Siemens 3TK2825-1AL20 SIRIUS Safety Relay
Warranty: 1 year
Condition : brand new in factory sealed box
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Detail
- Product NameSiemens 3TK2825-1AL20 SIRIUS Safety Relay
- Item NO.3741810
- Weight0.5000 kg = 1.1023 lb = 17.6370 oz
- CategoryPLC
- BrandSiemens
- Creation Time2026-08-20
3TK2825-1AL20
Overview
3TK2825-1AL20 is a safety relay from Siemens' SIRIUS 3TK28 series, designed for monitoring emergency-stop circuits and safety-related applications in industrial environments. It provides reliable safety function with positively-driven relay enabling circuits.
The device features 3 NO (normally open) enabling contacts and 2 NC (normally closed) signaling contacts, supporting both single-channel and two-channel control configurations. It is designed for 230 V AC control supply voltage and uses screw-type terminals for secure electrical connections.
The 3TK2825-1AL20 achieves Safety Category 4 (EN 954-1), Performance Level e (PL e) (ISO 13849-1), and SIL 3 (IEC 61508/EN 62061), making it suitable for high-demand safety applications. Its positively-driven contacts ensure that if one contact welds, the other contact is used to shut down the circuit safely.
- Siemens SIRIUS 3TK28 Series
- 3 NO enabling contacts
- 2 NC signaling contacts
- 230 V AC control supply
- Screw terminals
Specifications
Electrical & performance
| Manufacturer | Siemens |
| Model | 3TK2825-1AL20 |
| Series | SIRIUS 3TK28 |
| Product type | Safety Relay (Basic Unit) |
| Control supply voltage | 230 V AC (50/60 Hz) |
| Enabling contacts (NO) | 3 (positively-driven) |
| Signaling contacts (NC) | 2 |
| Rated insulation voltage | 300 V |
| Surge voltage resistance | 4,000 V |
| Power loss (max) | 2.5 W |
| Max switching frequency | 1,000 operations/hour |
| Electrical endurance (typical) | 100,000 operating cycles |
Physical & environmental
| Mounting | Screw and snap-on mounting (35mm DIN rail) |
| Protection class (enclosure/terminals) | IP20 / IP20 |
| Degree of pollution | 3 |
| Operating temperature | -25°C to +60°C |
| Storage temperature | -40°C to +80°C |
| Terminals | Screw-type |
Features
Safety & monitoring functions
- Emergency-stop monitoring — Designed specifically for EMERGENCY-STOP circuit monitoring, ensuring safe shutdown of machinery in critical situations.
- Multi-sensor compatibility — Supports monitoring of position switches, safety switches, magnetic switches, floating sensors, and safety-related circuits.
- Dual-channel control — Supports both single-channel and two-channel operation, with cross-circuit detection (minimum fault current k_min = 0.5 A).
Diagnostics & configuration
- Positively-driven contacts — If one contact welds, the other contact is used to shut down the circuit safely, ensuring fail-safe operation.
- LED status indication — Three LEDs (POWER, CHANNEL 1, CHANNEL 2) provide visual indication of operating state and fault conditions.
- Cross-circuit proof design — Detects cross-circuits in the EMERGENCY STOP circuit, improving system safety and reliability.
Applications
The 3TK2825-1AL20 is widely deployed in safety-critical industrial applications requiring reliable emergency-stop and protection functions.
Lifecycle
Active currently in production — fully supported
Product status: The 3TK2825-1AL20 remains an active, supported product in Siemens' SIRIUS 3TK28 safety relay portfolio. It continues to be a reliable solution for safety applications up to PL e / SIL 3.
Spare parts & support: Replacement units and accessories are available through Siemens' standard support channels and authorized distributors. The SIRIUS safety relay family is designed for long‑term availability.
Cable length guidelines:
- Single-channel control (2-core cable): Max 1000 m with 1.5 mm² copper wire cross-section; 1666 m with 2.5 mm².
- Two-channel control (for Categories 3 & 4): Max 500 m with 1.5 mm² cross-section; 833 m with 2.5 mm².
Recommendation: For new installations requiring emergency-stop monitoring up to PL e / SIL 3, the 3TK2825-1AL20 remains a reliable and cost-effective solution. For applications requiring longer cable lengths (>1000 m), consider the 3TK2826 series.
FAQ – Frequently Asked Questions
It achieves Safety Category 4 (EN 954-1), Performance Level e (PL e) (ISO 13849-1), and SIL 3 (IEC 61508 / EN 62061).
It operates on 230 V AC (50/60 Hz) control supply voltage.
It features 3 NO (normally open) enabling contacts and 2 NC (normally closed) signaling contacts, all positively-driven.
For single-channel control: up to 1000 m with 1.5 mm² cable. For two-channel control: up to 500 m with 1.5 mm² cable.
Yes, it remains an active, supported product in Siemens' SIRIUS 3TK28 portfolio.
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