Module 1 Lecture 2: Components & Applications of Automation Systems PDF

MT308 Industrial Automation Module 1 Lecture 2: Basic Concept of Automation Terminology & Applications Mechatronics Engineering Department Faculty of Engineering Sana’a University  Module 1 - Lecture 2: Basic Concept of Aut...

MT308 Industrial Automation Module 1 Lecture 2: Basic Concept of Automation Terminology & Applications Mechatronics Engineering Department Faculty of Engineering Sana’a University  Module 1 - Lecture 2: Basic Concept of Automation Terminology & Applications Sections: ❑ Basic Concept of Automation Terminology ❑ Automation System in an application ©2008 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 2  Objectives: Explain the basic concept of automation terminology Explain the positioning concept of automation. Describe the automation system in an application ©2008 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 3  Industrial Robot Defined ❑An automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place of mobile for use in industrial automation applications (ISO 8373) ▪ Why industrial robots are important: ▪ Robots can substitute for humans in hazardous work environments ▪ Consistency and accuracy not attainable by humans ▪ Can be reprogrammed ▪ Robots are controlled by computers and can therefore be connected to other computer systems  Basic Concept of Automation Terminology ❑ The robot’s anatomy affects its capabilities and the tasks for which it is best suited. There is a set of basic terminology and concepts common to all robots. These terms follow with brief explanations of each. 1. Joints and Links: Each joint provides a “degree-of-freedom” Most robots possess five or six degrees-of-freedom Joints are the movable couplings between them. Joints or axes found in the manipulator (robotic arm) as shown in Figure 1.1. Robots are often classified according to the total number of axes they possess. A robot’s joint, or axis consists of two types: 1. Major axis: comprising the base, shoulder and elbow and 2. Minor axis: comprising wrist pitch, wrist roll and wrist yaw. Links are the solid structural members of a robot, connected to each joint are two links (Figure 1.2), an input link and an output link. Links are the rigid components of the robot manipulator. The purpose of the joint is to provide controlled relative movement between the input link and the output link.  Basic Concept of Automation Terminology Figure 2.: Diagram of robot construction showing how a robot is made up of a series of joint-link combinations Robot manipulator - a series of joint- Figure 1: A Cincinatti Milacron T3 robot link combinations Robot manipulator consists of two sections: Body-and-arm – for positioning objects in the robot's work volume Wrist assembly – for orienting objects 6  Basic Concept of Automation Terminology ❑ Five types of mechanical joints for robots may be classified: two types that provide translational motion and three types that provide rotary motion. Joint Description Schematic Linear joint Type L joint; the relative movement between the input link and the output link is a translational sliding (telescoping) motion, motion with the axes of the two links parallel. Orthogonal Type O joint; the relative movement between joint the input link and the output link is a translational sliding motion, but the output link is perpendicular to the input link. Rotational Type R joint; this provides rotational relative joint motion, with the axis of rotation perpendicular to the axes of the input and output links. 7  Basic Concept of Automation Terminology ❑ Five types of mechanical joints for robots may be classified. Joint Description Schematic Twisting Type T joint; this provides rotary motion, but joint the axis of rotation is parallel to the axes of the two links. Revolving Type V joint; the axis of the input link is joint parallel to the axis of rotation of the joint, and the axis of the output link is perpendicular to the axis of rotation ❑ Each of these joint types has a range over which it can be moved. The range for a translational joint is usually less than a meter, but for large gantry robots, the range may be several meters. The three types of rotary joints may have a range as small as a few degrees or as large as several complete revolutions. 