pumpkin fruit fly, water melon fruit fly, cucumber fruit fly
Operational mechanisms of feed mill
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OPERATIONAL MECHANISMS OF FEED MILL & SOFTWARE TO
HANDLE FEED MILL OPERATIONS
Feed Mill:
Feed mill is a Production Building which produces feed for animals and Poultry.
Feed is produced for a number of animals such as livestock, poultry and ruminants,
domestic animals, and fish. Feed mills manufacture pellets, crumbles or mash and
these products are shipped in bagged form. Feed milling facilities may be dedicated to
producing feed for either single or multiple species.
Introduction
The process of manufacturing animal feed is a means whereby raw materials of
widely ranging physical, chemical and nutritional composition can be converted into a
homogenous mixture suitable for producing a desired nutritional response in the
animal to which the mixture is fed. The process is basically a physical one and chemical
changes are few. It should be remembered however that some raw materials will have
undergone extensive processing prior to inclusion into a mixed feed, for example,
extraction of oil from oilseeds by solvent or mechanical extraction, heat treatment of
soya beans or other beans to denature anti-nutritive factors, or the production of
fishmeal and meat meal.
The feed manufacturing process may be considered to be made up of several unit
operations which, in almost all circumstances, include the following:
Raw material selection & storage
Raw material weighing
Raw material grinding
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Mixing of dry ingredients and addition of liquids
Pelleting of mixed feed (optional)
Blended feed bagging, storage and dispatch
RAW MATERIAL SELECTION & STORAGE
The raw materials coming into a feed process area will have been requested by the
nutritionist as being necessary to meet the nutrient requirements of the diet to be
manufactured.
Laboratory testing of raw ingredients:
Hygrometer1 give result within 30 sec 14% normal, if 15% so 1% reduction in weight is
considered. More than 15% = rejected
1 A hygrometer is an instrument used for measuringthe moisture content in the specific grains.
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In order toensure a continuous supply of raw materials at the mill, when some may
only be seasonally available on the market, and to take advantage of price fluctuations,
some form of storage will be necessary.
Raw materials should arrive in good condition and in sacks which have not been used
for the storage of fertilizer, pesticides or chemicals.
Storage areas must be waterproof and well-ventilated, and provide protection
against infestation by insects and vermin which can quickly cause substantial losses in
weight. If materials are to be stored in bags they should be kept in a building having a
concrete floor. Theroof and walls need only to be lightly constructed provided that they
are pest and waterproof. The bags should be stacked a few inches above floor level.
Ingredients can be transported via:
• Bucket elevators
• Belt conveyors
• Paddle conveyors
• Drag chain conveyors.
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The most common type of conveyor in feed mills is the screw conveyor, because it offers
the potential for easy transporting of materials.
The two major materials of construction that are used for feed mills are:
• Concrete
• Steel
Concrete feed mills are used for large scale facilities. Steel feed mills are especially
common for smaller-scale facilities. A specific design
consideration for a given feed mill is the amount of space allocated to storage of bulk
ingredients.
Each silo has 7 monitoring sensors one at centre and other in circle around the centre and
sheets.
Capacity formula.
A= volume of cylinder B = volume of
cone
r = radius
H = height
If 22 kg maize in one cubic feet so, Volume of silo × 22 = total capacity of silo.
1 silo= 2500 tons of maize, wheat, rice tips.
Raw material weighing/Batching System:
The accurate weighing of raw materials according to the formulation for a given
ration is perhaps the most important unit operation involved in feed manufacture,
since no amount of mechanical processing can make up for any deficiencies in nutrients
𝑨 = 𝝅𝒓 𝟐
× 𝑯 B =
1.047 × 𝒓 𝟐
× H
A + B = Volume of silo
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which have been omitted from the mixture. The point at which weighing occurs in the
feed milling process will depend upon the design of the mill. Raw materials may be
selected from store, weighed and then subjected to grinding and mixing, or materials
may be pre-ground, then weighed and mixed.
