3. Component’s required
wires(0.5mm)
wires(2.5m)
no & nc element
ryb strip
multi-core wire
different size of pipe
cutter
thimble of various size
crimping pliers
ferrule
fan
tube light
channel
sensors
current transformer
cable tie
connector
drilling machine
4. Final output
Actuate the hydraulic or pneumatic motor.
Actuate pneumatic or hydraulic valve.
Take real time reading from sensor.
Interlock all the possible faults that may occur
according the position of the sensor.
Show status of all the sensors and reading on
the hmi & that can also be changed.
All the work should be done in automatic as
well as manual mode.
Alarms are provided to indicate any error during
process
Change the values of any specific variable
according to the needs of customer so as to get
desired output.
5. PLC
A programmable logic controller, PLC, or programmable controller is a
digital computer used for automation of typically industrial
electromechanical processes, such as control of machinery on factory
assembly lines. PLCs are used in many machines, in many industries. PLCs
are designed for multiple arrangements of digital and analog inputs and
outputs, extended temperature ranges, immunity to electrical noise, and
resistance to vibration and impact. Programs to control machine operation
are typically stored in battery-backed-up or non-volatile memory. A PLC is an
example of a "hard" real-time system since output results must be produced
in response to input conditions within a limited time, otherwise unintended
operation will result.
6. The main difference from other computers is that PLCs are armored for severe
conditions (such as dust, moisture, heat, cold), and have the facility for
extensive input/output (I/O) arrangements. These connect the PLC to
sensors and actuators. PLCs read limit switches, analog process variables
(such as temperature and pressure), and the positions of complex
positioning systems. Some use machine vision. On the actuator side, PLCs
operate electric motors, pneumatic or hydraulic cylinders, magnetic relays,
solenoids, or analog outputs. The input/output arrangements may be built
into a simple PLC, or the PLC may have external I/O modules attached to a
computer network that plugs into the PLC.
PLCs have built-in communications ports, usually 9-pin RS-232, but
optionally Ethernet. Other options include various field buses such as
DeviceNet. Other communications protocols that may be used are listed in
the List of automation protocols. Most modern PLCs can communicate
over a network to some other system, such as a computer running a SCADA
(Supervisory Control And Data Acquisition) system or web browser. PLCs
used in larger I/O systems may have peer-to-peer (P2P) communication
between processors. This allows separate parts of a complex process to have
individual control while allowing the subsystems to co-ordinate over the
communication link. These communication links are also often used for
HMI devices such as keypads or PC-type workstations.
7. Hmi
The user interface, in the industrial design field of human–machine interaction, is
the space where interactions between humans and machines occur. The goal of
this interaction is to allow effective operation and control of the machine from
the human end, whilst the machine simultaneously feeds back information
that aids the operators' decision making process. Examples of this broad
concept of user interfaces include the interactive aspects of computer operating
systems, hand tools, heavy machinery operator controls, and process controls.
The design considerations applicable when creating user interfaces are related
to or involve such disciplines as psychology.
Generally, the goal of user interface design is to produce a user interface
which makes it easy (self explanatory), efficient, and enjoyable (user
friendly) to operate a machine in the way which produces the desired
result. This generally means that the operator needs to provide minimal
input to achieve the desired output, and also that the machine minimizes
undesired outputs to the human.
8. A physical connection that is available such as a Ethernet cable, or a RS-485
connection, along with the adequate ports on both hmi as well as plc. A
common protocol that can exist on the selected physical connection. Protocol
drivers that will bind the communication interface to the protocol. This is the
first part and is basic requirements for the data exchange. The second part is
what is exchanged between the PLC and the HMI. When you program the PLC,
you use registers in the CPU to control the process, signal alarm states and
collect the system status. This is part of the basis of the PLC program. When
you develop the HMI program, in each screen you create graphic interfaces that
reflect and send commands to the PLC program through the configured
protocol so that every input/output field, alarm display, status icon you
generate is linked to a tag, linked to an address of a register in the PLC.
