Wiring diagram

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. A complete, standards-compliant diagram also supports lifecycle documentation, quick fault isolation, and transparent acceptance testing in demanding environments.

Definition: What is meant by a 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. It uses language-neutral symbols, clear identifiers, and consistent references to ensure that setup, commissioning, and service remain reproducible.

Structure, symbols, and standards of a 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. Common standards such as ISO 1219 for hydraulics and IEC 60617 and IEC 60204-1 for electrical equipment help ensure consistent notation, safety, and maintainability across revisions.

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. Line styles and markings for pilot lines, drains, and internal connections further increase clarity, especially where multiple functions are combined in one manifold.

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. Clean conductor identification, cross-references, and functional naming according to applicable standards support error-free assembly and troubleshooting, including EMC-conscious routing and shielding where required.

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. It also indicates filtration, cooling paths, and oil conditioning to maintain performance under dust, heat, and vibration.

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
• Optional regeneration circuit for rapid jaw closing at low load

This arrangement enables rapid approach with reduced pressure and powerful pressing while limiting peak pressures – important in concrete demolition and special deconstruction. Clearly indicated case-drain concepts and anti-shock protection prevent component stress when breaking heterogeneous materials.

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. Clear notation of intensifier ratios, permissible dwell times, and thermal limits ensures precise and repeatable splitting.

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
• Earthing and bonding concept, cable sizing, and labeling rules

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. Specified cable types, IP protection classes, and routing guidelines further reduce susceptibility to faults.

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
• Defined restart behavior and prevention of unexpected energization after power restoration
• Where applicable, two-channel safety circuits and safe shutdown of drives

Safety functions must be designed for the task; the wiring diagram documents their implementation and facilitates inspection and maintenance procedures. Acceptance criteria, target values, and test intervals should be specified so that proof of effectiveness can be demonstrated over the service life.

Practical procedure: reading a wiring diagram

1. Check the frame: title, unit/tool, revision, voltages, pressures, media.
2. Understand the supply: power feed (electrical), pump and tank (hydraulic).
3. Trace the control: from the operator element through logic/relays/coils to the directional valve.
4. Identify actuators: cylinders, motors, splitter cylinders; trace connections A/B.
5. Recognize safety: emergency stop, pressure limitation, holding valves, interlocks.
6. Note measuring points: pressure gauges, pressure sensors, flow measuring points.
7. Check return and case-drain lines: correct return to tank.
8. Verify interfaces to tools: labeling of quick couplers.
9. Compare references and cross-references: sheet numbers, terminal designations, and legend consistency.

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
• Unique document ID and revision control that link to released datasets
• References to component datasheets and settings for valves, sensors, and protection devices

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. Durable identification (labels, terminal markers) and readable print sizes support work on site.

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.
• Case-drain connected to pressure or restrictive return: seal damage and overheating.
• Undersized conductors or voltage drop: weak solenoid actuation and unreliable switching.

Countermeasures include clear symbols, verifiable safety chains, documented test ports, and traceable wiring. A structured review checklist prior to release significantly reduces the risk of latent errors.

Interfaces: thinking the hydraulic schematic and the 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. Clear cross-references between electric coils and hydraulic valve symbols accelerate diagnostics and prevent misinterpretation during retrofits.

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. Marked pre-sets and documented test points enable repeatable results even with frequent reconfiguration.

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. Where noise and emissions limits apply, soft-start and controlled depressurization sequences are explicitly documented.

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. Shielded wiring, rugged connectors, and redundant safety interlocks support reliable operation under shock and contamination.

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. Versioned settings and inspection notes help maintain uniform product quality across multiple sites.

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. Clearly stated operating modes and lockout procedures ensure that safety intentions are transparent and auditable.

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
• EMC-conscious cable routing, segregation of signal and power, and defined shielding points
• Spare parts mapping that references diagram identifiers for fast replacement

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
• Use of standardized test couplings and clearly labeled measuring points for safe diagnostics

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. Documented acceptance tests, defined tolerances, and revision-stable parameter sets create verifiable performance and safety over the entire lifecycle.