A wiring diagram is the basis for safe, efficient, and traceable work with hydraulic and electrical systems in concrete demolition, during strip-out, in rock excavation and tunnel construction, as well as in natural stone extraction. It shows how energy is provided, controlled, and safeguarded—from the power unit via valves and lines to tools such as concrete pulverizers or rock and concrete splitters. Anyone who can read and create wiring diagrams reduces downtime, increases operational safety, and creates reliable documentation for service, retrofit, and special operations.
Definition: What is meant by wiring diagram
A wiring diagram is a technical representation of the function and interconnection of components. It describes the interaction of energy sources, control and regulating elements, and actuators. In practice, this often comprises two layers: the hydraulic schematic (hydraulic diagram) for pressure fluid and the wiring diagram (electrical circuit diagram) for electrical power supply and control. For demolition tools from Darda GmbH—e.g., concrete pulverizers, rock and concrete splitters, combination shears, multi cutters, steel shears, tank cutters—the wiring diagram defines how pressure is generated, movements are triggered, forces are limited, and emergency functions are implemented. A good wiring diagram is unambiguous, compliant with standards, version-controlled, and contains all necessary operating and safety information.
Structure, symbols, and standards of the wiring diagram
Wiring diagrams use standardized symbols, clear designations, and clear signal flows. Hydraulic and electrical parts are shown separately but linked. This preserves traceability of how an electrical control signal actuates a hydraulic valve and thus triggers a movement at the tool.
Hydraulic symbols and functional groups
Typical symbols include pump, tank, pressure relief valve, check valve, directional control valve, throttle, flow divider, accumulator, cylinder, and measuring points. For tools such as concrete pulverizers, the double-acting cylinder is central, supplemented by overload-protected valves. For rock and concrete splitters, pressure generation, pressure intensification, and safe pressure relief are crucial. Color codes (e.g., P for pressure, T for tank, A/B for work ports) and direction arrows make reading easier.
Electrical symbols and control logic
In the wiring diagram you will find symbols for motor, contactor, fuse, motor protection, relay, sensor, limit switch, emergency stop, solenoid coils, and operating elements. A typical structure is: power supply – main switch – protective devices – motor circuit – control circuit (e.g., 24 V) – outputs to the solenoid valves. The logic defines when valves switch, how pressure is built, and which interlocks ensure safety.
Hydraulic schematics for demolition tools
Hydraulic power units supply tools with pressure oil via hoses. The hydraulic schematic shows generation, distribution, control, and protection of the flow rate.
Concrete pulverizers: forces, speed, and holding functions
In concrete pulverizers, movement is generated by a double-acting cylinder. The hydraulic schematic usually includes:
- Pressure relief valve to limit maximum load
- Pilot-operated check valve (load-holding or counterbalance valve) for secure position holding
- Directional control valve for directional control (open/close)
- Fine throttle or proportional control for speed adjustment
- Test ports for diagnostics with a pressure gauge
This arrangement enables rapid approach with reduced pressure and powerful pressing while limiting peak pressures—important in concrete demolition and special deconstruction.
Rock and concrete splitters: pressure intensification and relief
Splitters require very high pressure for short periods. The hydraulic schematic shows pressure generation, possibly with an intensifier stage, a defined pressure hold function, and safe pressure relief. Important building blocks are check valves to avoid pressure loss, pressure release valves for controlled decay, as well as robust filter and fine-filtration stages for long service life in rock excavation, tunnel construction, and natural stone extraction.
Electrical wiring diagrams of power units
Electrical diagrams describe the power supply and control of the unit. Typical contents are:
- Power supply, main switch, protective and shutdown devices
- Motor start (e.g., direct start or soft-start strategy) and motor protection
- Control voltage supply, protection, and emergency-stop chain
- Outputs to solenoid valves, pressure switches, sensors
- Connections for remote control or operator terminal
The clear separation of power and control circuits, clean conductor identification, and unambiguous terminal numbering are central for service and troubleshooting—especially during strip-out and cutting operations, where reconfiguration is frequent.
Safety functions in the wiring diagram
Safety is made visible in the wiring diagram. This includes:
- Emergency stop with defined effect (bring to a safe low-energy state, safely relieve pressure)
- Pressure limitation and overpressure bypass to protect components
- Interlocks against unintended movements, e.g., via pilot-operated check valves
- Non-return holding functions when working overhead or in tunnels
- Measuring and test ports for regular functional checks
Safety functions must be designed for the task; the wiring diagram documents their implementation and facilitates inspection and maintenance procedures.