So when you write a value in an input field you created to change the set point
of a PID loop, you transfer this value to the address specified (in the tag
definition) in the PLC program. When the PID output value changes in the
PLC, the HMI receives the value to display it in the output field you have
generated in the active field.
So basically the HMI prepares a list of tags it needs to write to the PLC tag
addresses, and values it has to read in the CPU memory every time it becomes
active, using the tag addresses configured in both PLC and HMI programs to
connect the two.
Communication of hmi with plc
9. Electrical drive vfd
Whenever the term electric motor or generator is used, we
tend to think that the speed of rotation of these machines
are totally controlled only by the applied voltage and
frequency of the source current. But the speed of rotation
of an electrical machine can be controlled precisely also
by implementing the concept of drive. The main
advantage of this concept is, the motion control is easily
optimized with the help of drive. In very simple words,
the systems which controls the motion of the electrical
machines, are known as electrical drives. A typical drive
system is assembled with a electric motor (may be
several) and a sophisticated control system that controls
the rotation of the motor shaft. Now a days, this control
can be be done easily with the help of software. So, the
controlling becomes more and more accurate and this
concept of drive also provides the ease of use. This drive
system is widely used in large number of industrial and
domestic applications like factories, transportation
systems, textile mills, fans, pumps, motors, robots etc.
Drives are employed as prime movers for diesel or petrol
engines, gas or steam turbines, hydraulic motors and
electric motors. Modbus connection is done for drives
with plc
10.
11. Mcb(current limiter)
There are two arrangement of operation of miniature
circuit breaker. One due to thermal effect of over
current and other due to electromagnetic effect of
over current. The thermal operation of miniature
circuit breaker is achieved with a bimetallic strip
whenever continuous over current flows through
MCB, the bimetallic strip is heated and deflects by
bending. This deflection of bimetallic strip releases
mechanical latch. As this mechanical latch is
attached with operating mechanism, it causes to
open the miniature circuit breaker contacts. But
during short circuit condition, sudden rising of
current, causes electromechanical displacement of
plunger associated with tripping coil or solenoid of
MCB due to the mmf generation in the coil. The
plunger strikes the trip lever causing immediate
release of latch mechanism consequently open the
circuit breaker contacts. Also with the manual
release of lever there is release of latch and hence
the circuit is breaked.
12. Comparision b/w mcb and fuse
It automatically switches off the electrical circuit during abnormal condition
of the network means in over load condition as well as faulty condition.
The fuse does not sense but miniature circuit breaker does it in more
reliable way. MCB is much more sensitive to over current than fuse. as the
switch operating knob comes at its off position during tripping, the faulty
zone of the electrical circuit can easily be identified. But in case of fuse,
fuse wire should be checked by opening fuse grip or cutout from fuse base,
for confirming the blow of fuse wire. Quick restoration of supply can not
be possible in case of fuse as because fuses have to be rewirable or replaced
for restoring the supply. But in the case of MCB, quick restoration is
possible by just switching on operation.
13. Rotary switch
A rotary switch is a switch operated by allowing
rotation to control different circuit functions.
To do this a Rotary switch consists of a
spindle or "rotor" that has a contact arm or
"spoke" that projects from its surface like a
cam. It also has an array of terminals,
arranged in a circle around the rotor, where
each terminal can serve as a contact for the
"spoke". In this way any one of a number of
different electrical circuits can be connected
to the rotor.
The benefit of a rotary switch is that they are
layered to allow use of multiple poles, where
each layer is equivalent to one pole. In most
case, rotary switches have a detent
mechanism so it "clicks" from one active
position to another rather than stalls in an
intermediate position. Because of these
attributes, rotary switches can provide greater
pole and throw capabilities than a simple
switches.
