The DOLD UG 6918 Safety Bus Extender Module (German: Bus-Erweiterungsmodul / English: Safety Bus Extender Module) is an industrial communication and safety interconnection instrument researched and manufactured by E. DOLD & SÖHNE GmbH & Co. KG in Germany. In modern functional machinery safety topologies within the SAFEMASTER ecosystem (notably SAFEMASTER C and SAFEMASTER PRO modular safety relays), individual safety devices exchange status telemetry, control signals, and interlocking feedback via an integrated backplane bus embedded beneath the DIN rail (In-Rail-Bus). However, as automation architectures scale beyond the capacity of a single continuous DIN-rail track, or when safety modules must be decentralized across separate rail rows or adjacent satellite enclosures, preserving an unbroken, high-speed safety bus communication line becomes a vital engineering requirement.

The DOLD UG 6918 serves as a dedicated hardware bridge designed to extend and route the internal backplane bus seamlessly without compromising signal propagation speed, deterministic response times, or functional safety integrity. Instead of requiring labor-intensive, error-prone manual point-to-point hardwiring of dozens of auxiliary relay channels across enclosure tiers—which complicates wiring diagrams and increases commissioning overhead—engineers simply terminate each rail tier with a UG 6918 module. The unit accepts the complete bundle of safety control data, handshake signals, and system diagnostics, routing them reliably to the subsequent DIN-rail section via a standardized, noise-shielded communication link.

Constructed within the standardized UG enclosure format with a slim 22.5 mm width, the UG 6918 optimizes control enclosure packing density. Internally, the unit incorporates industrial-grade electromagnetic interference (EMI) filtering circuits and signal conditioning transceivers, ensuring that bus telegrams remain free from jitter or attenuation even when operating adjacent to heavy frequency inverters, servo drives, or high-power contactors. The front fascia incorporates an intuitive LED diagnostic array indicating power availability, active bus linking, transmission integrity, and localized faults, allowing field maintenance personnel to monitor the physical network status in real time.

Operating on a standard DC 24V industrial supply, the module satisfies the highest international machinery safety benchmarks—including EN ISO 13849-1 (up to Cat. 4 / PL e) and IEC/EN 62061 (up to SIL 3)—when deployed within validated SAFEMASTER configurations. The DOLD UG 6918 is an essential building block for extensive production cells, automated transfer presses, robotic welding stations, intelligent warehouse material handling systems, and high-speed packaging machinery worldwide.

• Manufacturer: DOLD (E. DOLD & SÖHNE GmbH & Co. KG)
• Country of Origin: Germany
• Product Category: Safety Bus Extension Module (Bus-Erweiterungsmodul / Bus Extender)
• Product Family: SAFEMASTER UG 6918
• Part Identifier: UG 6918 (UG6918)
• Primary Function: Bridging and extending internal In-Rail-Bus communication across separate DIN-rail tiers or remote control cabinets
• Device Compatibility: DOLD SAFEMASTER multifunctional safety relays (UG 6911, UG 6916, UG 6917, and associated expansion modules)
• Nominal Operating Voltage (UN): DC 24 V
• Voltage Tolerance Range: 0.85 ... 1.15 UN
• Power Consumption: Ultra-low, optimizing enclosure energy efficiency
• Bus Interfacing Architecture:
  - Bottom connection: Direct plug-in contact to the DIN-rail In-Rail-Bus backplane
  - Inter-rail link: High-integrity shielded communication terminal interface
• Visual Diagnostic Array: Front LEDs for power (PWR), bus communication status, transmission/reception (Tx/Rx), and fault detection
• Housing Dimensions (W x H x D): 22.5 x 100 x 121 mm (Compact UG enclosure)
• Mounting Profile: Quick snap-on mounting on standard 35 mm DIN-rail (IEC/EN 60715)
• Termination Options: Heavy-duty box clamp screw terminals or vibration-proof spring terminals
• Wire Cross-Section Capacity: Solid wire 0.2 ... 2.5 mm² or stranded wire with ferrule 0.2 ... 1.5 mm²
• Protection Degree: Housing IP40, Terminals IP20 (according to IEC/EN 60529)
• Ambient Operating Temperature: -20°C to +60°C
• Functional Safety Compliance: EN ISO 13849-1 (PL e, Cat. 4), IEC/EN 62061 (SIL 3), IEC/EN 61508, CE, TÜV Certified
• Typical Applications: Metal stamping presses, automated robotic cells, high-speed logistics conveyors, packaging machines, and CNC automated machine tools