The SR3D Safety Control Device:

The SR3D is a versatile safety control device with three secure, redundant, and diverse relay outputs, along with an additional auxiliary contact (signaling contact). It is specifically designed to safely shut down moving parts of a machine in the event of a hazard. Typical areas of application include single-channel or dual-channel emergency stop circuits and protective grid monitoring on machines and systems. With certifications from TÜV-Rheinland and Germanischer Lloyd (GL), the SR3D is also approved for use on ships and in continuous operation combustion plants in accordance with EN 50156-1 and EN 746-2.

The device supports the connection of various safety components, such as emergency stop buttons, safety switches, non-contact safety switches, and safety components with OSSD outputs. It enables both single-channel and dual-channel operation and monitors the feedback loop of downstream contactors or expansion modules. Key safety features include cross-fault and ground-fault monitoring, cyclic checking of the output contacts, and an LED display of the switching status.

The safety-related stop function is performed according to EN ISO 13849-1 / IEC 61508 up to PL e / SIL 3. If the emergency stop circuit is closed (e.g., by a closed safety door), the SR3D releases the machine. When the safety function is requested (e.g., by opening the safety door), the release current paths are immediately opened, and the machine is safely shut down. The use of force-guided relays ensures that the safety function is maintained even in the event of a device fault, with failures being detected by cyclic self-monitoring at the next safety function request.

The SR3D is designed for installation in control cabinets with a minimum protection class of IP54. Installation is carried out on a 35-mm DIN rail according to EN 60715 TH35. For the AC 115 V / 230 V variant, a minimum distance of 10 mm from adjacent devices must be maintained. To ensure this distance, the ZANDER AACHEN spacer (part no. 472596) can be used.

Technical Data:

• Safety function: Emergency stop monitoring, protective grid monitoring, cross-fault and ground-fault monitoring, cyclic checking of output contacts
• Certified according to: EN 60204-1; DIN EN ISO 13849-1; EN 62061; EN 50156-1; EN 746-2; IEC 61508 Parts 1-2 and 4-7; IEC 61511-1
• Approvals: CE, TÜV, GL
• Supply voltage: AC/DC 24 V / AC 115 V / AC 230 V
• Number of safety contacts: 3 redundant, diverse relay outputs
• Number of signaling outputs: 1 auxiliary contact (signaling contact)
• Max. switching capacity of safety contacts: 8 A / 250 VAC resistive load
• Start behavior: Monitored manual start or automatic start
• Cross-fault and ground-fault monitoring: Yes
• Single-channel or dual-channel operation: Yes
• Feedback loop for monitoring downstream contactors: Yes
• Switching state display: LED indicator
• PL; Cat.; SILCL (EN ISO 13849-1; EN / IEC 62061): PL e; Cat. 4; SILCL 3
• Width: 22.5 mm

Ordering Information:

• Part number with fixed screw terminals: 472272 (24 V) / 472271 (115 V) / 472270 (230 V)
• Part number with pluggable screw terminals: 474272 (24 V) / 474271 (115 V) / 474270 (230 V)
• Part number with push-in spring connection in TWIN version: 475272 (24 V) / 475271 (115 V) / 475270 (230 V)