In high-risk automated equipment such as robot workcells and CNC machining centres, conventional mechanical safety switches can only monitor door status without locking guard barriers. If operators forcibly open safety doors while machinery is running, severe safety accidents may occur. Schmersal AZM series electromagnetic safety interlock locks from Germany integrate door status detection and electromagnetic locking in one unit, classified as locking interlocking devices conforming to EN ISO 14119. While equipment operates, the electromagnetic lock remains engaged to prevent unauthorised door access. The lock can only be released after the control system issues a safe stop command to open the guard door. This mechanism effectively stops unauthorised entry into hazardous zones during operation and serves as a critical safety component for advanced automated production lines.
Schmersal’s electromagnetic safety interlock locks are dominated by the AZM product family, including compact variants, RFID-coded intelligent models and heavy-duty high-holding force versions. Below are 20 widely used standard models:
AZM161SK-12/12RKA-024
AZM161SK-12/12RK-M16-24V
AZM170-02ZRK-24VAC/DC
AZM170SK-02/10ZRK-2197
AZM190-02/01RKA-24VDC
AZM190-B3/1X7,5
AZM201Z-SK-T-1P2PW-A
AZM201B-ST2-T-1P2PW
AZM300B-I2-ST-1P2P
AZM300B-I2-ST-1P2P-A
AZM300Z-ST-1P2P
AZM300Z-I2-ST-AS
AZM400-11ZK
AZM40-B1
AZM150-02ZK
AZM150I-11ZK
AZM161I-02/12RKA
AZM201D-ST-1P2P
AZM415-22ZPK
AZM300Z-I2-ST-AS-P
Designed for hinged doors, sliding gates and large perimeter guard fences, these products are deployed across a broad spectrum of high-end industrial sectors: automotive welding production lines, robot workcells, lithium battery manufacturing equipment, CNC machining centres, injection moulding and rubber & plastics machinery, packaging equipment, food & beverage processing lines, automated logistics sorting systems, printing machinery, wind turbine compartment monitoring, rail transit inspection equipment, pharmaceutical automated production lines, woodworking machinery and hydraulic stamping equipment. They are ideal for applications with crushing, cutting and collision hazards, especially when inertial coast-down occurs after machine shutdown and access during operation must be strictly prohibited.
Compared with ordinary electromagnetic door locks, Schmersal AZM electromagnetic safety interlock locks deliver five core advantages:
First, superior safety performance complying with global standards. Equipped with positive-opening contact mechanisms, the locks achieve PLd/PLe and SIL2/SIL3 safety levels when paired with safety relays. Optional RFID-coded actuators prevent safety circuit bypassing by foreign objects and offer tamper protection to eliminate risks of intentional short-circuiting on site.
Second, flexible locking logic for diverse process requirements. Both power-to-lock and power-to-unlock modes are available to suit inertial stop machinery and robot safety fencing. Many models feature generous mounting tolerances to accommodate minor guard door deformation over long-term operation and reduce jamming failures.
Third, outstanding environmental adaptability. Main variants reach IP67 protection class; hygienic versions support IP69K high-pressure washdown. A wide operating temperature range enables stable performance amid dust, coolant splashes, oil and moisture, making them suitable for cleanrooms in food and pharmaceutical industries. Metal housing options provide enhanced impact and vibration resistance for demanding heavy-industry environments.
Fourth, strong intelligence and system integration. Premium AZM201 and AZM300 series feature LED status indicators to visualise locking, unlocking and fault signals. Safety series wiring supports multi-door networking and compatibility with safety PLCs and AS-i Safety at Work bus systems to simplify cabinet wiring. Accessories for emergency escape release and external manual unlock guarantee safe personnel evacuation in emergencies.
Fifth, comprehensive accessory portfolio and extended service life. A complete range of actuators, mounting brackets and handle assemblies fits 40 mm aluminium profiles and standard safety fences. The switches support screw terminals, spring-cage terminals and M12/M23 quick connectors. Full-range CE certifications facilitate global machinery export.
As industrial safety regulations become increasingly stringent, advanced automated equipment faces higher safety protection requirements. Unlike mechanical safety switches without locking capability, Schmersal AZM electromagnetic safety interlock locks provide active locking functions to eliminate risks caused by misoperation. Backed by proven technology, extensive model selection and reliable industrial performance, the AZM series is the preferred safety solution for machinery manufacturers building compliant safety systems, continuously delivering human-machine safety protection for global smart manufacturing.
Related Solenoid Safety Locks
Browse the complete Schmersal Solenoid Safety Locks range. Representative models available through Glorient:
Solenoid interlocks deliver PL d / PL e guarding. For how to determine your required level, see SIL vs PL Explained: Performance Levels, Safety Categories and Component Selection.
Frequently Asked Questions
What is the difference between a safety door switch and a solenoid interlock?
A door switch only monitors the guard position. A solenoid interlock, such as the AZM series, also locks the guard door with a holding force so it cannot be opened until the machine reaches a safe state, protecting against dangerous overrun.
What locking force do I need?
The required locking force depends on the application risk. Standard AZM interlocks provide roughly 1000 to 2000 N of holding force. Choose a higher force for heavier doors or applications where significant forces could act on the guard.
What is the difference between power-to-lock and power-to-unlock?
Power-to-lock means the door is locked while energized and unlocks on power loss (fails open). Power-to-unlock means the door is locked when de-energized and requires power to unlock (fails locked). Choose based on whether process safety or personnel safety takes priority.