Control System Lab – II(E)

III BE Electrical VI Semester

Department of Electrical Engineering

M.B.M Engineering College, Jodhpur

Laboratory Report

Of

CONTROL SYSTEM LAB -II

Submitted to: Submitted by:

Mrs. Khamma Kanwar Preeti Tenguriya

(Assistant Professor) Roll No.16UELE8053

Faculty of Engineering & Architecture

J.N.V. University, Jodhpur (Raj.)
2020

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 Control System Lab – II(E)

INDEX
S.No. Experiment Page No. Remark

Object 1 To study the given linear system simulator unit1, 3–5

use it to simulate simulator. First order type 1
system, first order type 0 system, second order
type 0.
Object 2 To study the given PID control unit. Use it to 6–8
obtain a typical second order underdamps
system.

Object 3 To study the given temperature control system 9 – 12

use it to obtain temperature V/S time
characteristics using ON-OFF Controller.

Object 4 To study the given stepper control motor unit. 13 – 14

To learn the construction principle of operation
and working different type of stepper motor.

Object 5 Use DC position control system to perform a 15 - 16

suitable experiment to obtain the step response
characteristics of the system.

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 Control System Lab – II(E)

Object 1: To study the given linear system simulator unit1, use it to simulate simulator.

1. First order type 1 system.

2. First order type 0 system.
3. Second order type 0.

With unity –ve feedback obtain their step response characteristics, comment on the effect of varying
forward path gain on the response of the system.

Apparatus required:
DSO
Function generator
Pen drive of 4 GB or less/ trace sheet

Theory:
First order system:

 There are two types of first order closed loop system can be formed, one using normal time constant
and other using X5 time constant.
 Connect 1V p-p square wave signal to the REF point. Connect the output of gain to normal time
constant. The output of time constant should be connected directly to the feedback node of the error
detector

 Connect one channel of DSO with REF point and other channel at time constant output.
 Vary the gain, and observe the effect at the output of time constant. Trace the wave forms and
calculate maximum overshoot (MP), rise time (tr), peak time (tP), settling time (tS), delay time (td) and
steady state error (eSS).

Second order type 0 system:

 Make the connection of the patch cord as per the block diagram shown below. Follow the same steps as
above.

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 Control System Lab – II(E)

 Observe all the effects and make the tabulation and save the wave forms.
 Try for time constant X5 also

Second order type 1 system:

 Make the connection of the patch cord as per the block diagram shown below. Follow the same steps as
above.

 Make the tabulation and save the wave forms.

 Try for time constant X5 also.

Disturbance Rejection:

 Connect the second order system as shown in the fig. below

 Apply a low frequency disturbance signal (sinewave of 1 V) from function generator at N1 and see its
effect on output. Save the wave form.

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 Control System Lab – II(E)

 Now apply the same disturbance signal at N2, and observe its effect on the output. Save the wave form
and conclude the result.

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 Control System Lab – II(E)

Object 2: To study the given PID control unit. Use it to obtain a typical second order underdamps system and obtain
its step response characteristics. Introduction

A. Proportional control
B. Proportional + integration
C. Proportional + behave bounded is cascade union the plant.
APPARATUS REQUIRED:
PID controller setup,
CRO and
connecting leads.
Theory:
The setup is designed to study performance of analog PID controller with regulated system. The board has
built in signal source, DVM, simulated process and thre adjustable parameters as PID,Pfor proportional gain
, I for integrated gain and D for derivative gain .
three socket are given to add or out any parameter PI &D .threr are two signal sources of squire wave
which is adjustable in frequency (10-40 Hz) and amplitude (0-2 Vpp) and other signal source in shape of
triangular wave to sweep CRO in X- direction. One DC voltage output which is continuously variable
between – 2Vand +2V.
Circuit Diagram:

P I D P
I
D

Relay

Int.
C(s)
Time constt.

Sq. Wave TO CRO Time constt.