14. Contactor with overload
A contactor is an electrically controlled switch
used for switching an electrical power circuit,
similar to a relay except with higher current
ratings. A contactor is controlled by a circuit
which has a much lower power level than the
switched circuit.
Contactors come in many forms with varying
capacities and features. Unlike a circuit
breaker, a contactor is not intended to
interrupt a short circuit current. Contactors
range from those having a breaking current of
several amperes to thousands of amperes and
24 V DC to many kilovolts. The physical size of
contactors ranges from a device small enough
to pick up with one hand, to large devices
approximately a meter (yard) on a side.
15. star delta connection
Star Delta Transformations allow us to convert impedances connected
together from one type of connection to another. Star delta starter is used
to reduce the starting current drawn by the motor. Start the motor in STAR
and then, when the motor has gained sufficient speed, change its
connections to DELTA to allow the motor to run at its full speed and
torque from then on. The motor starts as star connected, ie, voltage
reduced by root(3), current reduced by root(3) and power reduced by 3.
After the motor starts, it is switched to delta connection and runs normally.
Star to delta change is done with the help of plc where timer is being
predefined to take the motor to it’s desired speed and it will switch from
star to delta. This signal is provided at the coil excitation.
16. Push buttons
A push-button (also spelled pushbutton) or simply button is a simple switch
mechanism for controlling some aspect of a machine or a process. Buttons
are typically made out of hard material, usually plastic or metal. The
surface is usually flat or shaped to accommodate the human finger or
hand, so as to be easily depressed or pushed. Buttons are most often biased
switches, though even many un-biased buttons (due to their physical
nature) require a spring to return to their un-pushed state. Different
people use different terms for the "pushing" of the button, such as press,
depress, mash, hit, and punch
17. Why push button preferred over toggle button
?
Push buttons are preferred over any other button’s like toggle button because
toggle button tends to hold the signal permanently until it’s state is being
changed manually. On the other hand while using push button the signal
is actively passed just until the button is pressed otherwise the signal
doesn't passes through it and it act as off state. But the signal can be
electrically hold with the help of contactor. So the add-on advantage of
using push button is that even though signal is for short span of time it can
be electrically hold and hence can state of the signal electrically which is
not possible in the case of toggle button.
18. How to hold the signal from push button
A signal from push button can be hold with the help of contactor. In
contactor the coil operated is to be operated to activate the contactor. It
produces no and nc signals which can be further used for signaling. Here
two wires are taken one through the push button(w1) and another one
directly to the contactor(w2). w1 is connected coil which excites the
contactor for a while until it is pressed. W2 is connected to no point of the
contactor. Now another wire is connected from nc point of contactor to the
coil excitation along with w1 point. So the signal get’s hold. Now if the cut
off the supply from w2 then the contactor is off. So again we have to press
push button to hold the signal.
19. Relay
A relay is an electrically operated switch. Many relays use an electromagnet to
mechanically operate a switch, but other operating principles are also used,
such as solid-state relays. Relays are used where it is necessary to control a
circuit by a low-power signal (with complete electrical isolation between
control and controlled circuits), or where several circuits must be controlled by
one signal.. Relays were used extensively in telephone exchanges and early
computers to perform logical operations. A type of relay that can handle the
high power required to directly control an electric motor or other loads is called
a contactor. Solid-state relays control power circuits with no moving parts,
instead using a semiconductor device to perform switching. Relays with
calibrated operating characteristics and sometimes multiple operating coils are
used to protect electrical circuits from overload or faults; in modern electric
power systems these functions are performed by digital instruments still called
"protective relays".
20. Current transformer
A current transformer (CT) is used for measurement of alternating electric
current. Current transformers, together with voltage (or potential)
transformers (VT or PT), are known as instrument transformers. When
current in a circuit is too high to apply directly to measuring instruments, a
current transformer produces a reduced current accurately proportional to
the current in the circuit, which can be conveniently connected to
measuring and recording instruments. A current transformer isolates the
measuring instruments from what may be very high voltage in the
monitored circuit. A wire carrying current is made to wrap around it to so
as to give current reading in current transformer.
