- Technical documentation in industrial automation is key to the efficient design, assembly, safety, and maintenance of facilities.
- A complete project includes a report, electrical and pneumatic drawings, PLC I/O diagrams, operation and maintenance manuals, and quality and environmental appendices.
- Tools such as AutoCAD, CADeSIMU and ePLAN Electric allow you to create, structure and update complex documentation with standardized symbology.
- Training in technical documentation within the Higher Technician in Automation and Industrial Robotics cycle prepares the professional to manage real projects.
Documentation and manuals in industrial automation are not just a piece of paper to be filed away and forgotten. They are the foundation for a well-designed, error-free, and safe automated installation, ensuring it operates at peak performance for years to come. In any modern production line, from the initial project concept to the final maintenance report, everything relies on well-prepared technical documentation.
When we talk about industrial automation and robotics , we're talking about programmable logic controllers (PLCs) , communication networks, electrical panels, electropneumatic systems, robots, sensors, variable frequency drives, monitoring software, and much more. Coordinating all of this without clear documentation would be an impossible task. That's why, within the training of a higher-level technician in industrial automation and robotics, technical documentation is considered a key module and is covered in great depth, from the types of project documents to quality and environmental appendices.
Importance of technical documentation in industrial automation
In an automation project, technical documentation directly impacts the overall performance of the plant: downtime, ease of troubleshooting, speed of modifications or expansions, operator safety, and the ability to justify costs. A project may have excellent hardware and sophisticated software, but if the documentation is poor, time and money will ultimately be wasted, and risks will increase. The overall performance of the plant depends as much on the design as on the quality of the supporting documentation.
Experience in the sector has shown that complete and well-structured technical documentation significantly reduces errors during assembly, avoids ambiguous interpretations between departments (engineering, production, maintenance, purchasing), and makes it easier for any new technician to understand the installation without always having to rely on the person who installed it. This is especially critical in complex production lines involving electrical panels, automation systems, pneumatic systems, and collaborative robots.
Furthermore, in many industrial projects, documentation is a contractual requirement . The end client demands a minimum set of documents: a report, technical specifications, electrical and pneumatic diagrams, an operating manual, a maintenance manual , a spare parts list, certificates of conformity, etc. Incomplete or poorly prepared documentation can lead to delays in the acceptance of the installation, financial penalties, or the need to redo a large portion of the documentation at the end of the project.
In the educational field, specialized works on Technical Documentation for Industrial Automation and Robotics programs systematically outline how these documents should be prepared and organized. These references have become standard study and reference material in both vocational training centers and engineering departments because they organize concepts and standardize criteria for representation, symbology, and formats.
On the other hand, it's important to remember that technical documentation is also key to safety . Occupational health and safety regulations and machinery directives require manufacturers to provide clear user manuals, lockout/tagout procedures, up-to-date diagrams, and clearly visible warnings. Poor documentation can lead to unsafe operations, errors in electrical lockouts, or inappropriate interventions on automated systems.
Fundamental documents of an automation project
Within any industrial automation project, there is a set of basic documents considered essential for designing, assembling, programming, and maintaining the installation reliably. These documents follow a structure that is typically repeated in most engineering firms.
First, there is the project's technical report , which describes the automation objective, scope, initial situation, solutions adopted, main installation characteristics, and design criteria (applicable standards, safety levels, production requirements). This report serves as a general guide and reference for understanding the project as a whole.
Another key element is the technical specifications and bills of materials . These detail the selected equipment (PLCs, I/O modules, variable frequency drives, relays, disconnect switches, contactors, valves, cylinders, sensors, actuators, etc.), their main characteristics, manufacturers, and part numbers. These specifications are used for both purchasing and maintenance, as they allow for the quick location of the appropriate spare parts.
Electrical, electronic, and pneumatic schematics represent power, control, and communication systems. They include everything from the general power supply and protection diagrams to the details of each terminal block, each PLC I/O module, each wired sensor, and every element of the industrial network. Without these schematics, troubleshooting or modifying parts of the installation becomes a much slower and more error-prone task.
Along with the drawings, operational diagrams and functional documentation are prepared : flowcharts , sequence descriptions, signal timing diagrams, input/output tables, and comments on the control logic. This part is essential for PLC programmers and supervisory system operators, but also for maintenance personnel, who need to understand exactly what each program does and under what conditions it operates.
Finally, the set of documents for a project includes operation and maintenance manuals . The operation manual explains to the user how to use the installation: operating modes, manual maneuvers, start-up and shutdown procedures, and safety guidelines for daily use. It also covers inspection, cleaning, adjustments, replacement of wear components, as well as the management and diagnosis of common malfunctions.
Standard graphic representation rules and symbology
For any technician to correctly interpret documents, it is essential to follow standard graphic representation and symbology conventions . In industrial automation, international references such as the IEC 60617 series are used for electrical graphic symbols, in addition to specific standards for pneumatics, hydraulics, and the representation of control elements.
