Hydraulics - Festo Didactic

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HydraulicsVocational and further training with Festo Didactic

Hydraulics training packages

System description .4Equipment setsHydraulics .6Electrohydraulics .10Measurement and control .16Proportional hydraulics .18Closed-loop hydraulics.22Mobile hydraulics.24SoftwareDesigning/Simulating with FluidSIM .34Components and accessoriesDirectional valves .36Pressure control valves .38Flow control valves/Stop valves .40Hosing, distributing/Additional components .42Drives .44Sensor technology/Measurement technology .46Power packs .48Control electronics/Electronic control .50Power supply/Order means .52TrainingsHydraulics/Electrohydraulics .54Proportional hydraulics .56Mobile hydraulics.573

Hydraulics training packages System descriptionHydraulics training packagesTailored training in industrial and mobile hydraulicsModular for flexible expansionFesto Didactic’s training packagesare modular in structure. For example, you could start with the basiclevel of electrohydraulics and thenmove onto the advanced level. Or areyou more interested in electropneumatics? The choice is yours. You’dlike to explore a particular specialised topic? All equipment set components can also be ordered separately, so you can turn your own ideasinto reality.4www.festo-didactic.comPosition it – clamp it – done!With the Quick-Fix mounting system, you can mount all componentseasily and securely on the profileplate or on the profile column of aLearnline workstation. The electricalunits are clamped into the ER frameand sequenced individually. The supports and the electrical units are thesame for both hydraulics and pneumatics – a single investment, withdouble the functionality.Everything where you want it –systematic storageMost equipment sets are suppliedwith an equipment tray or drawer insert in a Systainer. This equipmenttray fits in the drawers of the workstations. The large pictogram on thecomponents, designed in accordancewith the latest standards, providesclear instructions for connecting thecomponents and ensures short preparation and follow-up times. Whendismantling circuits, you can quicklyand easily locate where the component goes in the equipment tray.Connect it – power!Hydraulic power is supplied by thetool-free connection of low-leakagecouplings – the latest generation inhigh-grade stainless steel. The coupling is self-sealing when uncoupled.During the low-friction coupling procedure, only the front surface is coated with oil, which saves resources, iseasy on the environment, and reduces contamination.

Hydraulics training packages System descriptionDidactic plusThe workbooks accompanying thetraining packages contain projectoriented exercises of increasing complexity. There are also positionalsketches, illustrations, videos, animations and cross-sectional drawings, which explain how things lookin the real world. For a complete andexpert treatment of the topic of hydraulics, the training also covers basic physics, technical calculations,safety, efficiency, analytical faultfinding and professional documentation.Practical basic and further trainingusing industrial components provides the confidence to apply the acquired knowledge in the workplace.The components are specially selected for the exercises in the workbook.Note: nearly all hydraulic and electrical connections are located on theeasily accessible upper side of thecomponents.Your choice of training environmentUser-friendly training environmentsfor specific topic areas:– Self-study phases with the trainingprograms– Designing and documentation withFluidSIM – Practical implementation with thetraining packages and the exercises in the workbooks– Functional testing and optimisationwith measurement technology andFluidLab Quality not quantity!Bigger is not necessarily better.Volumetric flow rates and pressuresshould be chosen with care and inco-ordination with the system as awhole. This applies especially to hydraulic training systems. High forces and cylinder speeds not only increase the danger for the user, butalso require a larger hydraulic powerpack with higher power consumption. So our offer is: as large as necessary and as small as possible,without compromising on teachingeffectiveness.New technologies –new skills neededModern measurement and diagnostic technology and cartridge valvesare among the international trends inhydraulics. So you’ll find those technologies in our learning systems aswell. Benefit from the compact, integrated design, the low weight, easeof handling, and easy-to-read symbol system.Mobile hydraulicsThe new training packages for mobile hydraulics systematically andinformatively explore complex topicsand systems, such as work hydraulics, hydrostatic steering and drivesystems for the agricultural, forestryand construction vehicle sectors andwarehouse and municipal vehicles.www.festo-didactic.com5

