Omron G9SE-221-T30 Safety Relay Unit

Technical Overview

Compact 24VDC safety relay with 2 instantaneous and 2 OFF-delayed (30s max) outputs. PLe/CAT4 compliant with IP20 rating and screw-less push-in terminals.

Key Features

Two instantaneous safety outputs (DPST-NO)
Two OFF-delayed safety outputs (DPST-NO)
Maximum OFF-delay time of 30 seconds, adjustable in 16 steps.
Slim design with a width of 22.5 mm to save panel space.
Screw-less Push-In Plus terminal block for easy and quick wiring.
Intuitive front-facing LED indicators for error diagnosis.
Supports dual-channel inputs for safety devices like E-stops and door switches.
Compliant with PLe / CAT4 safety standards.

Technical Specification Matrix

Parameter	Value
Rated Supply Voltage	24 VDC
Operating Voltage Range	-15% to 10% of rated supply voltage
Power Consumption	4 W max.
Instantaneous Safety Outputs	DPST-NO, 2 contacts
OFF-Delayed Safety Outputs	DPST-NO, 2 contacts
Auxiliary Output	1 PNP transistor output (100 mA DC max.)
Max. OFF-delay Time	30 s
Response Time (ON to OFF)	15 ms Max
Operating Time (OFF to ON)	100 ms Max
Environmental Rating	IP20
Safety Category	PLe / CAT4
Operating Temperature	-10 to 55°C
Mounting	DIN Rail
Terminal Type	Spring-loaded / Screw-Less
Physical Weight (kg)	0.18
Dimensions L x W x H (cm)	11.2 x 2.25 x 12.4

Industrial Applications

1. Safety Guard Door with Controlled Inertial Stop

A large industrial grinder is enclosed by a safety guard door. Upon opening the door, the machine must stop. However, an abrupt stop would damage the grinding wheel and motor. The G9SE-221-T30 controls this process.

Problem Solved

The relay's instantaneous outputs immediately cut power to auxiliary systems, while the OFF-delayed output (set to 12 seconds) signals the motor's VFD to perform a controlled ramp-down before disengaging the main power contactor. This prevents mechanical shock and equipment damage.

OFF-delayPLe / CAT4Guard DoorInertial LoadVFD IntegrationControlled Stop

2. Phased Conveyor Shutdown for E-Stop

On a packaging line, multiple conveyor belts transport products in sequence. An emergency stop must not cause products to pile up and jam the system between sections.

Problem Solved

When an E-stop button is pressed, the G9SE-221-T30's instantaneous outputs immediately halt the upstream conveyor. The delayed outputs allow the downstream conveyor to run for an additional 4 seconds, clearing the transition zone and preventing product jams, which would otherwise require significant downtime to clear.

Emergency StopConveyor ControlInstantaneous OutputOFF-delayed OutputMaterial HandlingJam Prevention

3. Robotic Cell Access with Timed Solenoid Lock

Access to a robotic welding cell is protected by a gate with a solenoid-activated guard lock. The gate must remain locked until the high-speed robot has fully ceased all motion.

Problem Solved

A stop signal triggers the G9SE's instantaneous outputs to cut the robot's motive power. The OFF-delayed output is wired to the gate's solenoid lock and is set for 8 seconds—a duration longer than the robot's worst-case stopping time. This ensures the gate remains securely locked until the hazard of robot motion is completely eliminated.

Guard LockingSolenoid LockRobotic CellTime Delay SafetyAccess Control24 VDC