Table of contents
- Why we need to know about circuit symbols
- What does DIN ISO 1219 regulate?
- Overview of the most important symbol groups
- Common mistakes when reading circuit diagrams
- Practical tip: Understanding symbols means understanding systems
- Conclusion: If you speak the language of hydraulics, you can plan more safely
- FAQs
Why we need to know about circuit symbols
Hydraulic systems are the backbone of many machines - from industrial automation and mobile hydraulics to complex control systems. But if you want to understand, plan or maintain such systems, you need to know their language: the circuit symbols.
Standardised symbols are the only way to clearly document and interpret hydraulic systems worldwide. DIN ISO 1219 creates clear rules for this. This enables developers, fitters and maintenance engineers to communicate in a standardised way, avoid errors and operate systems safely.
What does DIN ISO 1219 regulate?
The international standard DIN ISO 1219 specifies how hydraulic and pneumatic components are represented in circuit diagrams - neutrally, regardless of specific designs or manufacturers.
Important principles of the standard:
Symbolism is function-related - it is what a component does that counts, not what it looks like.
Symbols are modular - complex systems are built up from simple basic characters.
Flow directions, connections, pressure stages and control lines can be standardised.
This provides a clear overview and reduces interpretation errors.
Overview of the most important symbol groups for hydraulic circuit symbols
Energy sources: Pumps and motors
Symbol: Circle with triangle (shows direction of flow)
Adjustable components have additional arrows
Typical labelling: P (pressure line), T (tank)
Actuators: Cylinders and motors
Single- and double-acting cylinders: rectangle with piston line
Return springs or dampers are clearly labelled
Different types of lifting recognisable (e.g. telescopic cylinders)
Valves: directional, pressure and flow valves
Directional valves: Boxes with arrows, e.g. 4/3-way valve
Pressure valves: with spring and arrow (e.g. pressure relief valve)
Throttles: Arrows with adjustable or fixed limitation
Non-return valves: only allow flow in one direction
Lines and connections
Solid line: Pressure line
Dashed: Control line
Point at intersection = connection; without point = no connection
Standard designations: P, A, B, T, L, R
Storage tanks and tanks
Bubble, piston or diaphragm storage tanks clearly distinguishable
Recognisable open and closed tanks with/without ventilation
Common errors when reading circuit diagrams
"Intersection with dot" vs. "without dot": A classic - no connection without a dot!
Zero positions of valves: Locked or open positions are often read incorrectly.
Connections overlooked: P, A, B, T must be correctly identified, otherwise the circuit will not work as planned.
If you make a mistake here, you risk malfunctions or dangerous situations.
Practical tip: Understanding symbols means understanding systems
The DIN ISO 1219 symbols are more than just "technical drawings". They are a language that helps to visualise complex systems simply - provided you can read them.
Our tip:
Use symbol overviews - e.g. as posters or digital tools
Train employees regularly in reading and interpreting
Work with standardised templates - STAUFF provides technical documentation for this purpose
If you are unsure: Seek advice - e.g. from the STAUFF team
Conclusion: If you speak the language of hydraulics, you can plan more safely
Whether in design, service or troubleshooting - those who understand circuit symbols have a decisive advantage.
DIN ISO 1219 ensures clear communication, simplifies documentation and prevents errors.
With the necessary basic understanding and the right overview, hydraulic systems can be operated more efficiently, safely and transparently. STAUFF supports you in this - with expertise, experience and a standard-compliant product and documentation portfolio.
FAQs
What is a single-acting and what is a double-acting hydraulic cylinder?
Why are standardised hydraulic circuit symbols in accordance with DIN ISO 1219 important?
Standardised symbols ensure uniform, globally understandable circuit diagrams - regardless of the manufacturer or the design of a component.
Which software or tools help with reading hydraulic circuit diagrams?
CAD programmes with symbol libraries in accordance with DIN ISO 1219 and technical documents from manufacturers such as STAUFF offer practical support when planning and reading circuit diagrams.
How do I recognise whether lines are connected in a circuit diagram?
If lines intersect in a circuit diagram and there is a dot at the intersection, they are connected. Without a dot means: no connection.
Does STAUFF offer support with hydraulic planning?
Yes, STAUFF supports customers in the selection and planning of hydraulic connection solutions - from standardised components to individual system consulting.
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