at the bottom of the tank or well. This is then converted to a level based on a few factors
including: tank type and size, and the specific gravity of the liquid.
On & off control system:
As its name implies, On-Off Control assigns the Controller Output (CO) to one of two positions
such that the final control element (FCE) is either fully open or fully closed. Unlike intermediate
value or PID control, there is not in between.
Closed loop control system:
A closed loop control system is a mechanical or electronic device that automatically regulates
a system to maintain a desired state or set point without human interaction. It uses a feedback
system or sensor. Closed loop control is contrasted with open loop control, where there is no
self-regulating mechanism and human interaction is typically required.
In a closed loop system, the transfer function defines the mathematical relationship between the
input and the output. The change on the output by the input or the relationship between the
detected sensor values is known as the gain of the system. Defining the transfer function of the
system based on the gain and the desired state may require careful calculation for best results.
Hysteresis:
Hysteresis is defined as the deviation of the contact angle from its theoretical (and mean) value
due to physical phenomena like microscopic surface defects and roughness.
Effect of Hysteresis:
In nature hysteresis effects are often caused by phase transitions which are accompanied by
abrupt changes of some of the involved physical quantities, as well as by the absorption or
release of energy in the form of latent heat.
Procedure:
Connect bushes No. 1 and 2 of the PRESSURE sensor to bushes 1 and 2 of the
relevant interface.
Connect bush No. 9 of the WATER PUMP DRIVER to bush No. 9 and bush No. 10 to
bush No. 10 (Sheet 3.1 Fig. 3.1).
Connect the bush of SET POINT 1 to bush No. 4 of the ON-OFF controller and
bush No.3 of the pressure interface to bush No. 3 of the ON-OFF controller.
Insert one terminal of the digital voltmeter, set in dc, in the bush of SET POINT 1 and the
other one in the earth bush.
Press the main switch (ON).
Regulate the voltage on SET POINT 1 at 2V.
Move the terminal of the digital voltmeter to bush X4 of the ON-OFF controller; the
voltage value must be equal to the difference between the voltages applied to bush No.4
and that applied to bush No.3, which is 2V.
Connect bush No.8 of the ON-OFF controller to bush No.8 of the WATER PUMP
DRIVER: the pump will immediately start; the pressure level will increase while the
voltage value, read on the voltmeter, will decrease.
The voltage, at bush X4, once reached the zero value, will bring the ON-OFF controller
output to a voltage of -10V approximately, which will stop the pump.
Gradually turn counter-clockwise the knob NEEDLE VALVE and/or the knob DRAIN
VALVE: as soon as the level slightly decreases there will be a small voltage difference
between bushes No.4 and 3 that will bring the ON-OFF controller output (bush No. 8) to
a voltage of approximately 10V and the pump will start again.
The pump will continue operating until the previous level is reached.
Repeat the procedure from step 12.
Measure the up and down times of the level between start and stop of the pump with an
hysteresis of 0% and write down the results
Repeat the procedure of step 15 for all the values of hysteresis listed in and write down
the results.
For each value of hysteresis repeat several times the measurement of the up and down
times.
Close the valves NEEDLE VALVE and DRAIN VALVE.
Switch OFF the main switch.
Remove all the connections.
Draw the diagram of the characteristic of the hysteresis
Calculations:
For Zero Hysteresis:
Pressure Time
0.65 10
0.6 20
0.75 30
0.8 40
0.6 50
0.8 60
0.75 70
0.55 80
0.6 90
0.6 100
For 30% Hysteresis:
