KEYENCE GS-11N5 Non-contact Safety Gate Sensor

KEYENCE GS-11N5 Non-contact Safety Interlock Switch (GS Series Standard Type, NPN Output, 5m Pre-cabled)

Application: Non-contact interlock detection for equipment safety guards/protective doors. Used together with GS series actuators (magnetic heads). Applied to machine tools, automated production lines and robot safety fencing.

✅ Model Code Explanation

GS: GS series non-contact safety interlock switch

11: Standard main unit model

N: NPN OSSD safety output (P stands for PNP)

5: 5m pre-fitted cable with bare wire ends (GS-11N10 is the 10m cable variant)

📋 Core Electrical & Sensing Specifications

1. Power Supply: DC24V ±20%, Class 2 power supply
2. Output: Dual OSSD NPN safety transistor outputs + 1 auxiliary non-safety AUX output (max. 50mA)
3. Sensing Distance (with GS actuator)

Front mounting: Sao(OFF→ON)=10mm; Sar(ON→OFF)=18mm

Side mounting: Sao(OFF→ON)=6mm; Sar(ON→OFF)=14mm

4. Response Time

Detected → Not detected: 20ms +2ms ×(number of cascaded units −1)

Not detected → Detected: 30ms +25ms ×(number of cascaded units −1)

5. Cascading: Up to 30 units in series
6. Max. door actuation frequency: 3Hz
7. Safety Certifications

EN ISO13849-1: PLe / Category4

IEC61508: SIL3; EN ISO14119 Type4 safety switch

8. Protection: Reverse power polarity protection, output short-circuit protection, surge protection

🧵 Cable Pin Definition (8-core bare-end cable)

Wiring Notes: Dual OSSD outputs connect to safety relay / safety PLC; AUX is only for status monitoring, MUST NOT be wired into safety circuit.

📌 Selection & Matching Accessories

GS-11N5 is only the switch body. GS series actuator (magnetic head) must be ordered separately, e.g. GS-A10, GS-A20. No mechanical contact between actuator and main unit; detection relies on magnetic field.

Peer models comparison:

GS-11N5: NPN, 5m cable

GS-11N10: NPN, 10m cable

GS-11P5: PNP, 5m cable

GS-11P10: PNP, 10m cable

⚠️ Installation & Maintenance Guidelines

1. The gap between main unit and actuator must stay within rated sensing range. Reserve clearance for vibration-prone sites to prevent false triggering.
2. Do not install close to strong magnets to avoid magnetic interference.
3. For cascaded configuration, total response time increases with series quantity; safety circuit assessment must include delay.
4. Enclosure IP rating: suitable for industrial environments, avoid continuous immersion.
5. Troubleshooting priority: check power supply, cable breakage, actuator position offset first. Mismatch of dual OSSD channels usually indicates fault.

📎 Alternative Products

Similar non-contact safety gate switches: Schneider XCS-DMP, Pilz PSENmag, Omron D40A series. Note differences in safety level, OSSD type and cascading capability; direct replacement into safety circuit is not allowed.

GS-11N5 Troubleshooting Checklist (LED Indicator + Phenomenon + Remedy)

GS-11N5 equipped with tri-color LED: Green / Orange / Red. Judge fault by LED status first.

Never short OSSD channels for testing. Lock-out & tag-out equipment before modifying safety circuits.

1. LED Status Definition

2. Step-by-step Troubleshooting (from simple to complex)

2.1 Power Check (priority when no LED)

1. Measure Brown(24V+) and Blue(0V), confirm DC24V within 19.2~28.8V
2. Check reverse polarity. Built-in reverse protection prevents burnout but unit will not operate.
3. Inspect cable root for bending damage (5m cable model most prone to wire breakage at root).
4. Confirm Class2 power supply with sufficient capacity and no voltage drop.

2.2 Sensing Gap & Actuator (solid orange LED, door closed but no detection)

1. Confirm actuator is GS series (GS-A10 / GS-A20). Other brand magnetic heads cannot be used.
2. Front mounting: gap ≤10mm for activation; >10mm cannot trigger; >18mm permanently off.
3. Side mounting: Sao=6mm, Sar=14mm, stricter gap requirement.
4. Check loose mounting brackets, vibration shift, deformed metal cover squeezing main unit/actuator.
5. Check nearby strong magnets, inverters or high-current cables causing magnetic interference.

2.3 Safety Input Wiring (Most common pitfall for non-cascaded use)

For GS-11N5 (NPN), when not cascaded, the two safety inputs must be shorted to 0V (Blue wire)

Red/Black (Safety Input1) and Red/White (Safety Input2) short to 0V;

✘ Wrong: floating / connected to 24V → red fault LED.

Cascading: OSSD outputs of previous GS connect to safety inputs of next unit, channel-to-channel matching.

2.4 OSSD Dual Channel Fault (Solid Red LED)

Symptom: OSSD1 and OSSD2 status mismatch, safety relay reports channel error

1. Disconnect load and measure Black(OSSD1) and White(OSSD2) separately.
2. Check OSSD cable short to ground or inter-wire short; OSSD short-circuit protection triggers latch-up.
3. Wiring resistance limit: total loop resistance ≤2.5Ω; long/thin cables may trigger fault.
4. Capacitive load limit: max. 2.2μF; parasitic capacitance of long cables may cause timing mismatch between channels.
5. Check cross-wiring between safety relay / safety PLC channels. OSSD1 and OSSD2 must not be swapped.

2.5 AUX Auxiliary Output (Status feedback only, non-safety)

Gray AUX follows door state, only for PLC monitoring, must not be inserted into safety circuit

Door closed: AUX ON; Door open: AUX OFF

AUX abnormality does not affect OSSD safety function, only status indication.

3. Quick Fault Reference Table

4. Criteria for Main Unit Damage Replacement

Replace GS-11N5 if any condition below is met:

1. Power, wiring and actuator are fully verified correct, red LED latched and cannot reset.
2. Actuator within qualified sensing distance, green LED fails to light up.
3. OSSD channel mismatch persists even after all external loads disconnected.

⚠️ Safety Precautions

1. Shut down equipment and cut off power before safety circuit test.
2. Do not short OSSD safety outputs for commissioning.
3. Perform full safety function verification after switch replacement.
4. Max. 30 units for cascading; longer chain brings larger response delay, which must be included in safety assessment.

GS-11N5 Wiring Example for Safety PLC

Prerequisite: GS-11N5 is NPN OSSD dual safety output. This case: single unit, non-cascaded, widely used for safety gates on automated lines.

Safety PLC examples: KEYENCE KV-S04 / Pilz PNOZmulti / Siemens F-PLC. Principle is universal, terminal numbers vary by brand.

⚠️ Important: OSSD is safety transistor output, NEVER short OSSD for testing. Lock-out & tag-out before modifying safety circuit.

1. GS-11N5 Cable Assignment (Single unit, non-cascaded)

NPN OSSD Characteristics:

✅ Door closed (actuator in place): OSSD1 & OSSD2 turn ON → Black & White ≈0V

✅ Door open: OSSD1 & OSSD2 OFF → high impedance, near 24V

2. Safety PLC Side Wiring Logic (Dual-channel Safety Input)

Two common safety PLC input types:

Type A: Sourcing safety input (High level active)

GS-11N5 NPN OSSD cannot directly drive sourcing safety input

✅ Solution: Pull-up resistors (2.2kΩ /0.5W recommended) on Black & White wires to DC24V.

When door closed, OSSD pulls signal low. PLC detects consistent low level on both channels as safe state.

Type B: Sinking safety input (Low level active, recommended)

Direct connection for GS-11N5, no extra resistors needed

Safety PLC internal: safety input terminals pulled up to 24V

Black OSSD1 → Safety Input CH1

White OSSD2 → Safety Input CH2

Door closed: OSSD ON, CH1 & CH2 pulled to 0V, dual-channel consistent, safety circuit enabled

Door open: OSSD OFF, CH1 & CH2 return to 24V, safety circuit de-energized

3. AUX Auxiliary Output Wiring (Standard PLC)

Gray AUX (NPN):

AUX emitter internally connected to 0V; collector requires external 24V pull-up to standard PLC DI

