DOLD RK6929 Extension Module

01-07-2026

Have your safety controller outputs reached their limits?

Modern safety control systems are increasingly compact, intelligent and flexible. However, in many machine and plant applications, the integrated switching outputs of a safety controller, light curtain or safety sensor may not provide the switching capacity required by downstream actuators.

This is where contact extension becomes important.

The DOLD RK6929 SAFEMASTER extension module provides a compact and reliable way to extend safety-related control systems. With forcibly guided relay contacts, potential-free switching and galvanic isolation between input and output, it helps design and control engineers bridge the gap between modern electronic safety outputs and real-world actuator switching requirements.

In a housing just 17.5 mm wide, the RK6929 is designed for applications requiring additional contacts, contact reinforcement or separation between control and power levels — without taking up unnecessary space in the control cabinet.

A compact solution for contact extension

Where the switching outputs of a safety controller, light curtain or safety sensor are not sufficient for the required load or number of contacts, the RK6929 provides contact amplification, contact multiplication and galvanic isolation in a narrow DIN-rail housing. As an output extension for safety-related control signals, including OSSD outputs, the RK6929 also enables reliable relay-based switching of downstream actuators. This makes it suitable for applications where electronic safety outputs need to control higher-load devices, or where relay-based separation is required within the safety circuit.

Designed for functional safety applications

At the heart of the RK6929 is the DOLD OA5642 safety relay, featuring forcibly guided contacts in accordance with IEC 61810-3. When used with a compatible higher-level safety switching device, the RK6929 can support applications up to Cat. 4 / PL e or SIL 3. This makes the module suitable for demanding machine building and plant engineering applications where reliable contact behaviour and safe signal extension are essential.

Compatible with modern safety outputs

The RK6929 can be activated by safety-related semiconductor outputs, including OSSD outputs with test pulses. In addition, its input corresponds to interface type C, class 1 according to CB24I, supporting integration with modern safety controllers and sensors.

For UK design and control engineers, the RK6929 combines compatibility with modern safety controllers and sensors with the practical advantages of relay-based, potential-free output switching.

UL-approved version for export machine building For machine builders and panel builders supplying international markets, component approvals can be a critical part of project specification. The RK6929 is available in a UL-approved/listed version, supporting applications where UL certification is required or expected — particularly for machinery and control panels intended for North American markets. As a result, engineers and panel builders have greater flexibility when designing safety control systems for export, helping meet market expectations without changing the core contact extension approach.

Suitable for specialist applications

In addition to machine and plant engineering, the RK6929 is also suitable for use in firing systems in accordance with BS EN 50156-1.

For applications within the scope of BS EN 61010-1, the module’s clearances and creepage distances between mains circuits and touchable voltages, and between mains circuits, are dimensioned according to double insulation.

This extends the module’s relevance beyond standard machine control and into more specialist industrial safety environments.

For detailed technical information, view the RK6929 datasheet.

Typical applications:

The RK6929 is suitable for a wide range of industrial safety control applications such as:

• Automated production lines where safety controllers need to switch multiple downstream devices

• Conveyor systems with emergency stops, guard doors, light curtains or access protection

• Packaging machinery where compact safety control panels are common

• Material handling systems, including transfer systems, palletisers and automated handling equipment

• Machine tools such as CNC machines, presses, cutting machines and machining centres

• Robotic cells where safety outputs need to interface with actuators, contactors or external safety circuits

• Assembly machines with multiple guarded access points or safety interlocks

• Processing machinery used in food, pharmaceutical, plastics or chemical production

• Furnace and burner-related equipment, particularly where firing systems fall within BS EN 50156-1

• Test rigs and industrial control equipment where BS EN 61010-1 considerations may apply

• Export machinery and control panels where a UL-approved/listed version may be required for North American markets

Key benefits at a Glance:

• Compact 17.5 mm housing helps save valuable control cabinet space

• Up to two separately controllable forcibly guided relays for flexible safety contact extension

• Potential-free relay contacts for reliable actuator switching

• Galvanic isolation between input and output to decouple control and power levels

• Suitable for OSSD outputs and safety-related semiconductor outputs with testing

• Interface type C, class 1 according to CB24I

• Supports applications up to Cat. 4 / PL e or SIL 3 when used with a compatible higher-level safety switching device

• UL-approved/listed version available for export machine and panel building applications

• Suitable for firing systems according to BS EN 50156-1

• Designed with clearances and creepage distances according to double insulation requirements for BS EN 61010-1 applications

• Removable terminals available in screw and cage clamp technology for practical installation and maintenance

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