2.5 E-Stop direct series connection
Some GS models have safety input terminals that allow the emergency stop button to be directly connected in series with the safety circuit, eliminating the need for a separate emergency stop module. For example, the emergency stop normally closed contact is connected to the Safety Input of the switch. When the emergency stop is pressed, the OSSD output of the switch is synchronously cut off.
2.6 Flexible Encoding and Anti tampering
Low encoding mode: Any GS series actuator can be triggered, suitable for quick replacement.
High encoding mode: The switch locks the unique actuator through a learning mode to prevent unauthorized keys or foreign objects from forcibly triggering on-site personnel.

Chapter 3 Selection and Accessories Guide
3.1 Model Naming Rules
The GS Series is encoded according to the following rules: GS-5x (non-contact type) or GS-7x (locked type), and further subdivided based on cable type and output logic.
Basic Model Type Output Logic Cable Form
GS-51P5 non-contact PNP 5-meter standard cable
GS-51N10 non-contact NPN 10 meter standard cable
GS-71PC Locking PNP M12 Connector (8-Pin)
GS-73PC Locking PNP M12 Connector (12 Pin)
M12 connector type requires additional ordering of cables (such as GS-P5C5, GS-P8C5, GS-P12C5), with different pin numbers corresponding to different functions: 5-pin only provides OSSD and power supply; 8 needles increase AUX and EDM; 12 pin supports complete cascading and reset functions.
3.2 Special installation bracket
To meet the on-site installation needs that are tailored to local conditions, Keyence offers a variety of brackets:
GS-B01: Universal L-shaped bracket
GS-B11: Flat bracket for sliding doors (left/right optional)
GS-B41/GS-B43: Special bracket for hinged doors, supporting outward or inward opening of the door body
GS-H01/GS-H02: Locking type dual action handle (requires pressing and sliding to unlock)
The brackets are equipped with mounting screws, made of galvanized steel or stainless steel, and can be directly welded or bolted in place.
3.3 Cable and Y-shaped splitter
For scenarios with double doors or the need to monitor two entrances simultaneously, it is recommended to use a Y-shaped connector (such as GS-Y5P). This connector divides a safety signal source into two paths, which are respectively connected to the left and right door switches, and each switch can still output an independent AUX signal, making it easy for the upper computer to identify the specific door opening position. The Y-shaped connector, when paired with standard M12 extension cables (1m, 5m, 10m, 20m), can easily build a distributed secure network.
Chapter 4: Practical Installation and Wiring
This chapter provides a detailed description of the installation steps using the most common locking type (M12 8-pin) and non-contact type (5-meter cable) as examples.
4.1 Key points of mechanical installation
Determine installation position: For the locking type, the actuator (key) must be inserted vertically into the switch slot, with an insertion depth of ≥ 15mm and an inclination angle of ≤ 5 °. The non-contact type allows for a larger tilt angle (± 15 °) while keeping the head parallel to the actuator.
Use a dedicated bracket for fixation: First, fix the bracket to the machine frame with screws, and then install the switch body. The elongated holes on the bracket can be adjusted in position to compensate for welding or assembly errors.
Door side actuator adjustment: After installing the actuator on the door, slowly close the door and check if the actuator can smoothly enter the switch head. If stuck or rubbed, perform three-axis alignment through shims or long holes.
Connecting the grounding wire: The metal casing must be connected to the system grounding through a bracket or an independent grounding wire to prevent static electricity accumulation and misoperation.
4.2 Electrical Wiring - Non Contact Type (Cable Direct Output)
Non contact type is usually equipped with 5m or 10m standard cables, containing 4 wires inside:
Brown:+24V DC
Blue: 0V
Black: OSSD output 1
White: OSSD output 2 (redundant safety output)
(Optional gray: AUX output)
Wiring steps:
Connect the brown color to the safety power supply+24V and the blue color to 0V.
Black and white are respectively connected to the two safety input channels of the safety relay (such as S11 and S21).
If using AUX output, connect the gray line to the PLC digital input module (PNP type source input, NPN type drain input).
Check that the OSSD output remains high (+24V) when the door is closed and drops to 0V when the door is open.
4.3 Electrical Wiring - Locking M12 Connector
Taking the 8-pin model (GS-71PC) as an example, using GS-P8C5 standard cable, the wire color is defined as follows (refer to Keyence definition):
Explanation of Needle Number Line Color Signal
1 brown+24V power supply positive
2 white safety inputs 1 from the previous level OSSD or reset button
3 blue 0V power supply negative
4 Black OSSD Output 1 Safe Output Channel A
5 gray OSSD outputs 2 safe output channels B
6 Pink Lock Control High Level (24V)=Lock, Low Level=Unlock
7 yellow EDM feedback input connected to contactor auxiliary contact