21. Terminal
A terminal is the point at which a conductor from an electrical component,
device or network comes to an end and provides a point of connection to
external circuits. A terminal may simply be the end of a wire or it may be
fitted with a connector or fastener. It is used to either make different
further connection of same voltage with the help of short-link or
used for further connection.
22. Ryb strip
Ryb strip are used for the main power supply connection’s for the whole
panel. Further distribution of supply is done through this only. The main
purpose of using this ryb strip is that if we want to move the panel
somewhere else then inspite of removing whole connection just the
connection through this strip need’s to be changed which are very easy to
open.
23. Sensor
proximity sensor
capacitive type
Capacitive sensors are used for non-contact detection of metallic objects &
nonmetallic objects (liquid, plastic, wooden materials and so on).
Capacitive proximity sensors use the variation of capacitance between the
sensor and the object being detected. When the object is at a preset
distance from the sensitive side of the sensor, an electronic circuit inside
the sensor begins to oscillate. The rise or fall of such oscillation is
identified by a threshold circuit that drives an amplifier for the operation
of an external load. A screw placed on the backside of the sensor allows
regulation of the operating distance. This sensitivity regulation is useful in
applications, such as detection of full containers and non-detection of
empty containers.
24. reed switch
The reed switch is an electrical switch operated by an applied magnetic field.
It consists of a pair of contacts on ferrous metal reeds in a hermetically
sealed glass envelope. The contacts may be normally open, closing when a
magnetic field is present, or normally closed and opening when a magnetic
field is applied. The switch may be actuated by a coil, making a reed relay,
or by bringing a magnet near to the switch. Once the magnet is pulled
away from the switch, the reed switch will go back to its original position.
A magnetic field (from an electromagnet or a permanent magnet) will
cause the reeds to come together, thus completing an electrical circuit. The
stiffness of the reeds causes them to separate, and open the circuit, when
the magnetic field ceases
25. Position sensors are basically sensors for measuring the distance travelled by
the body starting from its reference position. How far the body has moved
from its reference or initial position is sensed by the position sensors and
often the output is given as a fed back to the control system which takes
the appropriate action. Motion of the body can be rectilinear or
curvilinear; accordingly, position sensors are called linear position sensors
or angular position sensors.
With the use of lever type position sensor placed at fixed position and nut
placed on the shaft of the servo motor we can get the desired position
sensor. The three nut’s are placed at different position which can be
adjusted according to our need. Hence sense can be done for different
position’s,
Position sensor
31. Valve
Direction control solenoid operated valve
A valve is a device that regulates the flow of fluid (gases, liquids, fluidized
solids, or slurries) by opening and closing or partially obstructing passage
ways 1. A 5/2 way directional valve from the name itself has 5 ports equally
spaced and 2 flow positions. It can be use to isolate
and simultaneously bypass a passage way for the fluid which for example
should retract or extend a double acting cylinder. There are variety of ways
to have this valve actuated. A solenoid valve is commonly used, a lever can
be manually twist or pinch to actuate the valve, an internal or external
hydraulic or pneumatic pilot to move the shaft inside, sometimes with a
spring return on the other end so it will go back to its original position
when pressure is gone, or a combination of any of the mention above.
32. Conclusion
Electrical Panels are required in every automation industry for the local
control of the final product to be operated. With the help of electrical
panel we can change the specifications of parameters required to be
changed in the final product. The academic program has supported me
a lot with the basic knowledge of each component. It helped me to be
familiar with the things that are actually implemented in the real time
system. Mainly the implementation part of those things can be seen
with this training period. Training period supported to bridge the gap
between industrial approach toward the things and the classical
approach that we use during our study period. How small ideas are
turned into project. It also gets gesture of what the industry demand
from us when we will be at their place. So academic program
complemented the training period so as to fulfill the industrial
demand.