Large bin-type weighers are often used for raw materials which have been pre-
ground or are free flowing and discharge readily from storage bins or silos. Bin-type
weighers may be mobile or stationary. Inline weighers which measure the quantity of
material flowing over a small electronic sensor and volumetric dischargers are also
available.
Bins capacities
Each bin consist of two parts,
Concrete part
Hopper ( steel made )
Volume of bin calculate by calculating and add the volume of concrete part and hopper
So,
Volume of concrete bin = L × W × H
= 10.5×10.5×25 = 2756 cubic feet
Volume of Rectangular shape hopper
L1 = 10.5
L2 = 3.33
B1 = 10.5
B2 = 1.66
567 cubic feet volume of hopper according to
formula
Total volume is 3324 cf
If 15 kg material in 1 cf then 50 tons capacity
Main scale is 3 ton 16 micro bins are installed above the main scale 1bin capacity is 500
bag.
In order to produce particular feed mixtures, appropriate quantities of specific
ingredients must be transferred out of storage and transported to the mixer. This is the
function of the batching system.
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For all major and minor ingredients, the equipment used to for this includes screw
conveyors which provide excellent proportioning control, and scale hoppers above the
mixer.
Bulk bag and hand dump stations are also frequently used to add ingredients to the feed
mixture.
The weighing of raw materials requires great care and inaccuracies must be kept to a
minimum. It should be noted that errors in the weighing of small quantities of raw
materials often have far greater influence on the growth performance of animals than
errors in the weighing of large quantities of material,
Raw material grinding
Prior to utilization in feed formulations, whole grain must be ground to reduce particle
size. Grinding before mixing more better than after batching.
Reasons:
Large fragments are reduced in size.
Some moisture is removed due to aeration.
Additives such as antioxidants may be blended.
All of these improve the ease of handling ingredients and their storability. The
grinding of ingredients generally improves feed digestibility, mixing
properties, palatability, and increases the bulk density of some ingredients.
In the sequence of unit operations involved in feed milling, raw material grinding
may occur before or after weighing. It is a process with high power requirements which
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is often noisy and dusty. The design of machine most commonly found in the feed.
Inside the grinding chamber, hammers, which may be fixed rigidly to the central shaft,
or more often swinging on steel pins, rotate at high speed. The impact of the raw
material on the hammers and the continual high-velocity impact of particle on particle
results in material breakdown until it is small enough in size to pass through a
perforated screen.
Grinding systems are generally located directly under whole grain storage bins.
Roller mills are gaining popularity because of their ability to produce coarse, uniform
particle size, with reduced noise levels and power consumption.
If ground material is conveyed pneumatically, the air and material are separated in
a cyclone2 . This simple device, which is similar to an inverted cone, causes air to swirl
around its walls depositing the ground material at the base of the cone while the air
exits at the top of the cyclone through a filter. Cyclones are normally only 95% efficient
at separating ground particles and air, and a cloth or other type of filter is necessary as
a dust barrier.
The moisture content of raw materials to be ground in a hammer mill should not
normally exceed13-14%.High-moisture feeds are plastic or malleable in character with
few planes of impact weakness and may clog a conventional hammer mill designed for
handling dry ingredients.
Mixing of dry ingredientsand addition of liquids
It is the job of the mixer to produce a homogenous blend of all the raw materials
desired in a formulation, such that at each feeding period each animal receives a
balanced mixture of nutrients
2 Cyclone is dustcollector.
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Mixing often improves feed palatability if one or more of the raw materials is unpalatable
to livestock
Concrete mixers
Small concrete mixers with electric or petrol engine drives are mobile low cost
machines suitable for the manufacture of mixtures of dry ingredients or mixtures of
wet feeds,
For larger-scale feed mixing however it is advisable and probably cheaper to use one
of the conventional feed mixers described below.
Conventional feed mixers
Two designs of mixers are most commonly found in the feed industry: the vertical (or
fountain) mixer and the horizontal (or U-trough) mixer.