The consistent use of standardized electrical and electronic symbols ensures that a diagram can be understood by technicians from different companies and countries. Switches, contactors, relays, disconnectors, circuit breakers, residual current devices, transformers, variable frequency drives, and PLCs are represented with agreed-upon symbols, accompanied by clear designations (e.g., Q for switches, K for relays, F for fuses, etc.).
In the field of pneumatics and electropneumatics, specific symbols are also used for valves, cylinders, actuators, and auxiliary components . Diagrams of paths and positions, flow direction arrows, and actuation elements (electrical, manual, mechanical) are represented with standardized symbols that allow the circuit's behavior to be understood at a glance.
Another fundamental part of the graphical representation is the device designation code , which assigns each component a unique identifier (for example, -Q1, -K10, -M3, -B2). This code is repeated in drawings, bills of materials, and programming software, so that the relationship between the schematic, the physical equipment, and the variable in the PLC program can be easily traced.
Adhering to these graphic representation standards is not merely an aesthetic matter. It simplifies project review, reduces confusion, facilitates audits and certifications, and helps maintain consistency across different documents throughout the facility's lifecycle. Furthermore, many computer-aided design tools incorporate libraries of standardized symbols to ensure this consistency.
Creating graphic documentation with AutoCAD and using layers
In the creation of drawings for industrial automation, one of the most widely used programs is AutoCAD , especially for electrical schematics, floor plans, and assembly details. One of the keys to obtaining clear and manageable documentation is the intelligent use of layers , which allow information to be organized by element type.
A common practice is to separate power conductors, control lines, control signals, I/O references, and dimensions into independent layers . This allows you to show or hide groups of information as needed, simplifying the review process and preventing the drawing from becoming illegible due to too much simultaneous detail.
Layers are also used to differentiate existing and new elements in expansion or renovation projects. By varying the color, line thickness, or stroke type, it becomes easier to recognize which parts of the installation are being modified and which are being retained—something especially useful when working in operational plants where the entire system cannot be shut down at once.
Another important aspect is the creation of standardized blocks of symbols and boxes , which are reused in different projects. This practice unifies criteria, saves time, and ensures that the symbology used is always the same. In automation projects, these blocks typically include symbols for contacts, coils, terminal blocks, PLC terminals, I/O cards, protection relays, and junction boxes, among others.
In AutoCAD graphical documentation, attention is also paid to scale, text size, and drawing hierarchy . General drawings show the overall view (for example, the single-line diagram of the power supply), while detail drawings focus on specific panels, floor areas, or automation subassemblies. All of this is organized in a drawing index that facilitates navigation through the entire documentation.
Technical drawings of electrical installations and automated systems
Beyond generic CAD, in industrial automation, specific technical drawings of electrical installations and automated systems are of particular importance , requiring a very precise structure and content. This includes power diagrams as well as those for control and communication systems.
Power diagrams depict transformers, main distribution boards, protective devices, busbars, feed lines, and motors, indicating conductor cross-sections, protective device ratings, and starting methods (star-delta, soft start, variable frequency drive). These diagrams are essential for calculating capacities, sizing protective devices, and ensuring the safety of the installation.
The control and operating diagrams include all control devices (pushbuttons, selectors, limit switches, sensors), relays, auxiliary contactors, and hardwired logic, as well as the control component managed by programmable logic controllers (PLCs). In many modern installations, hardwired logic is reduced to the bare minimum, and most of the sequence is handled by the PLC software, but control diagrams are still essential for understanding how the various elements are interconnected.
Another essential set consists of the input/output diagrams for programmable logic controllers (PLCs) . These diagrams show the assignment of each sensor and actuator to a physical I/O address: digital, analog, or special (high-speed counters, weighing modules, etc.). Clarity in these diagrams is vital, as they directly link the physical world to the PLC program, facilitating both commissioning and subsequent troubleshooting.
In electropneumatic installations, pneumatic and electropneumatic schematics are included , showing the compressed air network, distribution valves, cylinders, pressure regulators, air preparation elements, and actuators. The diagrams also detail how these valves are electrically controlled from relays or PLC outputs, thus integrating pneumatic control into the overall automation system.
To efficiently develop and manage all these technical drawings, it is common to use specific electrical engineering tools such as CADeSIMU or ePLAN Electric , which offer advanced functions for creating schematics, automatically generating lists of cables, terminal blocks and components, and managing modifications and versions throughout the project lifecycle.
Use of CADeSIMU and ePLAN Electric in documentation
Specialized software such as CADeSIMU and ePLAN Electric has become an indispensable tool for automation technicians, not only for designing schematics but also for generating and maintaining up-to-date documentation for industrial installations. These tools allow them to go beyond traditional drawing to work with highly structured projects.
With CADeSIMU , for example, electrical schematics can be created and simulated in a didactic way, which is very useful in training. Users can assemble circuits, test their behavior, and verify contact logic before implementing them in the real world. This reinforces the understanding of classic automation systems (direct start, interlocks, reversing) and facilitates the subsequent transition to more complex PLC-controlled systems.
ePLAN Electric, on the other hand, is geared towards larger industrial projects, allowing the creation of professional schematics with advanced cross-reference management, automatic cable numbering, bill of materials generation, and associated documentation. The major advantage is that the schematic is transformed from a simple drawing into a coherent technical database.