Practical procedure: reading a wiring diagram
- Check the frame: title, unit/tool, revision, voltages, pressures, media.
- Understand the supply: power feed (electrical), pump and tank (hydraulic).
- Trace the control: from the operator element through logic/relays/coils to the directional valve.
- Identify actuators: cylinders, motors, splitter cylinders; trace connections A/B.
- Recognize safety: emergency stop, pressure limitation, holding valves, interlocks.
- Note measuring points: pressure gauges, pressure sensors, flow measuring points.
- Check return and case-drain lines: correct return to tank.
- Verify interfaces to tools: labeling of quick couplers.
Create and document the wiring diagram
When creating it, clarity and maintainability are crucial. Recommended are:
- Consistent identification of components, lines, and terminals
- Functionally separated representation (supply, control, actuation)
- Unambiguous signal flows and references (cross-references between sheets)
- Measuring and test points for service and commissioning
- Maintenance of revisions with change index and date
- Legend and abbreviations that match the diagram
For the application areas of concrete demolition, strip-out, and rock operations, it is advisable to proactively consider environmental influences such as dust, humidity, and temperature, as well as to integrate protection and filtration concepts.
Typical failure patterns and how to prevent them
- Unclear or missing pressure limitation: leads to overload on concrete pulverizers or splitter cylinders.
- Work ports A/B swapped: inverted tool behavior.
- Incomplete return paths: thermal overload or pump cavitation.
- Missing holding valves: unintended yielding under load, e.g., in overhead operations.
- Poor grounding/protection in the wiring diagram: failure or nuisance trips.
- No measuring points: diagnostics become unnecessarily difficult, downtime increases.
Countermeasures include clear symbols, verifiable safety chains, documented test ports, and traceable wiring.
Interfaces: thinking hydraulic schematic and wiring diagram together
Hydraulic functions are often triggered electrically. The wiring diagram should therefore consistently show which electrical signal triggers which hydraulic function. Examples include actuating the solenoid coils on directional valves or evaluating pressure switches for motor shutdown. The same principle applies to combination shears, multi cutters, steel shears, and tank cutters: only the linkage of both parts of the diagram makes the function fully transparent.
Field application: from strip-out to tunnel construction
Concrete demolition and special deconstruction
Tool changes are common during deconstruction. Wiring diagrams therefore account for identified quick couplers, defined case-drain lines, and adjustable pressure levels. For concrete pulverizers, holding valves and sensitive throttles are important to grip and crush components in a controlled manner.
Strip-out and cutting
When cutting in existing structures, compact units with a clear emergency-stop chain and quieter operation are frequently used. The wiring diagram shows reduced control voltages and separate releases; the hydraulic schematic ensures repeatable movements.
Rock excavation and tunnel construction
Here, robust pressure generation, reliable filtration, and safe holding functions are paramount. For rock and concrete splitters, pressure build-up and controlled pressure relief must be clearly defined to split rock precisely.
Natural stone extraction
Consistent quality requirements demand reproducible hydraulic functions. Wiring diagrams define how pressure and flow control the splitting process and which sensors are used for process monitoring.
Special operations
Special boundary conditions (confined spaces, explosive atmospheres, increased hygiene requirements) require adapted wiring diagrams with additional interlocks, redundant monitoring, or special energy limitation.
Best practices for planning, operation, and service
- Clear title block with unit, tool, media, pressures, and voltages
- Consistent identification of lines, terminals, and components
- Test ports at critical points (P, A, B, case drain, temperature)
- Documented emergency-stop function with tested direction of action
- Filtration and return-flow concept for dusty, hot, or cold environments
- Regular diagram maintenance: incorporate and mark changes promptly
- Supplement pages for commissioning records and pressure settings
Practical details: what often makes the difference in the wiring diagram
- Placement of the pressure relief close to the pump for effective protection
- Load-pressure-compensated throttles for constant speed under varying load
- Pilot-operated check valves mounted directly on the cylinder of the concrete pulverizer
- Clean separation of tank and case-drain lines on motors and valves
- Switching sequence for soft start and controlled depressurization
- Plug and wiring diagrams that cross-reference unambiguously with the wiring diagram
Documentation and testing
A complete wiring diagram is supplemented by inspection and maintenance notes. These include commissioning parameters (e.g., target pressure values), test intervals for safety functions, and the designation of measuring points. This enables units and tools—from concrete pulverizers to combination shears to tank cutters—to be diagnosed efficiently and safely in service cases.