ELECTRICAL & ELECTRONIC ENGINEERING PROGRAM
FACULTY OF ENGINEERING, UNIVERSITI MALAYSIA SABAH
ENGINEERING LAB 4
KE38101
SEMESTER 5 (2016/2017)
MODULE KL-46105
PREPARED BY:
Navinn a/l Mohanaraj
BK14110172
PREPARED FOR:
IR DR AHMAD MUKIFZA HARUN
Objectives
Study the construction of an LVDT.
Study the characteristic of an LVDT.
Study the signal conditioner for an LVDT.
Study the application of an LVDT.
Equipments
Module KL-64015.
DMM.
Oscilloscope.
Resistor, 220 ohms x 2.
Led, 3mm x 2.
KL-61001A Trainer.
Procedure
Position Detector
1. Module KL-64015 was placed in the Trainer KL-61001A.
2. The connection was completed as below.
Section Area Signal to Section Area Signal
KL-64015 LVDT Vo30-1 -> Amplifier Differential Amplifier V-
KL-64015 LVDT Vo30-2 -> Amplifier Differential Amplifier V+
AMPLIFIER Differential Vo -> Amplifier V+
Amplifier
AMPLIFIER COMPARATOR V- -> VR2
Potentiometer
AMPLIFIER COMPARATOR
AMPLIFIER POTENTIOMETER VR1 -> DC POWER +12V
AMPLIFIER POTENTIOMETER VR3 -> DC POWER -12V
3. The LVDT was moved to the right, DIFFERENT AMPLIFIER (KL-61001A) output Vo=
0.0043V.
4. VR was adjusted so that VK1 is equal to Vo when the displacement is +3mm.
5. The LVDT moved to the left, then to the right, and record then positions at which LED1
and LED2 turned on respectively. 1.2cm
6. VK1 was adjusted randomly and repeat Step 5 several times and record the results.
Digital Position Indicator
1. Module KL-64015 was placed on the Trainer KL-61001A.
2. The connection was completed as below:
Section Area Signal to Section Area Signal
KL-64015 LVDT Vo30-1 -> Amplifier Differential V-
Amplifier
KL-64015 LVDT Vo30-2 -> Amplifier Differential V+
Amplifier
KL-64015 LVDT GND -> GND
DCV&DISPLAY
AMPLIFIER Differential Vo -> DCV&DISPLAY +
Amplifier
3. Set the MODE at SENSOR position and RANGE at AUX position.
4. The output display was recorded for each displacement on Table1 on the result section.
5. Compare readouts to actual displacement.
Computer Control
1. The connection was completed as below
Section Area Signal to Section Area Signal
SINGLE CHIP OUT CONTROL 1 -> Amplifier ALARM SIN IN
KL-64015 LVDT Vo30-1 -> Amplifier Differential V-
Amplifier
KL-64015 LVDT Vo30-2 -> Amplifier Differential V+
Amplifier
KL-64015 LVDT GND -> Differential GND
DCV&DISPLAY Amplifier
AMPLIFIER Differential Vo -> DCV&DISPLAY CONTROL +
Amplifier
2. Module KL-64015 was placed on the KL-61001A and turn on power.
3. Complete Table 2.
Result
Displacement Readout Actual Vo301 (V-) Vo302 (V+)
Displacement
+3 4.242 2.567
+2 3.998 2.840
+1 0812 11mm 3.588 3.277
0 0131 10mm 3.438 3.416
-1 3.283 3.582
-2 3.033 3.830
-3 2.832 4.029
DIP switch 0819 1638 2457 3276 4095
setting (1mm) (2mm) (3mm) (4mm) (5mm)
KL-61001A 1000 2000 3000 4000 -
Out control YES YES YES YES -
pin1
Different 0.964 1.914 2.866 3.777 -
amplifier Vo
Discussion
What is a LVDT stand for? LVDT is an acronym for Linear Variable Differential
Transformer. It is a common type of electromechanical transducer that can convert the
rectilinear motion of an object to which it is coupled mechanically into a corresponding electrical
signal. Basically, it consists of a movable ferromagnetic core and three coils. The primary
winding and the two secondary windings are wound over a hollow coil form made of a
nonmagnetic and insulating material. The oscillating frequency can be determined by the R1,
R2 and C1, C2. R1, R2=10K, C1, C2=0.047micro farad. By using the equation of
is equal to 338.6Hz. To improve the stability of the output amplitude, CR1
and CR2 are connected in parallel with R3 while the transistor constitutes an amplifier for
promoting the driver ability. The rectifiers and filter is to convert AC to DC voltage.
The LED1 and LED2 are used to indicate the core at the left and right respectively. From
this experiment when he LVDT was moved to the right, DIFFERENT AMPLIFIER (KL-61001A)
output Vo = 0.0043V. The output voltage is low and the LED 2 is on. As we can see from the
result when the displacement is +3, +2 and +1 the core is stays at the right hand. This is
because the potential of V- is higher than V+.
The advantages of the LVDT are it is very high range for measurement of displacement
and they can be used for measurement of displacements ranging from 1.25mm to 250mm.
There is no frictional losses too and the input is very high and also the sensitivity. For the
disadvantages LVDT is sensitive to stray magnetic fields so they always require a setup to
protect them from stray magnetic fields. They are also affected by vibrations and temperature
which makes them less efficient. They are some applications of LVDT such they are used where
the displacements ranging from faction of mm to few cm are to be measured. The LVDT acting
as a primary transducers converts the displacement to electrical signal directly.
Conclusion
The LVDT design lends itself for easy modification to fulfil a whole range of different
applications in both research and industry. From this experiment we can see that when the
displacement is higher the output voltage for the amplifier is also higher which is known for
disadvantages of LVDT. We achieved all of the objectives of the experiment.