Standard DI wiring: 24V → DI terminal; Gray wire to DI common

Door closed: AUX ON → DI ON; Door open: AUX OFF → DI OFF

Usage: HMI door status display, alarm indication; must not be used for safety stop logic

4. Cascading Overview (Multiple GS-11N5 in series to Safety PLC)

Used for multiple safety doors in series detection, max. 30 units

1. OSSD1 (Black) of previous GS → Safety Input1 (Red/Black) of next GS
2. OSSD2 (White) of previous GS → Safety Input2 (Red/White) of next GS
3. Last GS-11N5: OSSD1 & OSSD2 connect to dual safety inputs of safety PLC
4. Safety Inputs of first GS shorted to 0V

Note: Total response time accumulates in cascade; safety evaluation must calculate total delay. Any door open will cut off OSSD for the whole chain.

5. Safety PLC Program Configuration Points
6. Channel Mode: Set as Dual-channel safety input, enable cross monitoring for channel discrepancy
7. Discrepancy tolerance time: 20~50ms typically, do not set excessive value
8. Fault action: Channel mismatch → safety stop, latch fault, reset signal required
9. Do not use AUX signal for safety stop logic; use only for diagnostic alarm
10. After program download, full function test: door closed allow run, door open immediate stop, single wire break triggers safety fault
11. Site Commissioning Checklist
12. Pre-power check: Red/Black & Red/White shorted to 0V (single unit), Light Blue insulated
13. LED test: Actuator near → solid green; actuator removed → solid orange; no red LED
14. PLC signal: CH1 & CH2 go low simultaneously when door closed; high when door open
15. Fault simulation: Disconnect Black or White wire individually; PLC must detect channel mismatch and trigger safety fault
16. Cable parasitic capacitance: Use shielded cable for wiring >20m, shield grounded at single end to prevent false OSSD action
17. Common Pitfalls
18. ❌ Red/Black & Red/White floating for single unit: immediate red latch-up, frequent beginner wiring mistake
19. ❌ AUX Gray wire connected to safety PLC safety channel: safety certification invalid, major hazard
20. ❌ NPN OSSD directly to sourcing safety input: reversed logic, cannot work properly
21. ❌ Safety PLC set to single channel mode: loss of cross-channel fault detection, safety rating downgraded

KEYENCE GS Series Safety Gate Switch Full Model List

GS series is divided into three categories: GS-10 Non-locking non-contact magnetic safety switch (GS-11N5 belongs to this group), GS-50 Solenoid locking (Power-to-release), GS-70 Solenoid locking (Power-to-lock)

Model coding rule:

N = NPN output; P = PNP output

5 = 5m bare cable; 10 = 10m bare cable; PC = M12 connector (0.3m short pre-cable)

11=Standard; 10=Basic; 13=High-function; 51/71=Locking standard; 53/73=Locking high-function

1. Non-contact Type (No solenoid lock, magnetic safety switch GS10 Series)

Only for door position detection, no locking function; PLe / Cat4 / SIL3, up to 30 cascaded units

2. Solenoid Lock GS-50 Series (Power-to-release: Locked when powered, unlocked on power loss)

Locking logic: Keep energized to hold lock; door releases automatically upon power failure. Suitable for safety guard doors, safety chambers.

3. Solenoid Lock GS-70 Series (Power-to-lock: Lock only when energized)

Unlocked when power off; coil must be energized to engage lock. Suitable for robot safety doors.

4. Matching Actuators (Magnetic head, mandatory for GS main unit)

5. Mounting Brackets & Accessories

GS-B01, GS-B11, GS-B21, GS-B31, GS-B41, GS-B33, GS-B43

6. Other Accessories

GS-T01: Test Tool

✅ Quick Selection Guide

1. Only door detection, no locking → GS-10 series (GS-11N5/GS-11P5)
2. Lock required, auto unlock on power loss → GS-50 series
3. Lock required, lock only when powered → GS-70 series
4. High-function models (GS-13/53/73): support EDM external diagnostic, manual reset; GS11/51/71 standard versions do not support EDM.

Remark: GS models with SO suffix (GS-10PCSO / GS-11PCSO / GS-51PCSO / GS-71PCSO) are special custom versions, rarely used in general projects.