Hydraulics training packages Equipment sets HydraulicsEquipment set TP 501 – Basic LevelBasic training in hydraulicsThe classic reissuedPure convenienceTraining contentThe solid basis for practical basicand further education. Training package TP 501 contains only purely hydraulic control systems.– Easy and exact switching of handlever valves– Simple and precise setting of theflow and pressure valves thanks tothe ergonomic handwheels and thefine resolution– Tool-free, single-hand operationwith quick action mounting systemQuick-Fix – Easy and secure plugging andreleasing of the new, low-leakage,self-sealing quick connection couplingsPower packs and components:– Design, function and most important characteristics of a hydraulicpower unit– Design and function of pressurerelief valves, cylinders and directional control valves– Design and function of the nonreturn valve, one-way flow controlvalve and piloted non-return valve– Design and function of flow control valvesThe number and version of the components are specifically adapted tothe projects in the workbook. This isa cost-effective way of achieving theimportant training objectives.TP 501, Basic Level is suitable for basic training in hydraulic control technology and imparts knowledge of thebasic physical principles of hydraulics, as well as the function and useof hydraulic components.6www.festo-didactic.comThe training package is delivered inpractical trays, packaged in a Systainer. The trays, in turn, fit exactlyinto the drawers in Learnline workstations.Measurements and calculations:– Recording and interpreting thecharacteristic curve of a hydraulic pump– Measuring the volume flow of ahydraulic control system– Recording the characteristic curveof a pressure-relief valve– Identifying and calculating times,pressures and forces during advancing and retracting of a cylinder– Recording the characteristic curveof a flow control valve– Calculating performance ratioswhen using 4/3-way valves withdifferent mid-positionsHydraulic circuits:– Commissioning hydraulic circuitssafely– Using the flow control valve in theinflow and outflow and adjustingthe drive speed– Difference between a flow controlvalve and one-way flow controlvalve in hydraulic control systems– Design and mode of operation of adifferential circuit– Effect of the piston surfaces onpressures, forces, speeds andtravel times– Proper use of piloted non-returnvalves– Circuits with different types ofcounter pressure– Operating cylinders with varyingloads

Hydraulics training packages Equipment sets Hydraulics573035Complete equipment set TP 501 in Systainer1234567891010111213141516The most important components at a glance:1 1x Pressure relief valve5443352 1x 2-way flow control valve5443383 1x One-way flow control valve1528434 1x Non-return valve, delockable5443395 1x Non-return valve, 0,6 MPa opening pressure5486186 1x 4/2-way hand lever valve, spring return5443427 1x 4/3-way hand lever valve, relieving mid-position (AB- T), detenting5443448 1x 4/3-way hand lever valve, closed mid-position, detenting5443439 1x Shut-off valve15284410 1x Differential cylinder 16/10/200 with cover57274611 1x Weight, 9 kg for cylinder15297212 1x Hydraulic motor15285813 1x T-distributor15284714 2x 4-way distributor with pressure gauge15939515 3x Pressure gauge15284116 1x Flow sensor567191Necessary accessories, also order:7x Hose line with quick release couplings, 600 mm1529603x Hose line with quick release couplings, 1000 mm1529702x Hose line with quick release couplings, 1500 mmMultimeter159386571832Aluminium profile plate InternetHydraulic power pack Pages 48 – 49Protective cover for weight Page 45Power supply unit for mounting frame Page 52The media on offer forTP 501HydraulicsBasic levelWorkbookTP 501The workbook contains:– Sample solutions– Training notes– Multimedia CD-ROM withphotos and videos of industrialapplications and circuit diagrams– Worksheets for studentsCD-ROM N551141ES551145FR551146BFesto Didactic551141 ENTraining course documentsThe basic circuits for hydraulics arepresented in 17 exercises. The symbols used in the circuit diagrams areaccording to DIN/ISO 1219. In orderto carry out the exercises, studentsrequire the equipment set for TP 501Hydraulics, Basic Level.Supplementary media– Designing and simulating withFluidSIM – Measuring and controlling withFluidLab – Digital learning programHydraulics/Electrohydraulics– Textbook Hydraulics – Basic Level– Hydraulics poster setwww.festo-didactic.com7

