3TK2824-1AL20 Siemens Safety Control Relay

Product Overview

The Siemens 3TK2824-1AL20 is a robust and compact Safety Control Relay from the Sirius 3TK28 series, a flagship safety product line from Siemens. Designed for standard safety applications in machine building and process automation, this relay provides a reliable solution for monitoring safety functions like E-stops, safety gates, and two-hand controls. It is engineered to meet international safety standards, offering a cost-effective way to implement safety logic without the need for a complex safety PLC.

As part of the 3TK28 family, the 3TK2824-1AL20 features a modular design with screw-type terminals, making it easy to install and replace. It is specifically configured with 2 Normally Open (NO) safety contacts and operates on a 230V AC control voltage, making it suitable for a wide range of industrial power systems.

Key Product Highlights:

• Series: Sirius 3TK28 (Safety Relays)
• Type: Safety Control Relay
• Contact Configuration: 2 NO (Normally Open)
• Control Voltage: 230V AC
• Safety Rating: Category 3, PL c (EN ISO 13849-1), SIL 1 (IEC 61508)
• Mounting: Screw terminals (DIN rail or direct mount)

Key Features & Benefits

• High Safety Integrity:

• Dual-Channel Architecture: Utilizes a proven dual-channel design to ensure that a single fault does not lead to a loss of the safety function.
• Certified Performance: Meets the requirements for Category 3 and Performance Level c (PL c) according to EN ISO 13849-1, and SIL 1 according to IEC 61508, making it suitable for medium-risk applications.
• Forced-Guided Contacts: The internal relay contacts are mechanically linked (forced-guided), ensuring that if a contact welds, the opposing contact remains open, preventing dangerous situations.

• Flexible & User-Friendly:

• Screw Mounting: Features screw-type terminals for easy wiring and secure connections, eliminating the need for special tools. It can be mounted on a DIN rail (EN 60715) or directly to a surface.
• Compact Design: With a width of only 22.5mm, it saves valuable space in control cabinets, allowing for dense packing of control components.
• Clear Status Indication: Equipped with LED indicators for power, channel status, and output state, simplifying troubleshooting and commissioning.

• Robust Construction:

• Industrial Grade: Designed to withstand harsh industrial environments with a wide operating temperature range (-20°C to 60°C).
• Conformal Coating: Internal circuitry is often coated to protect against moisture, dust, and corrosive gases, enhancing reliability in demanding conditions.
• High Contact Capacity: The 2 NO contacts are rated for 6A at 230V AC/DC, capable of handling significant loads or driving intermediate contactors.

Technical Specifications

Typical Applications

The 3TK2824-1AL20 is widely used in various industrial applications where functional safety is critical:

• Emergency Stop Circuits: Monitoring E-stop buttons and initiating a safe shutdown of machinery.
• Safety Interlocks: Controlling access to hazardous areas via safety gates, doors, and light curtains.
• Two-Hand Control: Ensuring an operator's hands are safely positioned before a machine cycle can start (e.g., press brakes, stamping machines).
• Safety Gate Monitoring: Detecting if a guard is closed and locked before allowing the machine to operate.
• Overspeed Monitoring: Working with sensors to stop a motor if it exceeds a safe speed.
• Process Safety: Monitoring critical process variables (pressure, temperature) and initiating a safe shutdown if limits are exceeded.

Related Products & Series

The 3TK2824-1AL20 is part of the extensive Sirius 3TK28 safety relay family. Related products include:

• Same Series (3TK2824):

• 3TK2824-1AJ20: 2 NO contacts, 115V AC control voltage.
• 3TK2824-1BB40: 2 NO contacts, 24V AC/DC control voltage.
• 3TK2824-2AL20: 2 NO + 2 NC contacts, 230V AC control voltage.
• 3TK2824-2CB30: 2 NO contacts, 24V AC/DC control voltage, spring terminals.

• Other 3TK28 Series:

• 3TK2820: Safety relays with 3 NO + 1 NC contacts.
• 3TK2822: Basic safety relays with 2 NO contacts.
• 3TK2823: E-stop safety relays.
• 3TK2830: Safety relays with semi-conductor outputs (solid-state).

• Accessories:

• 3TX7002-1AB00: Auxiliary contact block for side mounting.
• 3TX7001: Test adapter for easy verification of the safety function.

• Newer Generation: For more complex applications, the 3SK11 series offers configurable safety relays with advanced diagnostics.