The DA31 series safety relay by DAIDISIKE is a compact, reliable device for industrial safety, monitoring emergency stops, safety light curtain signals, safety door interlocks and two-hand controls. Used in industries like CNC, robotics, and hydraulics, it is rated to EN ISO 13849-1 Cat. 4 / PL e and IEC 62061 SIL 3 per the manufacturer's specification. Its ultra-slim 22.6 mm housing, configurable dual-channel input and separate transistor status output help streamline installation and reduce wiring complexity.
3 Normally Open forcibly guided safety contacts + 1 Normally Closed auxiliary signalling contact; verify terminal numbering on the supplied unit
Wiring revision
Use the delivered label and matching wiring diagram: supplied illustrations differ in power/reset terminal names and show 41/42 or 43/44 for the auxiliary contact. Do not interchange these terminal maps.
Transistor Signal Output
<500mA, 24V DC
Safety Input
Dual-channel input. Factory wiring examples show PNP light curtains and contact-based devices; confirm NPN and OSSD test-pulse compatibility against the exact supplied revision's instructions.
Input Modes (DIP-switch selectable)
Multifunction DIP configuration for applications including emergency stop, safety light curtain, guard-door switch and two-hand control; use the mode table for the supplied revision.
12A (distributed across all safety output contacts)
Contact Resistance
<100 mΩ
Minimum Load
10mA / 5V
Contact Material
AgSnO2 + 0.2 µm Au
External Output Fuse
5A gL/gG
Release Response Time
<30ms (from input to output)
Electrical Life
80,000 operations
End-of-line Detection Resistance (safety edge / safety mat inputs)
1 kΩ – 10 kΩ
Rated Impulse Withstand Voltage
2.5 kV
Pollution Degree
2
Safety Level
EN ISO 13849-1 Category 4 / PL e; IEC 62061 SIL 3 (manufacturer brochure/label; obtain exact-model supporting documents)
Operating Temperature
-25°C to +85°C
Storage Temperature
-40°C to +105°C
Operating Humidity
35% – 85% RH (no icing or condensation)
Installation Method
Standard 35 mm DIN rail / spring clip
Dimensions
112mm × 99.5mm × 22.6mm
Weight
172 g
Protection Grade
Housing IP30, terminals IP20 — install inside an IP54 cabinet or enclosure
Housing Material
Flame-retardant PA66
Certification
Contact factory for certification documents
Technical Parameters of DA31 Series Safety Relay
The technical parameters of the DA31 series focus on safety performance and electrical characteristics. The power supply is 24V DC, with a tolerance range of +10% to -20%, and power consumption of 2.9W. The input stage is a dual-channel safety input with multifunction DIP configuration for applications including emergency stop, safety light curtain, safety door interlock and two-hand control. Factory diagrams illustrate PNP and contact-based inputs; verify any NPN or pulsed OSSD connection against the instructions for the supplied revision. The output provides 3 forcibly guided normally open safety contacts and 1 normally closed auxiliary contact, with terminal numbers verified on the delivered unit. Contacts are rated AC-1 6A/250VAC with a maximum total current of 12A, plus a separate transistor signalling output below 500mA at 24V DC. The response time is less than 30ms, ensuring quick release. The operating temperature range is -25°C to +85°C and storage is rated -40°C to +105°C. The module is rated to EN ISO 13849-1 Cat.4/PLe and IEC 62061 SIL 3 according to the manufacturer's specification. The housing is flame-retardant PA66 with IP30 protection (IP20 at the terminals), so the module is designed to be mounted inside an IP54 cabinet or enclosure on a standard 35 mm DIN rail. Request the exact model's safety documentation; the factory brochure and company certificates do not by themselves validate a complete machine safety function.
Working Principle of DA31 Series Safety Relay
The core working principle of the DA31 series safety relay is based on a dual-channel safety input architecture: two independent input channels are monitored, so the safety function does not depend on a single channel. When the connected safety device is actuated, the module drops out and the forcibly guided contacts open to remove power from the hazardous machine function.
