Transcript PERKEMBANGAN TEKNOLOGI OTOMASI

PERKEMBANGAN
TEKNOLOGI OTOMASI
Priyatmadi
PERKEMBANGAN TEKNOLOGI
1700
1900 20 50
2000
Teknologi Materi
Teknologi Energi
Teknologi Informasi
Automasi
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Apakah Automasi Itu?
Automasi adalah implementasi teknologi kendali
dalam produksi barang dan jasa yang mengambil
alih pekerjaan yang biasa dilakukan oleh manusia.
Klassifisi pengendalian
• Kendali Aritmetika VS Logik
• Kendali Manual VS Otomatis
• Kendali Feed forward VS Feedback
• Kendali Analog VS Digital
Automatic, Feedback&forward, Digital, Arithmetic&logic
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Manual Arithmetic Feedback Control
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Analog Automatic Arithmetic Feedback Control
Cold water in
steam in
hot water out
3-15psi
Set point
TT
I/P
4-20 mA
TIC
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4-20 mA
Digital Automatic Arithmetic Feedback
Control
Cold water in
steam in
hot water out
3-15psi
TT
I/P
DAC
KOMPUTER
4-20 mA
ADC
4-20 mA
Set point
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Arithmetic Feedback Control
Cold water in
steam in
hot water out
3-15psi
Set point
TT
I/P
4-20 mA
e(t)
Set point +
TIC
Controller
4-20 mA
m(t)
Sensor
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c(t)
Plant
CONTROL ACTION
How to compute m(t)
e(t)
Controller
m(t)
ON-OFF
PROPORTIONAL (P)
PROPORTIONAL + INTEGRAL (PI)
PROPORTIONAL + DIFFERENTIAL (PD)
PID
+
AUCTIONEERING
RATIO CONTROL
MODERN CONTROL
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ON-OFF CONTROL ACTION
Set point
r(t)
e(t)
+
-
Controller
c(t)
m(t)
c(t)
Plant
Sensor
m
m(t) = M1 if e(t)>0
m(t) = M2 if e(t)<0
M1
e
M2
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ON-OFF CONTROL ACTION WITH GAP
Set point
r(t)
e(t)
+
-
Controller
c(t)
m(t)
c(t)
Plant
Sensor
m
M1
m(t) = M1 if e(t)>e1
m(t) = M2 if e(t)<e2
e2
e1
M2
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e
Example of ON-OFF action
qi(t)
Level sensor
h(t)
qo(t)
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example
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Proportional Control Action
Set point
r(t)
e(t)
+
-
c(t)
m(t)
Controller
c(t)
Plant
Sensor
m(t)
m(t)=Kpe(t)
e(t)
t
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Integral Control Action
Set point
r(t)
e(t)
+
-
c(t)
m(t)
Controller
c(t)
Plant
Sensor
m(t)=Ki∫e(t)dt
m(t)
e(t)
t
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Derivative Control Action
Set point
r(t)
e(t)
+
-
Controller
c(t)
m(t)=Kd(de(t)/dt)
m(t)
c(t)
Plant
Sensor
e(t)
m(t)
t
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Problem in Analog control
Stability
Sensitivity
Disturbance rejection
Steady state accuracy
Transient response
Noise
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STABILITY
A control loop will be stable if at the frequency of oscillation
that gives a total phase shift of 3600 around the loop, the
gain around the loop is less then 1
Set point
r(t)
e(t)
+
-
c(t)
m(t)
Controller
Sensor
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Plant
c(t)
OUTPUT OF CONTROL SYSTEM WHEN SET POINT IS RISEN
Set point
r(t)
c(t)
e(t)
+
-
c(t)
m(t)
Controller
Plant
Sensor
UNSTABLE
r(t)
n t
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c(t)
SENSITIVITY
Sensitivity is a measure of changes in system characteristic
due to changes in parameters.
Example:
•Load change
•Sensor characteristic change
•Plant characteristic change etc.