8  Basic Concept of Automation Terminology Robot Body-and-Arm Configurations ▪ Five common body-and-arm configurations for industrial robots: 1. Articulated robot (aka jointed-arm robot) 2. Polar configuration 3. Selective Compliance Arm for Robotic General configuration of a human arm Assembly (SCARA) 4. Cartesian coordinate robot Consists of a sliding arm (L joint) actuated relative 5. Delta robot to the body, which can rotate about both a ▪ Function of body-and-arm assembly is to vertical axis (T joint) and position an end effector (e.g., gripper, tool) horizontal axis (R joint) in space 9  Basic Concept of Automation Terminology Robot Body-and-Arm Configurations Delta Robot Cartesian ▪ Consists of three arms attached to an Coordinate Robot overhead base ▪ SCARA = Selectively Compliant ▪ Each arm consists of two rotational Assembly Robot Arm ▪ Consists of three sliding joints, joints (type R), the first of which is ▪ Similar to jointed-arm robot except powered and the second is two of which are orthogonal that vertical axes are used for unpowered shoulder and elbow joints to be ▪ Other names include gantry ▪ All three arms are connected to a compliant in horizontal direction for robot, rectilinear robot, and x-y- small platform below, to which an vertical insertion tasks z robot end effector is attached 10  Basic Concept of Automation Terminology Wrist Configurations ▪ Wrist assembly is attached to end-of-arm ▪ End effector is attached to wrist assembly ▪ Function of wrist assembly is to orient end effector ▪ Body-and-arm determines global position of end effector Typical wrist assembly has ▪ Two or three degrees of freedom: two or three degrees-of- ▪ Roll: using a T joint to accomplish rotation about the freedom (shown is a three robot’s arm axis; degree-of freedom wrist) Joint Notation Scheme ▪ Pitch: which involves up-and-down rotation, typically using an R joint; and ▪ Uses the joint symbols (L, O, R, T, V) to ▪ Yaw: which involves right-and-left rotation, also designate joint types used to construct robot accomplished by means of an R-joint. manipulator ▪ A two-axis wrist typically includes only roll and pitch joints ▪ Separates body-and-arm assembly from wrist (T and R joints). assembly using a colon (:) ▪ Example: TLR : TR 11  Basic Concept of Automation Terminology Joint Notations for Five Arm-and-Body Configurations Configuration Notation Work Volume Articulated TRR Partial sphere Polar TRL Partial sphere SCARA VRO Cylindrical Cartesian coordinate OOO Rectangular solid Delta 3(RRu) Hemisphere 12  Basic Concept of Automation Terminology 2. Degree of freedom (DOF) : ❑ Each joint on the robot introduces a degree of freedom. Each dof can be a slider, rotary, or other type of actuator. ❑ Robots typically have 5 or 6 degrees of freedom. 3 of the degrees of freedom allow positioning in 3D space, while the other 2 or 3 are used for orientation of the end effector. 6 degrees of freedom are enough to allow the robot to reach all positions and orientations in 3D space. 5 dof requires a restriction to 2D space, or else it limits orientations. 5 dof Figure 3 : Each joint represents a degree of robots are commonly used for handling tools such as freedom; there are 22 joints and thus 22 degree of freedom in the human hand arc welders. ©2008 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 13  Basic Concept of Automation Terminology 2. Degree of freedom (DOF). ❑ From the Figure 4, we can see that the robot has 5 degrees of freedom, which means we can have it move in five independent ways. The five different movements are created in five different joints as described below: 1. Base Joint: This joint allows movement of 350° rotational motion. 2. Shoulder Joint: This joint allows movement of 120° rotational motion. 3. Elbow Joint: This joint allows movement of 135° rotational motion. 4. Wrist Joint: This joint allows movement of 340° rotational motion. 5. Gripper: This joint allows movement of 2 linear motions Figure 4 : OWI-007 robotic (open and close actions).. arm trainer (Copyright OWI 14 Robots)  Basic Concept of Automation Terminology 2. Orientation Axes: 3. Position Axes: ❑ Basically, if the tool is held at a fixed position, the orientation determines which ❑ The tool, regardless of orientation, can be moved to a direction it can be pointed in. Roll, pitch and yaw are the common orientation axes number of positions in space. Various robot used. ❑ Looking at the Figure 4, it will be obvious that the tool can be positioned at any geometries are suited to different work geometries. orientation in space. Imagine sitting in a plane: The definition of an object's location in 3-D space, If the plane rolls you will turn upside or downside. The pitch changes for usually defined by a 3-D coordinate system using X, takeoff and landing; and when flying in a crosswind the plane will yaw. Y, and Z coordinates. Part of a robot can move to a spot within its work envelope, using devices that tell it exactly where it is. 4. Tool Centre Point (TCP) ❑ The tool center point is located either on the robot, or the tool. Typically the TCP is used when referring to the robots position, as well as the focal point of the tool. (e.g. the TCP could be at the tip of a welding torch). ❑ The TCP can be specified in Cartesian, cylindrical, spherical, etc. coordinates depending on the robot. As tools are changed Figure 4 : Orientation Axes we will often reprogram the robot for the TCP. Tool midpoint is the reference point of tools controlled by the robot. 