Vertical mixers
. Raw materials may enter the mixer either at the top, from a cyclone or auger feed
from the grinder, or at the base of the screw at a sack tipping point. After mixing for a
pre-determined time, normally 10-15 minutes (although this time may be shorter in
some mixes), the mixture is discharged into a bag or conveyed by auger or bucket
elevator to a storage bin or pelleter.
Since many raw materials are dusty it is often desirable to include materials such as
molasses, oils and fats in the formulations to reduce dustiness as well as to provide a
source of nutrients. Vertical mixers, because of their slow-running action, are generally
less effective in distributing liquids throughout the mixture, and liquids tend to form
beadlets or balls coated with fine particle material, rather than produce a surface
coating on the solid material
Horizontal mixers
As the name suggests, horizontal mixers operate with a horizontally turning mixing
shaft, the mixer is suitable for blending up to 8% liquids into a dry mix and therefore
offers greater versatility if a wide range of rations are to be offered from one feed mill
unit. It is preferable that fats and molasses be warmed before addition to the raw
materials in the mixer and they should be added as the last ingredients.
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Conveyor mixers
Conveyor mixers are also available, particularly for farm use, and consist of a
trapezoid metal box in which mixing is effected by slats extending almost the full width
of the machine and which are carried on a pair of endless chains. Like the vertical mixer
this machine is limited in its ability to blend liquids thoroughly into the mixture.
Pelleting of mixed feed
Two pellet mills in SFM, 1 pellet mill produce 300bag/hr. (15 ton), 600 bag (poultry
feed)/hr. can be produce.
The use of pelleted feed is often popular with farmers because it is convenient to handle
and reduces dustiness. . Pellets also reduce feed losses during feeding, and may help to
maintain, or increase, feed intake under certain conditions. The heat generated during
pelleting can inactivate some pathogenic bacteria which may be present in raw materials.
However, pelleting increases the cost of feeds because the capital cost of pelleters is
relatively high compared to grinders or mixers, the energy requirement is high, and
additional care and skill is necessary for their maintenance and operation.
Pelleting involves the compression of a mixed feed through holes in a hardened steel
ring or plate (a die) by means of hardened steel rollers. The die forms the feed into
pencil-like extrusions which are cut by knives into pellets of desired length on leaving
the die.
Pelleters may also be divided into two further groups according to the pre-treatment
of mixed feed prior to compression or extrusion in the die head. Pelleters may be
considered as cold pelleters or conditioner pelleters.
=
= 450 × 391 × 0.9 × 1.732 / 22.5 × 1000 = 12.18kW/tons = 0.609kW/bag
Pellet Machine Efficiency
A × V × 1.732 × Power
Factor Tons / hr ×
1000
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Cold pelleters
In cold pelleting, mixed feed is fed directly from a bin or auger into the die head at
ambient (normal atmospheric) temperatures. Some water may be added, preferably in
the mixer if the meal is too dry to bring it to approximately 15-16% moisture, but there
is no heat treatment of the mixed meal before it enters the die.
Conditioner pelleters
The term 'cold pelleting' is something of a misnomer since a considerable amount of
heat is generated during the pelleting operation, but it serves todistinguish the process
from conditioner pelleting which is the usual process in industrial pelleters. During
conditioner pelleting, the mixed meal is directly pre-heated with dry steam. The steam
preheats or conditions the meal to the preferred temperature and moisture content for
pelleting according to the formulation of the mixture, for example, 65-121°C avg 80°C
and 15-25% moisture
Generally, the quality of pellets (that is, resistance to break-down after pelleting and
during handling) of a given mixture from a conditioner pelleter is marginally better
than that from a cold pelleter, but the conditioner pelleter requires a boiler and
associated water treatment plant to treat the feed water for the boiler.
Factors that Affect Steam Conditioning
Mash particle size,
Surface area increases geometrically as particle size decreases
Retention time
30 to 90 seconds for optimum pellet quality
5 to 20 seconds is more typical in the industry
Pick (Paddle) Angle
Retention time decreases as forward angle increases.
Shaft speed
Water Addition
Optimum conditioning at16-17.5%moisture, with 4-5%moisture added by the
conditioner
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Pellet quality
Pellets should have a desired degree of hardness, and should also show high resistance
to abrasion during handling and transport.