Controller can be design to be insensitive to one parameter
but often it must be sensitive to the others.
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Disturbance rejection
The input to the plant we manipulated is m(t). Plant also receives
disturbance input that we do not control. The plant then can be
modeled as follow
plant
D(t)
Gd(s)
Gd(t)D(t)
+
+
R(r)
Gc M(t)
Gp(t)
+
C(t)
–
H
Methods to reduce Td(j)
1. make Gd(s) small
2. increase loop gain by increasing Gc
3. reduced D(s)
4. use feed forward compensation
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Disturbance rejection
Feedforward compensation
Feedforward compensation can be applied if the disturbance can be
measured.
D(s)
plant
Gd(s)
Gcd(s)
Gd(s)D(s)
–
+
R(s)
+
Gc
M(s)
Gp(s)
–
H
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+
C(s)
5.5 Steady State
Accuracy
c(t)
R(t)
E(t)
+
R(t)
Gc
M(t)
Gp(t)
C(t)
ess
C(t)
–
n t
Used integrator to eliminate steady state error but be carefull
system can be unstable
c(t)
r(t)
n t
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Time Response of Control
System
The typical of unit step response of a system is as
c(t)
Mpt
1+ d
css
1.0
0.9
1 d
0.1
Tr
Tp
nt
Ts
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Problem of Noise
Random, meaningless signals can occur in many parts of
control loops. These signals, often referred to as noise,
can interfere with the intelligence of the signal.
For example, heater control the cold water and heated
water may not be completely intermixed by the time they
reach the thermometer bulb. Slugs of cold water may
alternate with hot water to give a rapidly fluctuating,
wholly meaningless temperature signal at the bulb.
If such a noise bearing signal is allowed to reach the
controller, it may result in wild and meaningless
corrections to the process, which may cause fluctuating
or completely unstable automatic control.
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Problem of Noise
Similar noise problems can occur in
connection with most signals, e.g.,
random pulsations in pressure signals,
waves in liquid-level signals,
turbulence in differential-measured flow signals,
and
induced currents in circuits (electromagnetic
wave, lightning, groundloop, etc)
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Solutions to Noise Problem
Derivative action produces difficulties where noise
exists and, therefore, it should generally not be
used in such instances.
Filtering or averaging the noise out of the signal.
For example, in heater control the source of the
thermal noise can be eliminated by better mixing
of the hot and cold water in the tank or by using
an averaging-type thermometer bulb that
measures temperature over a considerable
length instead of at one point.
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Solutions to Noise Problem
Reduction or elimination of the noise at its
source, for example
rotary instead of reciprocating pumps to avoid
pulsating pressures,
larger mixing tanks or surge tanks,
stirrers to obtain a uniform signal,
longer pipe runs and straightening vanes in flow
measurement,
shielding of wires against stray voltages
Use STP wires.
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Ratio Control
In ratio control, a predetermined ratio is maintained
between two or more variables.
Each controller has its own measured variable
and output to a separate final control element.
However, all set points are from a master primary
signal that is modified by individual ratio settings
A typical application of ratio control is the control of
the fuel flow/airflow ratio in a combustion control
system
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Auctioneering Control (Override
Control, Limiting Control)
In suction and discharge pressure compressor
control, the discharge control valve is normally
regulated from the discharge pressure.
However, if the suction pressure drops below its
set point, control is transferred to the suction
pressure controller.
This prevents excessive suction on the supply
side, from demand exceeding supply, with
resultant compressor damage
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Auctioneering Control (Override
Control, Limiting Control)
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Modern Control Action
Fuzzy control
Optimal control
Sliding mode control
Adaptive control (Self tuning control)
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Logic Control
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What is Logic control
Logic control is a control based on a logic concept,
that is the on-off state of variable and/or
equipment
Logic control is often used to control combinational
and/or sequential events such as lift control,
automatic production line, engine start-up, etc.