15  Basic Concept of Automation Terminology 4. Tool Centre Point (TCP): ❑ Work envelope is the volume/area where the robotic arm can perform task/work (Figure 6 & Figure 7). The space in which a robot can operate is its work envelope, which encloses its workspace. ❑ Workspace of the robot defines positions and orientations that it can achieve to accomplish a task. ❑ The work envelope also includes the volume of space the robot itself Figure 5 : Tool Centre occupies as it moves. Point (TCP) ❑ This envelope is defined by the types of joints, their range of movement and the lengths of the links that connect them. ❑ The physical size of this envelope and the loads on the robot within this 5. Work Volume/workspace envelope are of primary consideration in the design of the mechanical structure of a robot. Defined as the three-dimensional space within which the robot can manipulate the end of its wrist ▪ Also known as work envelope ▪ Determined by: ▪ Number and types of joints Figure 6 : Mitsubishi RV- M1’s work envelope ▪ Ranges of joints ▪ Physical sizes of links  Basic Concept of Automation Terminology 5. Work envelope/workspace 6. Speed ❑ Speed is the rate of movement from point to point done by robots under the control of the program. It’s refers either to the maximum velocity that is achievable by the TCP, or by individual joints. ❑ This number is not accurate in most robots, and will vary over the workspace as the geometry of the robot changes (and hence the dynamic effects). The number will often reflect the maximum safest speed possible. Some robots allow the maximum rated speed (100%) to be Figure 7 : Work passed, but it should be done with great care. envelope/workspace ❑ Maximum joint velocity (angular or linear) is not an independent value. For longer motions it is often limited by servomotor bus voltage or maximum allowable motor speed. ❑ For manipulators with high accelerations, even short point-to-point motions may be velocity limited. For low-acceleration robots, only gross motions will be velocity limited. ❑ Typical peak end-effector speeds can range up to 20m/s for large robots.  Basic Concept of Automation Terminology 7. Payload: 8. Repeatability: ❑ The payload indicates the maximum mass the ❑ A high repeatability robot will be able to repeat robot can lift before either failure of the robots, the task with the right repeatedly without error. or dramatic loss of accuracy. ❑ The robot mechanism will have some natural ❑ It is possible to exceed the maximum payload, variance in it. This means that when the robot and still have the robot operate, but this is not is repeatedly instructed to return to the same advised. point, it will not always stop at the same ❑ When the robot is accelerating fast, the payload position. Repeatability is considered to be +/-3 times the standard deviation of the position, or should be less than the maximum mass. This is where 99.5% of all repeatability measurements affected by the ability to firmly grip the part, as fall. This figure will vary over the workspace, well as the robot structure, and the actuators. especially near the boundaries of the ❑ The end of arm tooling should be considered workspace, but manufacturers will give a part of the payload. Maximum payload is single value in specifications. specified in kilograms.  Basic Concept of Automation Terminology 9. Accuracy: ❑ The degree of ability that can be made by a robotic arm to move to a certain point in the work cell as we enter the coordinates in the off-line programming station. This is determined by the resolution of the workspace. ❑ If the robot is commanded to travel to a point in space, it will often be off by some amount, the maximum distance should be considered the accuracy. This is an effect of a control system that is not necessarily continuous (Figure 8). Figure 8 : Accuracy is determined by the resolution of the workspace  Basic Concept of Automation Terminology 10. Settling Time: and a direct drive servo motor is used to drive the joint, ❑ The settling time is the time required for the robot with a resolution of 0.5 degrees, then the control to be within a given distance from the final resolution is about 0.5 degrees (the worst case can be 0.5+0.01). position. The time-instant when the actual output ❑ Capability of robot's positioning system to divide the converges to the desired output is known as the motion range of each joint into closely spaced settling time. During a movement, the robot points. moves fast, but as the robot approaches the final 12. Coordinates : position is slows down, and slowly approaches. ❑ The robot can move, therefore it is necessary to 11. Control Resolution define positions. Note that coordinates are a combination of both the position of the origin and ❑ This is the smallest change that can be measured orientation of the axes. Points are programmed in the by the feedback sensors, or caused by the cells identified job position by using the values of the actuators, whichever is larger. coordinates x, y and z of the tools midpoint and ❑ If a rotary joint has an encoder that measures extension angles at the wrist axis robot arm is pitch, every 0.01 degree of rotation, roll and yaw.  