slides-05

(1)

FALL 2004 MKM 503E MECHATRONIC SYSTEM COMPONENTS

1

ANALOG AND DIGITAL SIGNAL

CONDITIONING: PERFORMANCE

SPECIFICATION AND COMPONENT

(2)

2

PROTECTION:

To prevent damage to the next

element for example microprocessor as a result of

high voltage and high current.

GETTING THE RIGHT TYPE OF SIGNAL:

Making the

signal into dc voltage or current. For example, the

resistance change of a strain gauge has to be

converted to a voltage signal.

GETTING THE RIGHT LEVEL OF SIGNAL:

A signal

from a thermocouple may be a few milivolts. It

shold be amplified to a level that a

microcomputer’s signal level.

(3)

3

ELIMINATING OR REDUCING NOISE:

Noise in the

signal should be elimintated using filtering

techniques.

SIGNAL MANIPULATION:

Transducer output may

have a nonlinear relation with a physical

phenomenon. The ouptu can be linerized using a

proper electronic circuitry.

(4)

4

OPERATIONAL AMPLIFIER

PIN CONNECTIONS OF A 741 OPERATIONAL

AMPLIFIER

(5)

FALL 2004 MKM 503E MECHATRONIC SYSTEM COMPONENTS 5

−

+

= V

V

I

₊

=

0 _I

₋

=

₀

V

_out

+

_

+V

_cc

-V

_cc

V

-V

₊

741 I

₊

I

-IDEAL AMPLIFIER

(6)

INVERTING AMPLIFIER

1 2

Gain

Voltage

R

V

in out

=

−

=

(7)

NON-INVERTING AMPLIFIER

1 2

1 Gain

Voltage

R

V

in out

=

+

=

(8)

VOLTAGE FOLLOWER

in

out

V

=

(9)

SUMMING AMPLIFIER

)

(

2 2 2 C C B B A A out

V

R

V

R

V

R

V

=

−

+

(10)

INTEGRATING AMPLIFIER

∫

−

=

−

2

1

2

1

1 )

(

)

(

t

in

out

v

dt

RC

t

v

t

v

(11)

DIFFERENTIAL AMPLIFIER

)

(

₂ ₁ 1 2

V

R

V

_out

=

−

(12)

12

(13)

13

(14)

(15)

LOGARITHMIC AMPLIFIER

Kat

A

K

V

_out

= ln

+

at in

Ke

V

=

(16)

16

(17)

17

FOCUSING SYSTEM FOR A CD PLAYER

photodiode

array

The light falling on the

diagonally located

photodiodes are compared

comparator

(18)

AMPLIFIER ERRORS

Sliding contact

potentiometer (10 kΩ)

Correcting

the off-set

voltage

Pin-1

Pin-5

741

(19)

19

PROTECTION

Zener Diode Protection

Optical Protection

Zener Diode

optoisolator

LED

Photo

transistor

infrared signal

(20)

MICROPROCESSOR PROTECTION

overvoltage

protection

current limitting

resistor

Polarity protection

(21)

FILTERING

Low-Pass Filter

High-Pass Filter

Band-Pass Filter

Band-Stop Filter

(22)

22

FILTERING CIRCUITS

(23)

FALL 2004 MKM 503E MECHATRONIC SYSTEM COMPONENTS 23 4 3 2 1

R

R =

WHEATSTONE BRIDGE

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

+

δ

=

δ

2 1 1 0

R

V

_s

Balance Condition

supply voltage

Bridge Output

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

+

−

+

=

−

=

4 3 3 2 1 1 0

R

V

_AB _AD _S

Bridge Sensitivity

(24)

24

TEMPERATURE SWITCH CIRCUIT

(25)

COMPENSATION METHODS

sensor

leads

(26)

26