Pellet binders
Some mixtures of raw materials do not bind well together when pelleted and require
the addition of special binding agents. Molasses is often added at 2-5% to aid binding,
but other binders include bentonite clays and lignosulphonates, and are added at the
suppliers' recommended dosage levels, usually about 1-2%.
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Cooling & Stabilizing:
The Pellet Cooler is used for cooling hot feed pellets from 80o C to ambient
temperature. Cooling columns are on either side with central duct for conveying hot
air. Wire mesh separates pellets from air. Set of flaps regulate flow of cold air inside the
cooler. Thepellets while falling operate inside portion of the flaps and cold air is passed
through stock of pellets.
Basically three types of coolers used in the feed industry:
Vertical
Horizontal
Counter flow
Pellets are then cooled from 80°C to ambient.
Crumbling
Pellet Crumblier is an essential equipment for the preparation of crumbled pellet feed.
The pellets can then be diverted into the crumblier, if crumbles or granules are desired,
or they can by-pass it. This is used for breaking the pellets into crumbs required for
chicks which are 2-3 weeks old. Pellets are broken into pieces of the required size
between the two rolls of the crumblier situated below the cooler/drier exit. The gap
between the rolls can be adjusted to regulate the size of crumbs. The roller gap is
adjusted with a hand wheel mechanism.
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Sieve Grading:
Grading rotary sieve is made to grade and screen the pellets getting gone through
crushing in the large or medium-sized animal feed. It is also used to clean the initial
materials to process pellets. It is applicable for screening and classifying of mash or
pellet feed. It is also can be used for cleaning of raw materials. Large pellets and very
small particles with ground material are recycled through the pelleting machine.
Bagging / Packing:
Load Cell Type Bagging Machine
The Load Cell Type Bagging Machine or Bagging-Off-Weigher is an electronically
controlled bagging machine. It is a heavy-duty machine for the repeated and accurate
weighment in bags of products like pelleted or mashed feed, grains, sugar and cereals. It
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consists of a bin hopper, feeder with slow-speed and high-speed drives, a weighment chute
supported on load cells and a pneumatically operated bag clamp. The accuracy of the
machine is 0.2 %. When bag put at mouth of cell, clump took message to sliding gate open
for specific weight of feed dragging down in bag, as weight attained according to our input
to load cell. Load cell message to pneumatically controlled cylinders to close the gates. As
gate close clumps release and bag moves to sieving machine by belt conveyer. Here packing
complete and feed bag either store in store house or directly load to vehicle.
Automatic filling of feed bag This Portable bag closing machine is widely used in sewing
feed bags, rice bags, fertilizers bags and seed bags.
Load out:
• Feed bag packing 50 kg poultry feed , Wanda 37 kg / bag
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Dryer
Drying is the process that reduces grain moisture content to a safe level for storage, Proper
Drying will maintain grain quality and minimize losses.
Purposes of Drying
The purpose of drying is to reduce the moisture content of rough rice to a level safe for
storage. Drying of grain involves exposing grain to ambient air with low relative humidity
or to heated air. This will evaporate the moisture from the grain and then the drying air
will remove the moisture from the grain.
Types of dryer
Continuous flow dryer
Conventional Continuous Flow Dryer
Cross flow dryers
Counter flow dryers
Flash Dryer
The fluidized bed dryer consists of a
drying chamber with an air speed of
around 2.3 m/s, a bed thickness of 10
cm in which the grain is exposed to
the drying air for 10-15 minutes.
Capacities of commercial units range
from 1-10 t/h. A diesel burner or a
rice hull furnace is used as heat
source and a system for recycling 50-
70% of the drying air is provided to
improve energy efficiency.