Basic Concept of Automation Terminology World Coordinate System Origin and axes of robot manipulator are defined relative to the robot base  Basic Concept of Automation Terminology Tool Coordinate System ❑ In a tool-coordinate system, Figure 8.13(b), the alignment of the axis system is defined relative to the orientation of the wrist faceplate (to which the end effector is attached). ❑ In this way, the programmer can orient the tool in a desired way and then control the robot to make linear moves in directions parallel or perpendicular to the tool. ❑ The world- and tool-coordinate systems are useful only if the robot has the capacity to move its wrist end in a straight line motion, parallel to one of the axes of the coordinate system. Straight line Alignment of the axis system is defined relative to motion is quite natural for a Cartesian coordinate the orientation of the wrist faceplate (to which the robot (LOO configuration) but unnatural for end effector is attached) robots with any combination of rotational  Basic Concept of Automation Terminology 1. World coordinates 12. Coordinates : 3. Joint coordinates 2. Tool coordinates  End Effectors ❑ The special tooling for a robot that enables it to perform a specific task ▪ Two types: ▪ Grippers – to grasp and manipulate objects (e.g., parts) during work cycle ▪ Tools – to perform a process, e.g., spot welding, spray painting ▪ Advances in Mechanical Grippers: Dual grippers Interchangeable fingers Sensory feedback ▪ To sense presence of object ▪ To apply a specified force on the object Multiple fingered gripper (similar to human hand) A two-finger mechanical Standard gripper products to reduce the amount of custom design required gripper for grasping rotational parts 24  Robot Accuracy and Repeatability ❑ Three terms used to define precision in robotics, similar to numerical control precision: 1. Control resolution - capability of robot's positioning system to divide the motion range of each joint into closely spaced points 2. Accuracy – capability of robot's positioning system to position the robot's wrist at a desired location in the work space, given the limits of the robot's control resolution 3. Repeatability – capability of robot's positioning system to position the wrist at a previously taught point in the work space ©2008 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 25  Positioning Concept of Automation 1. Accuracy and Repeatability : ❑ The accuracy and repeatability are functions of, i. Resolution- the use of digital systems, and other factors mean that only a limited number of positions are available. Thus user input coordinates are often adjusted to the nearest discrete position. ii. Kinematic modeling error - the kinematic model of the robot does not exactly match the robot. As a result the calculations of required joint angles contain a small error. iii. Calibration errors - The position determined during calibration may be off slightly, resulting in an error in calculated position. iv. Random errors - problems arise as the robot operates. For example, friction, structural bending, thermal expansion, backlash/slip in transmissions, etc. can cause variations in position.  Positioning Concept of Automation Accuracy : ❑ “How close does the robot get to the desired point”. This measures the distance between the specified position, and the actual position of the robot end effector. Accuracy is more important when performing off-line programming, because absolute coordinates are used. Repeatability : ❑ “How close will the robot be to the same position as the same move made before”. It is a measure of the error or variability when repeatedly reaching for a single position. This is the result of random errors only. Repeatability is often smaller than accuracy. ❑ Resolution is based on a limited number of points that the robot can be commanded to reach for; these are shown here as black dots. These points are typically separated by a millimeter or less, depending on the type of robot. This is further complicated by the fact that the user might ask for a position such as 456.4-mm, and the system can only move to the nearest millimeter, 456-mm, this is the accuracy error of 0.4-mm.  Positioning Concept of Automation Figure 9: In a perfect mechanical situation the accuracy and control resolution would be determined as below, Figure 11: Random errors will prevent the robot from returning to the exact same location each time and this can be shown with a probability distribution about each point. Figure 10: Kinematic and calibration errors basically shift the points in the workspace resulting in an error ‘e’. Typically vendor specifications assume that calibration and modeling errors are zero.  