Originally used device such as switches, relay,
timer, drum, and any other mechanism to enable
changes of the on-off state
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SWITCHES
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Toggle Hand Switches
~
Single pole single throw (SPST)
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Toggle Hand Switches
~
Single pole double throw SPDT switches
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Toggle Hand Switches
DPST
DPDT
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Hand Switches
3PST
Rotary
Swtich
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Push button Hand Switches
Normally open
NO
Normally close
NC
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Push-Push Switch
• This looks like a momentary action push switch
but it is a standard on-off switch:
– push once to switch on,
– push again to switch off.
• This is called a latching action.
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Microswitch
• usually SPDT
• Microswitches are designed
to switch fully open or
closed in response to small
movements.
• They are available with
levers and rollers attached.
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Keyswitch
• A key operated
switch.
• The example shown
is SPST.
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Reed Switch
• Usually SPST
• The contacts of a reed switch
are closed by bringing a
small magnet near the switch.
• They are used in security
circuits, for example to check
that doors are closed.
• Standard reed switches are
SPST (simple on-off) but
SPDT (changeover) versions
are also available.
• reed switches have a glass
body which is easily broken!
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DIP Switch
• DIP = Dual In-line
Parallel
• This is a set of
miniature SPST on-off
switches, the example
shown has 8 switches.
• The package is the same
size as a standard DIL
(Dual In-Line)
integrated circuit.
• This type of switch is
used to set up circuits,
e.g. setting the code of a
remote control.
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Multi-pole Switch
• The picture shows a 6pole double throw
switch, also known as a
6-pole changeover
switch.
• It can be set to have
momentary or latching
action.
• Latching action means it
behaves as a push-push
switch, push once for
the first position, push
again for the second
position etc.
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Multi-way Switch
• Multi-way switches have 3 or more conducting
positions. They may have several poles (contact sets).
A popular type has a rotary action and it is available
with a range of contact arrangements from 1-pole 12way to 4-pole 3 way.
• The number of ways (switch positions) may be
reduced by adjusting a stop under the fixing nut. For
example if you need a 2-pole 5-way switch you can
buy the 2-pole 6-way version and adjust the stop.
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Process Operated Switches
These switches is constructed using one of the
above switches. A process variable will initiate a
displacement to switch the switch
Limit switch
Proximity switch
Pressure switch
Level switch
Temperature switch
Flow switch
etc
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SWITCH CAPACITY
On a switch usually there is a label informing the voltage
and current capacity, e.g.:
250 V
5A
It means that:
the maximum current allowed to pass the switch is 5 A.
The maximum voltage across its terminal allowed is 250 volt
I<5 A
~
~V<250 V
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RELAY
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Relay
Picture is downloaded from www.kpsec.freeuk.com/components/relay.htm
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Relay
NC contact
NO contact
coil
RELAY
A relay is an electrically operated
switch.
Current flowing through the coil of
the relay creates a magnetic field
which attracts a lever and
changes the switch contacts.
The coil current can be on or off so
relays have two switch positions
and they are double throw
(changeover) switches.
Relay consist of coil and contact
Usually a relay has 1 coil and many
contacts both NO and NC
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Relay
In electrical diagram relay is symbolized as shown
A relay can have many contacts both NO and NC
The coil of a relay typically passes 30mA for a 12V relay,
The contacts can drive 5A or more depending on the size of
relay
contacts
coil
NO
NO
NO
NO
NC
NC
RELAY SYMBOL WITH 8 CONTACTS
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NC
NC
Relay
30 mA
R12
R11
5A
R1
~ 220V
12 V
Relays allow one circuit to switch a second circuit
which can be completely separate from the first.
For example a low voltage battery circuit can use a
relay to switch a 220V AC mains circuit.
There is no electrical connection inside the relay
between the two circuits, the link is magnetic and
mechanical. N
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Ladder diagram
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Ladder Diagram
To make such as previous diagram easier to
read a ladder diagram is used
+
S
R1
R11
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Basic logic
+
AND LOGIC
s1
s2
L
Lamp L will light if switch s1 and s2 are on.