The specific workflow is as follows:
Input Detection: The dual-channel safety input receives signals from the connected safety device — an emergency stop button, a safety light curtain's OSSD outputs, a safety door interlock switch or a two-hand control station. Factory diagrams show PNP and contact-based examples; exact input and test-pulse compatibility must be checked.
Mode Selection: Use the multifunction DIP settings specified for the supplied revision. Emergency stop, light curtain, door interlock and two-hand control are example applications, not a universal four-position mode table.
Output Control: Once the required inputs and reset conditions are satisfied in the validated circuit, the three normally open safety contacts close to supply power to actuators such as motor contactors. The release response time is <30ms, ensuring quick disconnection in emergency situations. A separate transistor signalling output (<500 mA / 24 V DC) reports status to the PLC.
Fault Handling: The module uses forcibly guided (positively driven) contacts. The factory S1/S2 terminal table describes open-circuit detection and inter-channel checking. These features support fault monitoring but do not establish complete diagnostic coverage or external-device monitoring (EDM).
Application Extension: In safety light curtain applications, when an intrusion is detected by the light curtain, the input is interrupted, and the relay output requests a stop through the validated final switching devices. Measured machine stopping time remains part of the safety assessment. The documented applications also include emergency-stop, safety door interlock and two-hand control circuits.
Note: the DA31 carries a reset selector — the factory wiring diagram shows the SRC/SR terminals configured either for manual reset or, when linked, for automatic reset on that illustrated revision. Input open-circuit detection and inter-channel checking are described in the terminal table; their coverage and operating conditions require the matching manual. EDM feedback is not established by these diagrams. Reset must not initiate hazardous motion, and terminal maps from different illustrations must not be combined.
Frequently Asked Questions
What is the difference between a safety relay and a safety PLC?
A safety relay like the DA31 is a hardwired, fixed-function device that monitors emergency stops, safety light curtains or door switches through dual-channel redundant inputs and cuts output in under 30 ms. A safety PLC is programmable and scales to many zones and complex logic. For a single machine or a few safety functions, the DA31 is faster to wire and lower cost.
What safety standards and performance level does the DA31 meet?
The manufacturer brochure and product label reference EN ISO 13849-1 Category 4 / Performance Level e and IEC 62061 SIL 3. This is a manufacturer specification, not proof that a complete machine achieves those levels. Dual-channel monitoring and forcibly guided contacts support fault detection in an appropriately designed circuit; obtain exact-model supporting documents and validate the complete safety function.
What input modes and signal types does the DA31 accept?
Multifunction DIP configuration for applications including emergency stop, safety light curtain, guard-door switch and two-hand control; use the mode table for the supplied revision. Dual-channel input. Factory wiring examples show PNP light curtains and contact-based devices; confirm NPN and OSSD test-pulse compatibility against the exact supplied revision's instructions. The application examples are not a claim of exactly four DIP settings or automatic interchangeability with another manufacturer's sensor.
How is the DA31 wired and mounted?
The DA31 measures 112 × 99.5 × 22.6 mm and mounts on a standard 35 mm DIN rail. Its 22.6 mm housing width is confirmed by the factory dimension drawing. Use the delivered label and matching wiring diagram: supplied illustrations differ in power/reset terminal names and show 41/42 or 43/44 for the auxiliary contact. Do not interchange these terminal maps. Isolate power before wiring, and validate the input, reset and final switching-device circuit before operation.
What outputs and contact ratings does the DA31 provide?
The DA31 provides 3 forcibly guided normally open safety contacts plus 1 normally closed auxiliary contact for status signalling. The factory table lists AC-1 6 A/250 VAC, AC-15 4 A/240 VAC, DC-1 6 A/24 VDC and DC-13 4 A/24 VDC. DC-1 and DC-13 are different load categories, not conflicting versions of one rating. The maximum 12 A is distributed across all safety output contacts, not 12 A per contact. A separate transistor signalling output is rated below 500 mA at 24 VDC and must not be treated as a safety output. Select the contact rating for the actual load category.
