DOLD BD5935 Replacement for SAFEMASTER Safety Relay

Product Overview

DOLD BD5935 Replacement for SAFEMASTER Safety Relay: Seamless Transition & Legacy System Compatibility

The DOLD BD5935 is a core safety relay module from the SAFEMASTER series, engineered for emergency stop monitoring, safety gate supervision, and two-hand control circuits in industrial automation environments. For facilities operating aging safety systems built around discontinued or end-of-life DOLD modules, the BD5935 represents a proven, drop-in-compatible upgrade path that minimizes engineering rework, reduces downtime, and preserves existing wiring infrastructure.

Whether your plant is migrating from an older DOLD UH6926 or BD5930 safety relay, or replacing a failed unit within an existing SAFEMASTER safety circuit, the BD5935 delivers the same DIN-rail mounting footprint, identical terminal assignments, and equivalent safety category compliance — allowing your maintenance team to complete the swap without rewiring the control cabinet or reprogramming the upstream PLC.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful safety relay migration rarely involves a single component. When upgrading or replacing the BD5935 within a broader control system, the following components are commonly involved in the same retrofit project:

In many installations, the BD5935 interfaces directly with a Siemens SIMATIC S7-300 or S7-1200 series PLC via hardwired digital input modules such as the SM 321 or SM 1221. The safety relay’s output contacts feed directly into the PLC’s DI terminals, so verifying input voltage compatibility (typically 24 V DC) is the first step before commissioning. For systems using a Siemens ET 200SP distributed I/O rack, the BD5935 can be wired to the F-DI safety input modules without any protocol conversion.

Where the legacy system used a DOLD UH6926 or an older BD5930 module mounted in a compact control cabinet, the BD5935 fits the same DIN-rail slot. If the cabinet also houses a DOLD MK7847 or MK9160 speed monitoring relay, these units can remain in place — the BD5935 does not affect their wiring or function. Similarly, if a PILZ PNOZ X series relay was used as a secondary safety channel, the BD5935 can operate in parallel without signal interference.

For facilities upgrading the entire safety circuit, it is common to simultaneously replace the emergency stop pushbutton assemblies (typically 22 mm panel-mount units with NC contacts), the safety gate position switches, and the associated terminal blocks. Using Phoenix Contact or Weidmüller DIN-rail terminal blocks with the same pitch ensures the existing cable lengths remain usable. If the control cabinet also contains a Schneider Electric Zelio Logic smart relay or a Mitsubishi MELSEC FX series compact PLC, the BD5935’s output contacts can be wired to their digital inputs using the same 0.75 mm² control cable already in place.

In applications where the BD5935 monitors a two-hand control station on a press or stamping machine, the upstream power supply — typically a 24 V DC SITOP PSU100S or equivalent — should be verified for adequate current capacity after adding the replacement module. No firmware changes or programming tools are required for the BD5935 itself, as it is a hardwired safety device with no software configuration.

Retrofit Guidance FAQ

Q: Can I replace the BD5930 with the BD5935 without rewiring?
A: Yes. The BD5935 uses the same terminal layout and DIN-rail footprint as the BD5930. In most installations, the existing control cable can be reconnected terminal-for-terminal. Always verify supply voltage and output contact ratings against your circuit diagram before energizing.

Q: Does the BD5935 require any PLC program changes?
A: No. The BD5935 is a hardwired safety relay with no fieldbus or digital communication interface. It operates independently of PLC logic. Your existing ladder diagram or function block program does not need modification.

Q: Is the BD5935 compatible with both single-channel and dual-channel E-Stop wiring?
A: Yes. The BD5935 supports both single-channel and dual-channel emergency stop input configurations. Dual-channel wiring is recommended for Cat. 3 / PLd and above applications per EN ISO 13849-1.

Q: What is the physical installation space requirement?
A: The BD5935 mounts on a standard 35 mm DIN rail and occupies approximately 22.5 mm of rail width — identical to the BD5930 and most SAFEMASTER series modules. No additional cabinet space is required for a direct replacement.

Q: Can the BD5935 be used with third-party safety PLCs such as Pilz PNOZmulti or Siemens S7-1500F?
A: Yes. As a hardwired safety relay, the BD5935 is system-agnostic. Its output contacts can be wired to any safety PLC’s digital input or F-DI module regardless of brand or protocol.

Warranty Assurance

Every DOLD BD5935 unit shipped by TOPNLMS is covered by a 12-month warranty from the date of delivery. Prior to dispatch, each module undergoes functional verification including input channel continuity, output contact switching, and reset circuit operation. Units are packaged in anti-static protective packaging with original labeling and documentation where available.

In the event of a confirmed defect within the warranty period, TOPNLMS provides replacement dispatch or full refund support. Our technical team is available to assist with installation questions, wiring verification, and compatibility confirmation before and after purchase. Typical order processing is 1–3 business days, with DHL Express and FedEx International Priority available for urgent replacement requirements.

For volume procurement, OEM replacement programs, or standing purchase orders, please contact our sales team directly to discuss lead times, pricing, and consignment stock arrangements.