In logic on usually symbolized as 1 and off as 0.
s1
0
s2
0
L
0
0
1
0
1
0
0
1
1
1
Mathematically written as
L = S1 AND S2
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-
Basic logic
+
s1
OR LOGIC
L
s2
Lamp L will light if switch s1 OR s2 are on.
s1
0
s2
0
L
0
0
1
1
1
0
1
1
1
1
Mathematically written as
L = S1 OR S2
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-
Basic logic
+
s1
NOT LOGIC
R1
R11
L
Lamp L will light if not R1 is on
R1
0
L
1
1
0
Mathematically written as
L = NOT(R1)
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-
Combinational logic
Suppose you want to design a safe car with the following criteria:
The gear box (GB) will not engage unless:
1. The safety belt (SB) is fastened and the doors (D1-D4) are locked or
2. The safety system is disable by switching on override switch (OS) for
maintenance purpose
Mathematically the above logic is written as
GB = (SB AND D1 AND D2 AND D3 AND D4) OR OS
SB
D1
D2
D3
D4
GB
OS
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Motor Start Stop (sequential logic)
The following ladder diagram is used to
switch a motor on and off
S1
S2
R1
start
stop
R11
R12
R13
motor
Latching action
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R14
Auto start of water pump
Suppose that the motor is
used to drive water pump
and we want that the
pump can run or stop
automatically depending
on the water level
In addition we also want to
override the automatic
control using manual start
and sop control
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LS
Auto start of water pump
Off, manual and auto motor control
O
M
A
S2
S1
R1
start
stop
motor
R11
LS
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Permissive circuits
Often it is desired that a piece of equipment is
allowed to start if several conditions are met.
For example overload switch and over temperature
switch must be closed in order the motor can be
started
Each process condition is called a permissive,
and each permissive switch contact is wired in
series, so that if any one of them detects an
unsafe condition, the circuit will be opened.
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Auto start of water pump with
protection
Suppose we want to protect the motor against over load
and over temperature
Permissive
circuits
O
M
S0
A
S2
S1
R1
start
stop
OL
R11
LS
motor
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OT
Interlock circuits
Often it is desired that only one piece of equipment
is allowed to start if all other equipments are in
off condition.
For example push button circuit used in Quiz show
program where several contestant have to
answer a question.
The first one who pushes the push button will
disable the other’s push button switch
This circuit is called interlock since acting one
circuit will lock the others to function
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Push Button In Quiz Show program
A
B
R21
R11
R12
R1
R2
LA
R22
LB
R13
R23
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Push Button In Quiz Show program
A
R21
R31
B
R11
R31
C
R14
R24
R12
R22
R32
R1
R2
R3
LA
LB
LC
R13
R23
R33
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Push Button In Quiz Show program
Instead of pushing
the PB continually
it is desired that
just pushing once
is enough for the
contestant to claim
that they are the
first team pushing
the button
The presenter must
push the reset
button to reset the
system back to
original state
Reset
A
R21
B
R11
R1
R12
R2
R22
R13
R23
R14
R23
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LA
LB
Interlock
Another example of interlock is the forward circuit of motor
must prevent the reverse circuit, otherwise the motor will
damage
Note:
Motor contactor (or "starter") coils are typically designated by the letter "M"
in ladder logic diagrams.
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Time delay relay
• If the motor is carry a high inertia load it is dangerous to reverse
the direction of the motor instantaneously.
• Time delay relay can be installed to prevent such occurrence to
happen
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Fail safe design
• Consider an alarm
system as shown.
• It can be design in 2
ways
• Both ways work exactly
in the same manner
• The second design
however gives fail save
design.
• Murphy’s law is true. If
something can go wrong
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PLC
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Programmable logic controllers
Before the advent of solid-state logic circuits, logical control
systems were designed and built exclusively around
electromechanical relays.