TO CRO

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 Control System Lab – II(E)

PROCEDURE:
P control mode: connect the circuit as shown in the figure. Switch over CRO for XY mode. Adjust P control
to 0.1 and note the X and Y values. Increase the value of P and note the results in table. Input 1.0 Vpp ,
squire wave of 50ms . I not connected to adder and D control at 00. switch over CRO in tigger mode and
find out period of oscillation. Switch over again in XY mode and find out percentage over shoot and steady
state error
PI control mode :
connect the circuit as shown in figure set Kp =reading of dial. Kd=00. input signal of squire wave amplitude
= 1Vpp at 20 Hz. Switch over CRO in XY mode. Increase I in steps and note the reading . find the result of Ki
for 10-15 % over shoot with minimum Ess .
PID control mode : connect the circuit as shown in figure. Input =1Vpp squire wave of same frequency
adjust Kp and Ki as table 1 and 2 . increase Kd in steps and note the Ypp and Xpp output from CRO. The
equation of PID controller is
M(t) = Kp e(t) +Ki e(t) dt+ Kd de / dt

Observation Table:
S.No Kp Xpp Ypp OSPP ESSPP

PRECAUTIONS:
1. Do not keep CRO in XY mode for long time.
2. Take the reading carefully and accurately.
3. Apply the required signal to the kit to avoid error.
4. Switch off the kit when not in use.

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DISCUSSION:
In open loop response the plots are performed between Magnitude/frequency and phase/frequency. The
upper curve is for gain/Frequency raised to 9.35 db. The middle curve is for frequency and the Lower curve
is for phase. This shift in gain-cross over frequency and phase Margin is due to applied gain KA.

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 Control System Lab – II(E)

Object3: To study the given temperature control system use it to obtain temperature V/S time characteristics using
ON-OFF Controller.

Components Require

Temperature Sensor LM35, Op-Amp IC (LM324/741), Motor Driver IC L293D, Potentiometer-10k, DC Toy motor,

Propeller, 7805 Voltage Regulator, 100uF Capacitor, Multi-meter (Digital one is Preferred), A Breadboard

Theory:

Basically the circuit switches ON a toy motor fan connected to the motor driver whenever heat is applied to

the temperature sensor unit using say a burning matchstick. The wind from the motor fan would blow off

the matchstick and switches OFF itself automatically.

Here the Temperature is the output to be controlled. A feedback is generated using the sensor which is fed

into comparator which acts as a controller here. And the power is the input.

The Temperature sensor LM35 is very accurate whose output is directly proportional to its surrounding

temperature. For every 1°C of rise/fall in temperature, the output voltage of the sensor varies by 10mV.

Working:

Initially, at room temperature, V1 < V2 and hence the output of the comparator is low so the motor is in OFF

state.

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When heat is applied on the temperature sensor using a burning matchstick, the output voltage of the sensor

V1 gradually increases. This generates a feedback signal. When the output voltage of sensor V1 exceeds the

reference voltage V2 set by the pot, the comparator’s output goes high and hence turns ON the motor

through the motor driver.

When the motor turns ON, It produces high velocity wind and blows off the matchstick. Now since the heat

source is turned OFF, the temperature sensor starts cooling and there by its output voltage V1 reduces

gradually. When V1 falls below the reference voltage V2, the comparator’s output again goes low and hence

turns off the motor. No matter how many times you try, the fire on matchstick put near the sensor will be

blown off.

Advantages of this circuit:

1. No complex circuitry.

2. Cheap

3. No need of any advanced programming or Microcontrollers.

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Circuit Diagram:

Caution:

1. Make sure you keep away from the propeller blades while the fan is in ON state. It may be weak normally

but while revolving at high speed, the propeller can hurt you easily.

2. Since we’ll be using a burning matchstick to apply heat to the sensor so care should be taken. Isolate the

temperature sensor away from any wires or any other components and take some precautionary measures.

Discussion:

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Air conditioner, Heater, Refrigerator works on the same principle but the difference is that it uses

more advance equipments to do the job more precisely. Take the AC for example. You set it to a

particular temperature say 17°C and so the AC works only till it cools down the room temperature

until it reaches the pre-set temperature and then switches off. After a while the temperature would

rise above 17°C and then the AC would again start working only until it brings the temperature to the

pre-set value again.

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 Control System Lab – II(E)

Object 4: To study the given stepper control motor unit. To learn the construction principle of operation and
working different type of stepper motor. Use the unit to perform a buildable requirement to find out the step of a
given stepper.

