Omron G9SE-221-T05 Safety Relay Unit

Technical Overview

Compact 24VDC safety relay with 2 NO instantaneous and 2 NO off-delay outputs. Features 5s max delay time, 15ms response, and push-in terminals.

Key Features

Slim design saves mounting space.
Simple front-side wiring with Push-In Plus terminal blocks for quick installation.
Intuitive LED indicators for fast and accurate troubleshooting.
Two instantaneous safety outputs (DPST-NO) and two OFF-delayed safety outputs (DPST-NO).
OFF-delay time configurable in 16 steps from 0 to 5 seconds.
Achieves up to PLe according to EN ISO 13849-1 and SIL 3 according to EN 61508.
Certified for lift standards EN 81-1 and EN 81-2.

Technical Specification Matrix

Parameter	Value
Rated Supply Voltage	24 VDC
Operating Voltage Range	-15% to 10% of rated supply voltage
Rated Power Consumption	4 W max
Safety Outputs (Instantaneous)	DPST-NO
Safety Outputs (OFF-delayed)	DPST-NO
Auxiliary Output	PNP transistor output, 100 mA DC max load current
Max. OFF-delay Time	5 s
Response Time (ON to OFF state)	15 ms Max
Operating Time (OFF to ON state)	100 ms Max
Contact Resistance	100 mΩ Max
Degree of Protection	IP20
Ambient Operating Temperature	-10 to 55 °C
Mounting Style	DIN Rail Mount
Physical Weight (kg)	0.18
Dimensions L x W x H (cm)	0 x 2.25 x 0

Industrial Applications

1. Machine Guard Door Monitoring with Delayed Access

Used to monitor a safety interlock switch on a machine guard door. When the door is opened, the instantaneous safety outputs immediately cut power to hazardous motion (e.g., a spindle), while the off-delay outputs keep a solenoid lock engaged for a preset time until the machine has fully stopped, preventing premature access.

Problem Solved

Ensures that operators cannot access a hazardous area until the machine has reached a safe state, even after the guard door is opened. The adjustable off-delay (up to 5s) allows tuning for different machine coast-down times.

Safety InterlockGuard DoorOff-Delay SafetyPLeSIL 3Solenoid Lock

2. Emergency Stop for Conveyor Systems with Sequential Shutdown

Integrated into a conveyor line's emergency stop circuit. When an E-stop button is pressed, the instantaneous outputs halt the main conveyor drive. The off-delay output allows an upstream feeder conveyor to continue running for a few seconds, clearing product and preventing jams during the emergency stop event.

Problem Solved

Provides a safe and orderly shutdown of a multi-stage process, preventing material jams and equipment damage that can be caused by an abrupt, simultaneous stop of all components. The 24VDC supply and fast 15ms response are ideal for typical control circuits.

Emergency StopE-StopConveyor SafetySequential ShutdownOff-Delay Output

3. Light Curtain Protection for Robotic Cells with Power-On Delay

Connects to the OSSD outputs of a safety light curtain guarding a robotic work cell. If an operator breaches the curtain, the instantaneous outputs stop the robot immediately. The off-delay feature can be used in reverse logic; upon clearing the area and resetting, the delay timer can stagger the startup of different cell components, ensuring a safe and controlled restart sequence.

Problem Solved

Provides immediate hazardous motion stop upon intrusion while enabling a controlled, staggered power-up sequence upon reset, preventing high inrush currents or unsafe initial machine states. The IP20 rating and slim profile are suitable for typical control cabinet installations.

Light CurtainRobotic Cell SafetyOSSDControlled RestartSafety Relay