Safety Relays

Safety relay modules with forcibly guided contacts for e-stop, light curtain and door-lock circuits.

Safety Relay Modules for E-Stop, Light Curtain and Door Circuits

A safety relay module evaluates a dual-channel signal from an emergency-stop device, safety light curtain, safety door interlock or two-hand control and uses forcibly guided contacts to interrupt hazardous machine functions. It is the evaluation stage between the field safety device and the machine contactors — not the sensor, PLC or contactor itself.

DAIDISIKE lists two modules here. The DA31 e-stop safety relay is the 22.6 mm ultra-slim option with dual-channel PNP/NPN input and a separate transistor status output for a PLC. The current DQSRN safety relay module page lists a 45 mm DIN-rail housing, but source documents conflict on its dimensions, so confirm the exact shipped variant.

Emergency stop light curtain or door interlock dual-channel input through a safety relay module to machine contactors and PLC status — Field safety device → dual-channel evaluation → forcibly guided contacts → machine contactors; status can be reported separately.

DA31 Emergency-Stop Safety Relay Module

Ultra-slim 22.6 mm Category 4/PL e/SIL 3 safety relay with dual-channel PNP/NPN input and a solid-state status output.

DQSRN Safety Relay Module

DIN-rail safety relay with DIP-switch selectable E-stop, OSSD, door interlock, two-hand inputs, Cat.4/PLe/SIL3.

DA31 vs DQSRN Safety Relay Module

Both pages publish four DIP-switch selectable input modes: emergency stop, safety light curtain OSSD, safety door interlock and two-hand control. Both publish 24 VDC operation, sub-30 ms response and 3 N.O. + 1 N.C. forcibly guided contact arrangements. The selection is therefore about the documented housing, input compatibility and auxiliary signal requirement rather than a claim that one is universally ‘more safe’.

Published attribute	DA31	DQSRN
Housing width	22.6 mm	45 mm listed; source documents conflict, confirm variant
Dual-channel input	PNP or NPN	see product input-mode specification
Input modes	e-stop / OSSD / door / two-hand	e-stop / OSSD / door / two-hand
Relay contacts	3 N.O. + 1 N.C. forcibly guided	3 N.O. + 1 N.C. forcibly guided
Separate PLC status output	transistor signaling output <500 mA / 24 VDC	not listed as a separate transistor output
Response	<30 ms	<30 ms

Select by Input Device and OSSD Compatibility

For an e-stop circuit, confirm that the device channels and selected relay input mode form the required safety function; the DA31 e-stop safety relay page contains its exact input and output selection. For an OSSD light curtain, choose the published OSSD input mode and verify output polarity and test-pulse compatibility from the exact device documents. For a guard switch, verify whether the field device outputs mechanical contacts, NPN or PNP transistor channels.

DA31 is also the catalogue option for a safety relay module with PLC status output: its separate transistor signaling output can report machine run/stop status to a PLC without consuming a safety contact. This is status reporting, not programmable safety logic. The DQSRN safety relay module is the alternative when its documented housing and terminal arrangement fit the panel.

What a Safety Relay Does — and Does Not Do

The relay evaluates the selected safety input and switches its safety contacts. It does not sense a person, read a door mechanically, or replace the output contactors. It also does not make the whole circuit Category 4 / PL e / SIL 3 by itself: the achieved level belongs to the complete safety function, including the input device, logic, output elements, architecture and validation.

Neither DA31 nor DQSRN is presented here as a programmable safety relay or safety PLC. If the application needs several independent zones, configurable logic or networked diagnostics, do not force a single-function relay into that role.

For a model check, send the field safety device, output type, required number of safety contacts, load/contactors and available DIN-rail width via the inquiry form.

Frequently Asked Questions

What does a safety relay module do?

It evaluates a safety input and changes forcibly guided output contacts so downstream contactors can remove power from hazardous machine functions.

Which safety relay is suitable for a light curtain OSSD output?

DA31 and DQSRN both list an OSSD input mode. Confirm the exact light-curtain output polarity, test pulses and circuit documentation before final wiring.

Can DA31 send status to a PLC?

Yes. Its published specification includes a separate transistor signaling output below 500 mA / 24 VDC for status reporting.

Can DA31 execute configurable safety logic?

No. It uses DIP switches to select one of four published input modes; it is not presented as a programmable logic controller.

Do DA31 or DQSRN include manual reset, automatic reset or EDM?

The current product data does not publish those functions. Do not assume they are present; confirm the exact circuit documentation and use a controller architecture that explicitly provides any required reset or external-device monitoring function.

Does a Cat.4 / PL e safety relay make the complete machine circuit PL e?

Not automatically. The complete safety function must be designed and validated to the required level, and its result is limited by the architecture and every component in the chain.

What is the main selection difference between DA31 and DQSRN?

DA31 is 22.6 mm wide and lists PNP/NPN dual-channel input plus a separate PLC status output. DQSRN's current page lists 45 mm, but its source dimensions conflict; confirm the exact shipped variant and compare the terminal arrangement.

Safety Relays in Action — 1 Demonstration Videos

Wiring, setup and live operation filmed on the actual modules. Each clip links back to the series it demonstrates, so you can go straight from footage to specification.