Apparatus Required:
Stepper control motor unit.

Theory:
The stepper motor is a special type of motor which is designed to rotate through a specific angle called step for each
electrical pulse received from its control unit. It is used in digitally controlled position control system in open loop
mode. The input command is in form of a train of pulses to turn the shaft through a specified angle.

The main unit is designed to interface with µP 8085 kit. The stepper motor controller card remains active while the
pulse sequence generator disabled as given plug is connected with µp interface socket .

The following programme enables the stepper motor to run with µp 8085 kit. For two phases four winding stepper
motor only four LSB signals are required.

Circuit Diagram:

DIRECTION 12 V
CW CCW
FIELD
PHASE
PULSE STEPPER
and
PHASE MOTOR
ROTOR
SEQ
DRIVER
GEN.

Y GRD TRIG

PROCEDURE:
Connect the stepper motor with µp 8085 kit as shown in fig. press EXMEM key to enter the address as given then
press NEXT to enter data .

Address Data:

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 Control System Lab – II(E)

2000 3E 80 MVI A, 80 Initialize port A as output port.

2002 D3 03 OUT 03 OB

2004 3E F9 Start MVI AFA

2006 D3 00 OUT 00 Output code for step o.

2008 CD 3020 call delay delay between two steps.

200B 3E F5 MVI A, F6 Location reserve for current Delay.

200d D3 OO OUT OO Output code for step 1.

200F CD 3020 Call delay delay between two steps.

2012 3E F6 MVI A, F5

2014 D3 OO OUT OO Output code for step 2.

2016 CD 3020 calls delay between two steps.

2019 3E FA MVI A, F9.

201B D3 OO OUT OO Output code for step 3.

201D CD 3020 call delay delay between two steps.

2020 C3 04 20 JMP START Start.

Press FILL to save data to execute the programmed press the key GO .The above programme is to rotate the motor at
a particular as defined by the given address. Changing the following contents will change the motor speed.

Observation Table:

S.No No. of Pulse Displacement Step angle

RESULT: The stepper motor runs as per fed programme.

PRECAUTION:
1. Make the connection of motor with µp kit properly.
2. Feed the programme carefully and correctly.
3. Do not change the motor direction at high speed.

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 Control System Lab – II(E)

Object 5: Use DC position control system to perform a suitable experiment to obtain the step response
characteristics of the system. Determine various time domains performance specifications of the system.

Theory:
A common actuator in control systems is the DC motor. It directly provides rotary motion and, coupled with wheels
or drums and cables, can provide translational motion. The electric equivalent circuit of the armature and the free-
body diagram of the rotor are shown in the following figure.

For this example, we will assume the following values for the physical parameters. These values
were derived by experiment from an actual motor in Carnegie Mellon's undergraduate controls
lab.

(J) moment of inertia of the rotor 3.2284E-6 kg.m^2

(b) motor viscous friction constant 3.5077E-6 N.m.s
(Kb) electromotive force constant 0.0274 V/rad/sec

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(Kt) motor torque constant 0.0274 N.m/Amp

(R) electric resistance 4 Ohm
(L) electric inductance 2.75E-6H

Procedures:

We will want to be able to position the motor very precisely, thus the steady-state error of the motor
position should be zero when given a commanded position. We will also want the steady-state error due to
a constant disturbance to be zero as well. The other performance requirement is that the motor reaches its
final position very quickly without excessive overshoot. In this case, we want the system to have a settling
time of 40 ms and an overshoot smaller than 16%.

If we simulate the reference input by a unit step input, then the motor position output should have:

 Settling time less than 40 milliseconds

 Overshoot less than 16%
 No steady-state error, even in the presence of a step disturbance input
 The above state-space model can also be generated by converting your existing transfer function model
into state-space form. This is again accomplished with the ss command as shown below.
 motor_ss = ss(P_motor);

Discussion:

In general, the torque generated by a DC motor is proportional to the armature current and the strength of
the magnetic field. In this example we will assume that the magnetic field is constant and, therefore,

that the motor torque is proportional to only the armature current by a constant factor as shown in the
equation below. This is referred to as an armature-controlled motor.

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