Hydraulics training packages Equipment sets HydraulicsEquipment set TP 502 – Advanced LevelHydraulics for advanced studentsThe new advanced levelHydraulics plus!Training contentThe training package TP 502 buildson the material covered in trainingpackage TP 501 – Basic Level, andadds 15 new projects to it.The new components provide addedtraining value and relevant projecttasks form the basis for advancedtraining in fundamental principles.The course expands students’ knowledge about the basic physical principles of hydraulics and the functionand use of further hydraulic components.The training package is delivered inpractical trays, packaged in a Systainer. These trays, in turn, fit exactlyinto the drawers in Learnline workstations.Power packs and components:– Design and function of ahydraulic motor– Setting the direction and speed ofrotation of a hydraulic motor– Design, function and use of a flowdivider– Using a hydraulic reservoir as avolume and pressure accumulator– Design, function and use of apressure regulator– Specifying the cylinder pressure– Difference between pressure-reliefvalves and pressure regulatorsIn order to carry out the projects,users require the components andthe necessary accessories fromequipment set TP 501.Measurements and calculations:– Calculating performance ratios ofhydraulic circuits from measuredvalues– Calculating forces on the cylinder– Creating procedure descriptions8www.festo-didactic.comHydraulic circuits:– Implementing bypass circuits– Ensuring synchronised forward andreturn strokes– Getting to know the bypass circuit– Getting to know the rapid traversefeed circuit– Advancing and retracting of acylinder after the pump from thereservoir is switched off– Use of a hydraulic reservoir for arapid traverse circuit– Getting to know the rectifier circuit– Configuration and description ofa sequence control with two cylinders– Getting to know the pressure sequence and pressure stage circuit– Getting to know the fuse protectionfor tensile loads

Hydraulics training packages Equipment sets Hydraulics573036Complete equipment set TP 502 in the Systainer123456777/8The most important components at a glance:1 1x Pressure relief valve, compensated5672372 1x 3-way pressure reducing valve5443373 1x Flow dividing valve5443404 1x 2/2-way stem actuated valve, convertible5443535 3x Non-return valve, 0,6 MPa opening pressure5486186 1x Diaphragm accumulator with shut-off block1528597 1x Differential cylinder 16/10/200 with cover5727468 1x Mounting kit for cylinders5443719 5x T-distributor152847Necessary accessories, also order:7x Hose line with quick release couplings, 600 mm1529604x Hose line with quick release couplings, 1000 mm1529702x Hose line with quick release couplings, 1500 mm159386Safety laboratory cables Page 52Multimeter571832Aluminium profile plate InternetHydraulic power pack Pages 48 – 49Protective cover for weight Page 459Power supply unit for mounting frame Page 52The media on offer forTP 502HydraulicsAdvanced levelWorkbookTP 502The workbook contains:– Sample solutions– Training notes– Multimedia CD-ROM withphotos and videos of industrialapplications and circuit diagrams– Worksheets for studentsCD-ROM N551147ES551148FR551149BFesto Didactic551147 ENTraining course documentsThe tasks explain further hydrauliccircuits. The equipment set of package TP 501 – Hydraulics Basic Leveland TP 502 – Advanced Level equipment set are needed to carry out thetasks.Supplementary media– Designing and simulating withFluidSIM – Measuring and controlling withFluidLab – Digital learning programHydraulics/Electrohydraulics– Textbook Hydraulics – Basic Level– Hydraulics poster setwww.festo-didactic.com9

Hydraulics training packages Equipment sets ElectrohydraulicsEquipment set TP 601 – Basic LevelBasic training in electrohydraulicsNew edition of electrohydraulics!Training contentTP 601 is a logical further development of electrohydraulics for training and further education. Theequipment set contains only electrohydraulic circuits and control systems.Power packs and components:– Design, mode of operation andareas of application of 2/2, 3/2,4/2 and 4/3-way solenoid valves,as well as 4/2-way double solenoid valves– Design and mode of operation ofelectrical pushbuttons, switchesand limit switches– Design and mode of operation ofa relay– Knowing and accounting for thecontact load capacity of electricalsignal transmitters– Selecting and using hydraulic andelectrical components according toeconomic criteria– Design and mode of operation of apressure switch– Knowing different ways of sensinga cylinder’s end position and selecting the right oneThe number and version of the components are specifically adapted tothe projects in the workbook. This isa cost-effective way of teaching theimportant training objectives.This equipment set provides students with knowledge about the basic physical principles of electricalengineering and electrohydraulics,as well as how electrohydraulic andcontrol technology components function and are used.10www.festo-didactic.comHydraulic circuits:– Commissioning hydraulic circuitssafely– Explaining and designing directand indirect actuation– Creating and using a sequencetable– Explaining and designing signalstorage in the hydraulic powersection– Selecting solenoid valves according to the technical control requirements– Using and designing basic logicfunctions– Explaining and designing anelectric latching circuit with adominant switch-off signal– Designing and arranging pressuredependent control systems– Knowing simple operating modesand accounting for them in the circuit– Electrically and mechanicallylocking of signals in a relay control system– Expanding existing control systemsand adjusting the documentation accordingly Implementing sequence control with two cylinders– Getting to know and creating a procedure description as GRAFCET andas a function diagram– Analysing circuits and carrying outsystematic fault finding and errorelimination with restartMeasurements and calculations:– Measuring and calculating the flowin an electrohydraulic installation– Calculating electrical characteristic values