Positioning Concept of Automation Figure 12: If the distribution is normal, the limits for repeatability are typically chosen as ±3 standard deviations ‘s’. We can look at distributions for each specified position for the robot end effector in relationship to other point distributions. This will give us overall accuracy, and spatial resolution.. Positioning Concept of Automation  Positioning Concept of Automation Control Resolution ❑ Spatial resolution: is the smallest increment of movement into which the robot can divide its work volume. Spatial resolution depends on two factors: 1. The systems control resolution, and 2. The robots mechanical inaccuracies ❑ It is easiest to conceptualize these factors in terms of a robot with 1 degree of freedom. ❑ Control resolution: is the controller’s ability to divide the total range of movement for the particular joint into individual increments that can be addressed in the controller. The increments are sometimes referred to as “addressable parts”. Control resolution: is determined by the robot’s position control system and its feedback measurement system. The ability to divide the joint range into increments depends on the bit storage capacity in the control memory. The number of separate, identifiable increments (addressable points) for a particular axis is:  Positioning Concept of Automation Control Resolution ❑ A robot with 8 bit control resolution can divide a motion range into 256 discrete positions. The control resolution is: 𝑟𝑎𝑛𝑔𝑒 𝑜𝑓 𝑚𝑜𝑡𝑖𝑜𝑛/256. The increments are almost always uniform and equal. If mechanical inaccuracies are negligible, "Accuracy = Control Resolution/2" ❑ The second limit on control resolution is the bit storage capacity of the controller. If B = the number of bits in the bit storage register devoted to a particular joint, then the number of addressable points in that joint's range of motion is given by: 2𝐵 ❑ The control resolution is therefore defined as the distance between adjacent addressable points. This electro-mechanical control resolution may be denoted CR. ❑ Owing to the wide variety of joints used by robots, and their individual mechanical characteristics, it is not possible to characterize each joint in detail. There is, however, a mechanical limit on the capacity to divide the range of each joint-link system into addressable points, and that limit is given by 𝐶𝑅2 , which is the bit storage capacity of the controller. This is given by:  Positioning Concept of Automation Control Resolution ❑ where 𝐶𝑅2 is the control resolution determined by the robot controller; R is the range of the joint-link combination, expressed in linear or angular units; and B is the number of bits in the bit storage register devoted to a particular joint. The maximum of 𝐶𝑅2 gives the control resolution. ❑ For repeatability, the mechanical errors that make the robot’s end-of-wrist return to slightly different locations than the programmed point are to blame. For a single joint-link mechanism: 𝑅𝑒 = ±3𝜎 where Re is repeatability; and σ is the standard deviation of the error distribution. For accuracy, we have: where CR is control resolution; and σ is the standard deviation of the error distribution. ❑ Robot precision is determined by three important considerations; these are: control resolution, repeatability, and accuracy. Positioning Concept of Automation  Positioning Concept of Automation Payload: ❑ The payload is always specified as a maximum value, this can be before failure, or more commonly, before serious performance loss. ❑ Static considerations: i. Gravity effects cause downward deflection of the arm and support systems drive gears and belts often have noticeable amounts of slack (backlash) that cause positioning errors ii. Joint play (windup) - when long rotary members are used in a drive system and twist under load iii. Thermal effects - temperature changes lead to dimensional changes in the manipulator ❑ Dynamic considerations: I. Acceleration effects - inertial forces can lead to deflection in structural members. These are normally only problems when a robot is moving very fast, or when a continuous path following is essential. (But, of course, during the design of a robot these factors must be carefully examined) Positioning Concept of Automation Positioning Concept of Automation Positioning Concept of Automation Positioning Concept of Automation Positioning Concept of Automation  Automation System in an Application ▪ Single Station Manned Cells: Most industrial production operations are based on the use of single station manned and automated cells. Let us expand the list here: A CNC machining center. The machine executes a part program for each part. The parts are identical. A worker is required to be at the machine at the end of each program execution to unload the part just completed and load a raw work part onto the machine table. A CNC turning center. The parts are identical & machine executes a part program for each part.. A worker is required to unload finished parts and place them in a tote pan and then load raw parts from another tote pan. This is similar to the preceding machining