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Cross flow dryers
Cross flow dryers are of simple design. In the drying zone the grain moves downwards
between two perforated metal sheets while the air moves horizontally through the grains
Parts of dryer
Perforated metal sheets 44 rings
Twoblur fans 75 hp motor of each
FD (forced) fan 50 hp motor
Heat exchanger
Rotary 3 hp motor
Steam header
Dryer panel
Conveyer and elevators
At top of the dryer material enter which we want to
decrease moisture. It has 12feet external diameter,
and internally 10 feet. it is made up 44 rings of
perforated sheet internal and external cylinder, each
ring contains 7 sheet, total height is of 70 feet. As
material enter spread in between the both sheets.
Capacity almost 30 tons / hr. FD fan installed some
height from the bottom, FD fan forced the air to heat
exchanger, in heat exchanger a lot of steam pipes net.
As air cross these pipes area warm up to 100-120
degree Celsius. In heat exchanger steam pressure 120
psi. When warm air enter in the shell of dryer two
blur installed at bottom of shell forced the hot air
towards top of dryer. This hot air cross from material
to dry the material, maximum temperature at top of
dryer, as moves downward temperature gradually deceases, in last five rings of dryer use to
decrease the temperature of material, and after completing the drying process when
required moisture attained material comes out through rotary. Rotary speed can be
adjusted according to moisture level of material, if more moisture than rotary speed slower
down for more exposure to hot air to material. Rotary speed can be vary from 10-60 Rev.
per Min. at 26 rev. rotary speed 10tons paddy dry per hour from moisture 20 to 12 %.
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Boiler
Boiler broadly classified into twocategories,
Water tube
Fire tube
Fire Tube Water Tube
Fire inside the tubes Water inside the tube
Less space required More
Less Expensive More
Easily moveable Not to move
Easy to clean Difficult to clean as no. of tubes more
and ‘D’ shape
More fuel required Less fuel
Single pass to 4 pass fire in tubes to
increase the fuel utilization
Single pass to 4 pass fire by bricks
dimensions
In Hi-Tech feed mill Unit 3 Sahiwal In Hi-Tech oil mill.
Boilers are classified as on the base of fuel also such as Gas, Diesel, wood, coal etc.
Fire tube boiler of 5 tons per hour capacity.
Capacity of boiler depends upon on the heating surface of the boiler
1350 feet square heating surface.
Wood use as fuel in In Hi-Tech feed mill Unit 3 Sahiwal, wood produce 4tons
steam per 1 ton of wood.
Maximum pressure of steam at boiler is 150psi, it is controlled by the safety
valve.
Water pH 8 and TDS 100 of water which is used to produce steam
Parts of boiler
Three main thing to run the boiler
1. FD (Forced) Fan; its function is forced the air into furnace (combustion chamber) to
stimulate the fire, its running motor is 5 hp.
2. ID (induced) Fan; it induced the air from main shell/ boiler to chimney, having
motor 40hp.
3. Water Feed Pump also call multistage centrifugal pump; it consist of stages/
impellers, function of impeller is to increase pressure. Its pressure 1.5 times more
than boiler inside pressure.
Other parts
Drying pipe; its function is to allow only steam to move out and filter the water
drops.
Rose pipe; it acts like a shower, prevent the water directly hitting on fire tubes
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Safety valve; It control the pressure up to 150psi, above its range that will open and
save the over pressure problems in the boiler.
Main hole; entry point for repairing purposes.
Air valves; toremove vaccum from the boiler when again start after some time
break.
Cyclone; to separate ash and dust, allow smoke to release out.
Below down valve; for water discharge from the boiler.
Water level gauge glass; to check water level.
Stop valve; tostop the steam
Steam Flow
From boiler to conditioner throughout steam line 4inch and insulated.
Distributer (Header) it get steam and distribute the steam to multiple lines, near to
boiler, dryer and next pellet sides.
Strainer: it is sieve type valve use tofiltrate the particles from the steam to protect
the seats of valve.
Steam Trap: it is use to separate the water from the steam
Pressure reducing valves: use to control the pressure in a constant way, use before
the conditioner to avoid the over conditioning problems.
At pellet side trapper valves separate the water this water comes back into boiler for
recycling by two inch pipe line.