Hydraulics training packages Equipment sets Electrohydraulics573037Complete equipment set TP 601 in the Systainer123456789101010/11121314151617181920The most important components at a glance:1 1x Pressure relief valve5443352 1x 2-way flow control valve5443383 1x One-way flow control valve1528434 1x Non-return valve, 0,6 MPa opening pressure5486185 1x 4/2-way solenoid valve, spring return5443466 1x 4/3-way solenoid valve, closed mid-position5443477 1x 4/2-way double solenoid valve, detenting5443528 1x Shut-off valve1528449 1x Weight, 9 kg for cylinder15297210 2x Differential cylinder 16/10/200 with cover57274611 1x Mounting kit for cylinders54437112 2x T-distributor15284713 2x 4-way distributor with pressure gauge15939514 2x Pressure gauge15284115 1x Pressure switch, electronic54861216 2x Relay, three-fold16224117 1x Signal input, electrical16224218 1x Limit switch, electrical, left-actuated18332219 1x Limit switch, electrical, right-actuated18334520 2x Proximity sensor, electronic548589Necessary accessories, also order:7x Hose line with quick release couplings, 600 mm1529602x Hose line with quick release couplings, 1000 mm1529704x Hose line with quick release couplings, 1500 mm159386Safety laboratory cables Page 52Multimeter571832Aluminium profile plate InternetHydraulic power pack Pages 48 – 49Protective cover for weight Page 45Tabletop power supply unit InternetPower supply unit for mounting frame Page 52The media on offer forTP 601ElectrohydraulicsBasic LevelWorkbookTP 601The workbook contains:– Sample solutions– Training notes– Multimedia CD-ROM withphotos and videos of industrialapplications and circuit diagrams– Worksheets for studentsCD-ROM 1A1A1Z11V1ABPT1M1124 V20Z10V1131214K1S11411A1K11M1A20V111214 .2212224313234414244Festo Didactic551150 ENTraining course documentsThe basic electric circuits for hydraulic control technology are presentedin 15 exercises. In order to carry outthe exercises, students require theequipment set of TP 601 Electrohydraulics, Basic Level.Supplementary media– Designing and simulating withFluidSIM – Measuring and controlling withFluidLab – Digital learning programHydraulics/Electrohydraulics– Textbook Electrohydraulics –Basic Level– Hydraulics poster setwww.festo-didactic.com11