center, but a different machining process is performed. Same as the preceding except the parts are not identical. → the machine operator must call the appropriate part program and load it into the CNC control unit for each consecutive work part. A duster of two CNC turning centers, each producing the same part but operating independently from its own machine control unit. A single worker attends to the loading and unloading of both machines. The part programs are long enough relative to the load/unload portion of the work cycle that this can be accomplished without forced machine idle time. A plastic injection molding machine on semi.automatic cycle, with a worker present to remove the molding, sprue, and runner system when the mold opens each molding cycle. Parts are placed in a box by the worker. Another worker must periodically exchange the tote box and resupply molding compound to the machine. A stamping press that punches and forms sheet metal parts from flat blanks in a stack near the press. A worker is required to load the blank into the press, actuate the press, and then remove the stamping each cycle. Completed stampings are stored in four-wheel trucks that have been especially designed for the part.  Automation System in an Application ▪ Single Station Automated Cells: Following are examples of single station Figure 12 automated cells. We have taken each of the preceding examples:: A CNC machining center with parts carousel and automatic pallet changer, as in the layout of Figure 12. The parts are identical, and the machining cycle is controlled by a part program. Each part is held on a pallet fixture. The machine cuts the parts one-by-one, when all of the parts in the carousel have been machined; a worker removes the finished pieces from the carousel and loads starting work parts. Loading and unloading of the carousel can be performed while the machine is operating.. A CNC turning center with parts storage tray and robot. The robot is equipped with a dual gripper to unload the completed piece and load a starting work part from the parts storage tray each cycle. The parts storage tray can hold a certain quantity of parts. In effect, this is the same case as the CNC machining center, just a different machining process.  Automation System in an Application ▪ CNC Machining and Turning Centers: A numerically controlled horizontal machining center: are usually designed with features to reduce non- productive time. These features include the following: 1. Automatic tool-changing 2. Automatic work part positioning 3. Automatic pallet changer ▪ Automation Storage/Retrieval System: is a storage system that performs storage and retrieval operations with speed and accuracy under a defined degree of automation. ▪ Different levels of automation may be applied. At one extreme, the AS/RS is completely automated. This can include a full complement of totally automated, computer-controlled storage functions that are integrated into overall factory or warehouse operations. At the other extreme it may use human workers to control equipment and perform storage/retrieval transactions. Using modular components, available from AS/RS vendors, the AS/RS system is custom-designed to fit the requirements of the plant in which it is installed.  Automation System in an Application ▪ Automation Machining with Robot ▪ Automation Loading/ Unloading System ▪ Automation CNC Machining System ▪ Automation Machining and Inspection System  ©2008 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. No portion of this material may be reproduced, in any form or by any means, without permission in writing from the publisher. For the exclusive use of adopters of the book Automation, Production Systems, and Computer-Integrated Manufacturing, Third Edition, by Mikell P. Groover. 45  Process vs. Discrete Industries ▪ Process industries ▪ Production operations are performed on amounts of materials ▪ Liquids, gases, powders, etc. ▪ Discrete manufacturing industries ▪ Production operations are performed on quantities of materials ▪ Parts, product units  Process Industries & Discrete Manufacturing Industries ▪ Having examined the basic elements and contents of automation, we can now look in more detail at industrial control systems. These labels are also useful here to describe the sorts of automation that occurs in each type of industry. Table 2 details the two industry types, and their respective automation uses for each level of automation  Process Industries & Discrete Manufacturing Industries ▪ Significant variations exist at lower levels owing to the differences in devices and equipment used in the two industries. At higher levels, the control of the unit, or the control of machinery provides the basis for the differences between levels two and three. Levels four and five are, in comparison, fairly similar across both process industries and discrete manufacturing industries. Figure 13: Process and discrete industries respectively