Relays are far from obsolete in modern design, but have
been replaced in many of their former roles as logic-level
control devices, relegated most often to those
applications demanding high current and/or high voltage
switching.
Systems and processes requiring "on/off" control abound in
modern commerce and industry, but such control
systems are rarely built from either electromechanical
relays or discrete logic gates. Instead, digital computers
fill the need, which may be programmed to do a variety
of logical functions.
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Programmable logic controllers
In the late 1960's an American company named Bedford
Associates released a computing device they called the
MODICON. As an acronym, it meant Modular Digital
Controller, and later became the name of a company
division devoted to the design, manufacture, and sale of
these special-purpose control computers.
Other engineering firms developed their own versions of
this device, and it eventually came to be known in nonproprietary terms as a PLC, or Programmable Logic
Controller.
The purpose of a PLC was to directly replace
electromechanical relays as logic elements with a solidstate digital computer with able to emulate the
interconnection of many relays to perform certain logical
tasks.
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Programmable logic controllers
~220VAC
• A PLC has many "input" terminals
(X), many output terminals (Y).
• The input-output relation is
programmable
• To make PLCs easy to program, their
programming language was designed
to resemble ladder logic diagrams.
• Thus, an industrial electrician or
electrical engineer accustomed to
reading ladder logic schematics
would feel comfortable programming
a PLC to perform the same control
functions.
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Programmable logic controllers
+
A
S1
B
S2
C
• Suppose that the PLC is wired as shown and we want that :
– Lamp A will light if S1 AND S2 is pushed
– Lamp B will light if S1 OR S2 is pushed
– Lamp C will light if S1 EXOR S2 is pushed
Priyatmadi
Programmable logic controllers
+
A
S1
B
S2
C
X3
X4
Y1
LA=X3 AND X4
Y3
LB =X3 OR X4
X3
X4
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Programmable logic controllers
+
A
S1
B
S2
C
X3
X4
Y5
X4
X3
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LC=X3 EXOR X4
Kendali Motor Putar Kanan/Kiri
Kendali logik digunakan untuk proses yang bersifat logik
seperti pengendalian lift.
Dalam praktek kendali logic dan aritmatika digunakan
dua-duanya.
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Milestone Teknologi Kendali
1900
Amplifier tabung
1920
Kendali otomatis menggunakan pneumatik & rele
1940
Supervisory control di jaringan listrik dengan rele
1950
Transistor, komputer, CNC, Electronic controller
1960
DAS, SCADA, PLC, Robot Industri, AI
1970
Distributed Control Systems, VLSI, µP
1980
PC, LAN, Internet
1990
Field bus, Wireless
2000
MEM, Nanotech
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Arsitektur Kendali Proses
Gambar di download dari
http://a1.siemens.com/innovation/en/publikationen/publications_pof/pof_spring_2005/history_of_industrial_automation.htm
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Automasi kedepan
• Tecnologi baru dalam pembuatan sensor MEM
dan sensor nanotech akan mendorong automasi
yang lebih kompleks
• Embeded system akan semakin banyak
digunakan untuk aplikasi otomasi
• Sistem waktu nyata semakin mudah
direalisasikan dengan pemroses yang semakin
cepat dan paralel untuk implementasi
pengendalian yang kompleks
• Automasi masa depan akan diperani oleh
nanotech, wireless networking, dan sistem
adaptif kompleks
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IMPIAN AUTOMATIONIST
Full automation di semua bidang seperti
•
•
•
Sopir
Jurumasak
Polisi
Yang dilakukan oleh mesin otomatis
Ini berarti bahwa Mesin harus secerdas
manusia
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Perbandingan Kecerdasan Mesin
dan Manusia
Bidang
Mesin
Manusia
Perhitungan
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Pengenalan, pemahaman
*
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Perasaan
-
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Keinginan, kemauan
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