Hydraulics training packages Equipment sets ElectrohydraulicsSupplementary equipment setsControllers for electrohydraulics1423Supplementary equipment setControlling using FluidSIM /EasyPort USBWith this package, the FluidSIM software can be used to controltraining packages. FluidSIM controls via EasyPort USB and processesthe inputs and outputs connected tothe universal connection unit according to their programming, e.g. using the digital module contained inFluidSIM .5The Controlling using FluidSIM package contains everything youneed to control training packages TP201 and TP 601. FluidSIM Pneumatics is required for TP 201 and FluidSIM Hydraulics for TP 601. A set ofbrief instructions provides information on the individual steps.The sample solutions are includedon a data storage medium as FluidSIM CT programs.Complete supplementary equipment set in the Systainer556270The most important components at a glance:1 1x Brief instructions for FluidSIM, DE/EN/FR/ES5562672 1x EasyPort USB5486873 1x EasyPort adapter for profile plate5498064 1x Universal connection unit, digital (SysLink)1622315 1x I/O data cable with SysLink connectors (IEEE 488) at both ends, 2.5 m34031Prerequisite:Equipment set TP 601 – Basic level Pages 10 – 11FluidSIM Hydraulics (from version 4) Pages 34 – 351423Supplementary equipment setControlling usingLOGO! EduTrainer Compact TP/LOGO! Soft ComfortThe quick, uncomplicated and inexpensive introduction to logical signalprocessing. With its extensive basicand special control technology functions, LOGO! replaces a variety ofconventional switchgears and control devices.The LOGO! EduTrainer Compact TPpackage contains everything youneed to control training packagesTP 201 and TP 601. A set of brief instructions provides information onthe individual steps. Programming iscarried out using the programmingsoftware LOGO! Soft Comfort.The sample solutions are includedon a data storage medium as LOGO!Soft Comfort programs.Complete supplementary equipment set in the Systainer556271The most important components at a glance:1 1x Brief instructions for LOGO!, DE/EN/FR/ES5562682 1x LOGO! EduTrainer Compact TP5352503 1x LOGO! Soft Comfort, DE/EN/FR/ES/IT/PT5265054 1x LOGO! Programming cable526504Prerequisite:Equipment set TP 601 – Basic Level Pages 10 – 11Necessary accessories, also order:Aluminium profile plate InternetHydraulic power pack Pages 48 – 49Power supply unit for mounting frame Page 52Safety laboratory cables Page 5212www.festo-didactic.com

Hydraulics training packages Equipment sets ElectrohydraulicsSupplementary equipment setsElectrohydraulicsSupplementary equipment set from Hydraulics, Basic level TP 501 toElectrohydraulics, Basic level TP 601123/4567888/9101112For training aims see Electrohydraulics, Basic level TP 601 equipment set.Complete supplementary equipment set TP 501 – TP 601573039The most important components at a glance:1 2x Relay, three-fold1622412 1x Signal input, electrical1622423 1x Limit switch, electrical, left-actuated1833224 1x Limit switch, electrical, right-actuated1833455 1x 4/2-way double solenoid valve, detenting5443526 1x 4/2-way solenoid valve, spring return5443467 1x 4/3-way solenoid valve, closed mid-position5443478 1x Differential cylinder 16/10/200 with cover5727469 1x Mounting kit for cylinders54437110 1x Pressure switch, electronic54861211 2x Proximity sensor, electronic54858912 1x T-distributor152847Supplementary equipment set from Hydraulics, Basic level TP 501 andAdvanced level TP 502 to Electrohydraulics, Basic level TP 601For training aims see Electrohydraulics, Basic level TP 601 equipment set.Complete supplementary equipment set TP 501 and TP 502 – TP 601573040The most important components at a glance:1 2x Relay, three-fold1622412 1x Signal input, electrical1622423 1x Limit switch, electrical, left-actuated1833224 1x Limit switch, electrical, right-actuated1833455 1x 4/2-way double solenoid valve, detenting5443526 1x 4/2-way solenoid valve, spring return5443467 1x 4/3-way solenoid valve, closed mid-position54434710 1x Pressure switch, electronic54861211 2x Proximity sensor, electronic548589www.festo-didactic.com13

Hydraulics training packages Equipment sets ElectrohydraulicsEquipment set TP 602 – Advanced LevelElectrohydraulics for advanced studentsThe new advanced levelTraining contentThe training package TP 602 buildsdirectly on the material covered inbasic principles package TP 601, andadds more in-depth projects to it.Power packs and components:– Design and mode of operation ofdifferent proximity sensors– Function and possible applicationsof a time relay with switch-on andswitch-off delay– Design and use of an electricalpredetermining counterIt provides students with advancedknowledge about the basic physical principles of electrical engineering and electrohydraulics, as wellas how electrohydraulic and controltechnology components function andare used.In order to carry out the projects, users require the components and thenecessary accessories from TP 601.The number and version of the components are specifically adapted tothe projects in the workbook. Thismakes it possible to achieve manyimportant training objectives at littlecost.14www.festo-didactic.comLearning objectives for hydrauliccircuits:– Selecting proximity sensors according to the technical control requirements– Expanding electrohydraulic controlsystems and adjusting the documentation– Designing and arranging path- andpressure-dependent sequencecontrols– Identifying signal overlaps in asequence control and taking theappropriate action– Designing and arranging sequencecontrol as a standing sequencer– Using memory to implement anemergency operation– Implementing control systems withthe operating modes single cycleand continuous cycle– Querying time in electrohydrauliccontrol systems– Getting to know and using furtherlogical connections– Designing and arranging pressuresequence control– Knowing safety-related conditionsthat could be needed for a drive– Designing and arranging safetyfunctions with a predefined motionsequence for a control system– Implementing control systems withthe operating modes inching andaligning– Systematically identifying andeliminating errors in complex electrohydraulic control systems– Creating sequence control as adisplacement-step diagram– Representing procedure descriptions with GRAFCETHydraulics plus!The training package is delivered inpractical trays, packaged in a Systainer. The trays fit into the drawers in Learnline workstations. Thenew components, with added training value and relevant project tasks,form the basis for advanced trainingin fundamental principles.