RO (Reverse Osmoses) Plant
Sand filter; it can bear 20 psi pressure, it remove heavy sand particles
Bag filter; it filter the particles those pass out from the sand filter
Cartridge filter; seven in no. in series, these work to filter more fine particles at high
pressure
Pump; it takes water from cartridge filter to membranes
Membranes; two in no, these control the TDS, separate the TDS water and pure
water
Chemicals; Flocon 260, AQASIS 744 to control the TDS
PLC (programmable Logic Control)
This consists of a list of logic functions and instructions, which are successively
processed through a program.
Control System
This a customizable software and hardware package.
With a custom hardware and software solution you have the ability to monitor and
completely control a facility from a PC.
The operation of the PLC controller can be monitored and changed via the
keyboard/mouse and the recipes/alarming log etc.
The PLC graphically displays the information on a screen (touch screen or standard)
and allows the user to manipulate the data on the PLC (start/stop motors, view
outgoing batches etc.)
Some powerful features of the control system are,
This greatly reduces operational cost while increasing facility efficiency.
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Allows for quick and easy administration decisions
It is programmable to fit the customer’s needs
It is easily expandable to fit the customers growing and changing needs
This will control major, minor, and micro ingredients through one scale or several
scales along with control of liquid ingredients.
With the automatic batch mixing process the control package can control automatic
destination of the mixed product.
Control Systems development time reduced by up to 80%
It reduced overall costs of development, boost of productivity and dramatically
increased reliability.
Todesign input data we need following specifications
All inputs that are given to software program are in the form of a statement
Record of Inputs/Outputs that connected to PLCs
Records specifying lists of plant facilities of different variety controlled by the system
like motors, valves and their control parameters.
Records of Control Sequences, Control state machines, interlocking etc.
List of PLCs used, their types and configuration and memory map.
Currently, for auto generation purposes, design input data is stored in Excel
spreadsheets, but it can be provided in the form of Access data bases or SQL
databases.
The PLC program being developed, could be for any kind of industrial automation
application one can think of (e.g. process control, machine control, automated
production lines, oil refineries, water supply/treatment etc.)
Structure of a PLC Program
They consist of individual, separately defined programs sections which are executed
in sequence.
These programs sections are called blocks (input/output block, etc.)
The blocks are functionally independent.
Assigning a particular (technical) function to a specific block, which has clearly
defined and simple interfaces with other blocks
Blocks contain the program logic graphically represented.
Programming Languages
PLC programs can be constructed using various methods of representation. Some of
the common ones are, described below.
The Relay Ladder Logic (RLL) Diagram:
It is a visual and logical method of displaying the control logic which, based on the
inputs determine the outputs of the program.
The ladder is made up of a series of “rungs” of logical expressions expressed
graphically as series and parallel circuits of relay logic elements such as contacts,
timers etc.
Each rung consist of a set of inputs on the left end of the rung and a single output at
the right end of each.
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Inputs/Outputs:
The input operands refer to external physical signals of the controlled system, whose
values are acquired from the input signal modules
Internal Variable Operands or Flags
Their function is to save intermediate computational values of the program.
Timer:
These are special operands of a PLC, which represent a time delay relay in a relay
logic system.
It is possible to achieve time delays in the range of few milliseconds to few hours.
Counter:
Thecounting functions (C) operate as hardware. Thecounting range is from 0 to 999.
PLC program Cycle:
When Initialise the PLC then scanning starts then it read all inputs individually then
processed the PLC program memory, when match thePLC memory with the Software
stored memory then it update all out puts.
The time required by the microprocessor to complete one cycle is known as the scan
time. After all rungs have been tested, the PLC then starts over again with the first
rung. Of course the scan time for a particular processor is a function of the processor
speed, the number of rungs, and the complexity of each rung.
Motor Interlocking
Pelleting interlocking system
Rotary (Cyclone) Cyclone Screener Elevator Convayer
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Mixer to Pellet bins Interlocking
Crumblers Cooler
Rotary (below
pellet)
Pellets
Conditioner 1
then 2 then
feeder
Convayer(above
pellet bins)
Drum cleaner elevator convayers