With these tools, technicians can automatically generate lists of cables, terminal blocks, PLC terminals, and labels , significantly reducing transcription errors and documentation time. Furthermore, subsequent modifications are reflected in all related documents, making it easy to keep documentation up-to-date even after multiple installation upgrades.
Another advantage is the ability to apply company standards using macros and templates . Common circuit blocks, such as motor starters, valve groups, or safety modules, can be saved as reusable templates with their references, text, and connections, speeding up design and ensuring document consistency across different projects and technicians.
Budgets and price databases in automation projects
The documentation for an automation project is not limited to the purely technical aspects; it also includes the preparation of detailed budgets . These budgets are typically compiled using price databases , which list the costs of materials, labor, external services, and other items necessary to carry out the installation.
These databases record PLCs, modules, electrical panels, conduits, wiring, sensors, actuators, pneumatic components, and other elements, each with its unit price, applicable discounts, and supplier references. These elements can be imported from the technical project and bills of materials generated with tools like ePLAN, and their corresponding prices can be assigned.
Integrating the bill of materials (BOM) with the budget prevents discrepancies between the design and the quoted product. If a component is updated during the project (for example, by changing the type of drive or adding additional I/O modules), the budget can be recalculated more reliably, avoiding cost surprises and issues with the client.
The budgets also include sections for labor costs related to assembly, cabling, programming, and commissioning . These are calculated based on estimated hours per task, derived from experience or historical data. Well-structured technical documentation helps to make these estimates more accurately, as it clearly illustrates the true complexity of the installation. Proper commissioning planning is key to managing both time and costs.
Furthermore, certain facilities include supplementary economic annexes , such as return on investment (ROI) analyses, comparisons between different technological solutions, breakdowns of optional features, and future expansion plans. All of this information forms part of the project documentation and influences the end client's decision-making.
Annexes on quality, environment and preventive maintenance
A complete industrial automation project is typically accompanied by appendices and manuals for quality management , environmental management, and maintenance plans. These elements complement the purely technical documentation and align with the company's management systems (ISO 9001, ISO 14001, ISO 45001, etc.).
In the area of quality, these include verification procedures, functional tests, commissioning checklists , and acceptance protocols. These documents define how the installation is verified to meet design requirements, what tests are performed on the control panels, what tests are carried out on protective devices, and what records must be kept.
From an environmental perspective, the documentation includes instructions for waste management, handling hazardous components (batteries, equipment containing oils, electronic components), and recommendations for minimizing energy consumption and emissions. In automation, this may include the optimal configuration of variable frequency drives, energy-saving modes during shutdowns, and the selection of high-efficiency equipment.
Regarding maintenance, the appendices describe preventive and predictive maintenance plans , specifying periodic tasks (adjustments, inspections, lubrication, filter changes, connection checks), recommended frequencies, and necessary resources. In advanced systems, predictive maintenance techniques are incorporated, using data from sensors and monitoring systems to anticipate failures in motors, bearings, or electronic components.
These annexes are integrated with the rest of the technical documentation to form a coherent set that not only describes how the installation is made, but also how it should be operated safely, efficiently and sustainably throughout its useful life, something increasingly valued by industrial companies and administrations.
Training content: technical documentation for the Higher Technician in Automation and Industrial Robotics
Within the training cycle of Higher Technician in Automation and Industrial Robotics , the subject or module of Technical Documentation systematically develops all the concepts mentioned, with the aim that the future technician masters both the reading and preparation of documentation in real projects.
This module covers everything from the types of documents in an industrial project (reports, drawings, manuals, appendices) to the practical use of CAD tools and specialized software, including standards for symbology, representation, and document standardization. Students learn to use applications such as AutoCAD for general drawings and programs like CADeSIMU or ePLAN Electric for electrical and control systems.
Works on this subject typically include numerous figures, illustrations, and wiring diagrams for power, control, and PLC inputs/outputs, as well as tables with component designations and examples of solved problems. This combination of theory and practice enables technicians not only to "read" a diagram but also to create one from scratch with professional expertise.
Furthermore, emphasis is placed on integrating documentation with quality management and maintenance , explaining how to prepare preventive maintenance annexes, how to reflect safety procedures in documents, and how to structure manuals that are truly useful for the end user and not simply formal documents.
This training approach is complemented by other reference materials, such as introductory books on automaticity and industrial automation, which help to contextualize the documentation within the body of knowledge on control systems, regulation, robotics and industrial communications.
Documentation and manuals in industrial automation form a technical and organizational foundation without which it would be impossible to reliably, safely, and efficiently design, implement, and maintain modern installations. Mastering this area, both practically and in terms of regulations, has become an essential skill for any professional seeking to develop a career in automation and robotics applied to industry.