Hydraulics training packages Equipment sets Electrohydraulics573038Complete equipment set TP 602 in the Systainer1234567891011The most important components at a glance:1 1x Time relay, two-fold1622432 2x Relay, three-fold1622413 1x Preset counter, electrical, incrementing1623554 1x Diaphragm accumulator with shut-off block1528595 1x Hydraulic motor1528586 1x 4/3-way solenoid valve, relieving mid-position (AB- T)5443487 1x Proximity sensor, inductive, M125486438 1x Emergency stop pushbutton, electrical1833479 1x T-distributor15284710 1x Non-return valve, delockable54433911 1x Pressure relief valve, compensated567237Necessary accessories, also order:8x Hose line with quick release couplings, 600 mm1529604x Hose line with quick release couplings, 1000 mm1529702x Hose line with quick release couplings, 1500 mm159386Safety laboratory cables Page 52Multimeter571832Aluminium profile plate InternetHydraulic power pack Pages 48 – 49Protective cover for weight Page 45Tabletop power supply unit InternetPower supply unit for mounting frame Page 52The strong blended learning rangefor TP 602ElectrohydraulicsAdvanced LevelWorkbookTP 602The workbook contains:– Sample solutions– Training notes– Multimedia CD-ROM withphotos and videos of industrialapplications and circuit diagrams– Worksheets for studentsCD-ROM included24 12K5DEA1K10A2A2A2A21A1 2A1 2A1–1A1–.A2.0VFesto Didactic551153 ENTraining course documentsThe basic practical circuits in electrohydraulics are presented in 12exercises. In order to carry out theexercises, students require theequipment set of TP 601 Electrohydraulics, Basic Level and AdvancedLevel TP 602.Supplementary media– Designing and simulating withFluidSIM – Measuring and controlling withFluidLab – Digital learning programHydraulics/Electrohydraulics– Textbook: Basic level – Electrohydraulics– Hydraulics poster setwww.festo-didactic.com15

Hydraulics training packages Equipment sets Measurement and controlEquipment set TP 610 – Advanced levelMeasurement and control in Hydraulics with FluidLab -HFit for tomorrow?The equipment set for TP 610 expands the training content of TP 501and TP 601 to include the topic ofhydraulics measurement and control. The material covered rangesfrom recording simple characteristiccurves of individual hydraulic valvesthrough to the basic principles ofcylinder control. In addition, awareness is raised in a clear and strikingmanner about the effective use ofhydraulic energy, e.g. with resistanceexperiments.New features of FluidLab -H includethe measurement experiments forproportional technology with recording characteristic curves and applications such as pressure stages andrapid traverse feed circuits, as wellas control technology with position,sequence and pressure control.Exercises for the measurement andanalysis of system and control behaviour point to a future in whichdiagnostics, preventative maintenance and saving energy are becoming more and more important.16www.festo-didactic.comSomething extra specialIn order to the complete the exercises, sensors (e.g. pressure, flowand position) are connected to theinputs and control signals are transmitted to the EasyPort USB outputs.The FluidLab -H software included inthe scope of delivery interprets andvisualises the signals. Analogue values are displayed as measurementcurves.Each exercise includes notes on itsimplementation, with positionalsketches and block circuit diagrams.Students are guided step by stepthrough the experiments. Measuredresults are then interpreted, compared with sample solution

Hydraulics training packages System description Hydraulics training packages Tailored training in industrial and mobile hydraulics 4 Modular for flexible expansion Festo Didactic’s training packages are modular in structure. For exam-ple, you could start with the basic level of electr